Event Budget Planner

An event budget is not a shopping list. It is a moving picture of three different numbers per supplier, a guest count that changes everything when it shifts, and a run of payments that all want clearing before the same weekend. This article explains what each control on the page does, why the tool keeps your guess, the supplier's quote and the final bill in three separate columns instead of one, and how to read the payment schedule it builds from the balances you still owe.

Whole pennies: how a typed price becomes a line total

No amount in this tool is ever held as a decimal number. A price becomes a whole number of pennies the moment it is read, and it turns back into pounds and pence only when it is printed. The reason is the per-head lines. A rate of 52.50 multiplied by 137 covers is exactly the kind of sum that drifts by a penny in ordinary decimal arithmetic, and then disagrees with the caterer for no visible reason.

Before a price becomes pennies, the text is cleaned. Everything that is not a digit, a dot or a minus sign is dropped. So a cell holding £1,250.50 arrives as 125050 pennies, and so does a cell holding 1,250.50. That cleaning matters most for imported files. On the page itself the amount boxes are number fields, so your browser has usually turned away odd text before the tool ever sees it.

Three inputs read as nothing rather than as a mistake: an empty box, a box holding only a dot, and a box holding only a minus sign. A figure the browser cannot make sense of, such as one typed with two dots in it, also reads as nothing. Nothing here means zero pennies, and it happens quietly. If a line ever totals less than you expect, that is the first thing to look at.

Two of the counts are cut down to whole units before anything else. Qty is one, and the guest count is the other, so 80.7 guests is read as 80. A guest count of zero or less is read as no guests at all, which is why per-head lines can suddenly come to nothing, and why the warnings panel says so. The contingency percentage is held between 0 and 100, so a stray 150 is treated as 100.

A line only joins the sums when it has a description, or a figure above zero in Estimate, Quote, Actual or Deposit. A supplier name and a due date on their own are not enough. That is what stops the spare empty row at the foot of the list from doing any harm.

Because a rate is settled to whole pennies before it is multiplied, a rate given in fractions of a penny will move. Take a per-head rate typed as 12.345, with 80 guests. The rate becomes 12.35, so the line reads 988.00. Multiplying first and rounding afterwards would have given 987.60. Exact half-penny cases depend on the value your browser stores for that decimal, so it is not worth leaning on them. Type the rate you are actually being charged and the question goes away.

Cost per head is rounded the same way, and you can watch that rounding in the example the page opens with. The projected total there is 14,884.10 for 80 guests, and the cost per head is shown as 186.05. Multiply 186.05 back by 80 and you get 14,884.00. The missing 10 pence is the rounding. If you are collecting a contribution per person, round your asking figure up, or somebody has to cover the gap.

One limit is worth naming. The sums always run in hundredths, whatever currency you choose. For a currency with no small unit, such as the yen or the won, figures are rounded to whole units for display only. A column of printed lines may then fail to add up to the printed total. The stored figures are still right; it is the display that has dropped the fraction.

That is the whole chain, and it is worked out again on every keystroke:

• Rate: the price you typed, rounded to the nearest penny.
• Units: the Qty box when it holds 1 or more. When Qty is empty or zero, a fixed line counts as 1 unit and a per-head line takes the guest count.
• Line total: rate multiplied by units.
• Balance: the line total minus the deposit. The deposit is never multiplied by anything.
• Subtotal: every line total added together.
• Contingency: the base multiplied by the percentage, divided by 100, rounded to the nearest penny once, at the end.
• Projected total: subtotal plus contingency.
• Cost per head: the projected total divided by the guest count, rounded to the nearest penny.

The four Working figure rules, and what Actuals only really shows

The Working figure dropdown does not pick a column for the whole budget. It picks a rule, and that rule is then applied to each line on its own. Two of the four have a fallback and two do not.

The ones with no fallback are the sharp instruments. Under Estimates only, a line you never estimated counts as nothing, even if you are holding an invoice for it. Under Actuals only, every line you have not yet been billed for counts as nothing.

In the example the page opens with, Best known and Quotes where given give the same subtotal of 13,531, in whichever currency you have chosen. Only one line carries an actual figure, the flowers, and the florist billed exactly the 780 that was quoted. So both rules land on the same rate for every row. Switch to Estimates only and the subtotal falls to 12,966. Contingency at 10 per cent becomes 1,296.60, the projected total is 14,262.60, and the panel reports 262.60 over the 14,000 target.

Actuals only shows what the rule is really doing. Nothing but the flowers has been billed, so the subtotal is 780. Ten per cent of that is 78, the projected total is 858, and the cost per head is 10.73. Against the 14,000 target the panel now says 13,142.00 under. That is not a budget. It is a record of what has genuinely been invoiced so far, which is useful to look at and dangerous to plan from.

Two panels then do something that catches people out. Deposits are no part of the working figure. They are money that has already gone out, so they stay at 2,930 whichever rule you pick. Still to pay is the projected total minus deposits, so it goes negative and shows minus 2,072.00. At the same time Balances outstanding reads zero and the payment schedule empties. A balance is a line total minus that line's own deposit, and only balances above zero are ever scheduled, so eight lines drop straight out. The warnings panel puts it plainly: eight lines have no price under the working figure you have chosen.

Those two figures never cancel each other out, and it helps to know why. Balances outstanding adds up positive balances only, so an overpaid line adds nothing to it. Still to pay takes off every penny of deposit, overpayment included. When a deposit is larger than the line it sits on, the two numbers drift apart, and the warning about a deposit bigger than its own line is the clue that it has happened.

Two more things hold still while the dropdown moves. The Estimate, Quote and Actual totals on the printed sheet are always the totals of those three columns; only the Budget column follows the rule you picked. And the contingency setting for lines with no firm quote looks at what you typed, not at the rule. It asks whether the Quote box or the Actual box holds a figure. So with Actuals only and that setting together, contingency comes out at nothing at all. The only two lines with no quote are stationery and gifts, and neither has an actual figure either, so there is no base left to take a percentage of.

There is one practical consequence for files you send on. In the downloaded CSV, the Budget column and the projected total and contingency in the summary rows are all written using whichever rule was showing when you pressed the button. The three rate columns and the three column totals are not affected by it. If the file is going to somebody else, tell them which setting it came from.

The four rules in full, each one applied line by line:

• Best known: the Actual rate; if that is empty, the Quote; if that is empty, the Estimate.
• Quotes where given: the Quote; if that is empty, the Estimate.
• Estimates only: the Estimate, with nothing to fall back on.
• Actuals only: the Actual rate, with nothing to fall back on.

The four questions an event budget has to answer

Whether you are planning a wedding for eighty, a school leavers' ball for three hundred or a company away day for twelve, the same four questions come up. What will the whole thing cost? Is that more or less than we said we would spend? What is each person costing us? And what has to be paid, to whom, by when?

Most people try to answer all four in a single spreadsheet column of prices. It works for about a fortnight. Then the caterer sends a quote that is higher than your guess, the florist invoices something different again, and the venue asks for a deposit that is not the whole fee. The single column cannot hold any of that, so it gets overwritten, and the record of what you originally thought disappears.

This tool keeps the four questions apart on purpose. Each budget line carries its own estimate, quote and actual figure. Each line can be priced per head or as a flat fee. Each one records what you have already handed over as a deposit and when the rest falls due. The totals, the variance and the schedule all fall out of those facts rather than being typed in separately.

Guest count is the number that moves everything

The box marked Guests sits near the top of the page for a reason. In almost every event budget, more than half the money is a per-head figure in disguise. Food, drink, favours, place cards, table settings, sometimes even the venue's minimum spend all scale with the number of people who walk through the door.

That makes the guest count the single riskiest number on the page. A caterer at fifty pounds a head does not care whether you invited eighty or ninety, but the difference between those two invitations is five hundred pounds. Nobody plans for that. They plan for the caterer putting the price up, which almost never happens once a quote is signed.

So try it. Put the guest count ten higher and watch the projected total move. If the answer frightens you, the honest response is to book fewer things, not to hope fewer people accept. Put the number back afterwards; nothing is lost, because everything on the page recalculates the moment you change it.

There is one wrinkle worth knowing. A per-head line follows the guest count only when its Qty box is empty. If a line genuinely covers a different number of people, put that number in Qty and it overrides the guest count for that row alone. Twelve children's meals at a lower rate, forty people staying for the evening buffet, sixty needing a coach seat: each of those is its own line with its own Qty.

Three money columns, and why one is never enough

Every line has three price boxes side by side: Estimate, Quote and Actual. They are filled in at different times and none of them ever replaces another.

Estimate is what you put down before you have spoken to anybody. It might come from a friend who did the same thing last year, from a supplier's website, or from a straight guess. It is the number that makes the first version of the budget possible at all.

Quote is what a supplier has told you in writing. It is the first number you can plan around, though it is still not money that has moved.

Actual is what you were finally billed. Sometimes it matches the quote exactly. Often it does not, because a supplier added a delivery charge, or the final numbers came in lower, or something was added on the day.

Keeping all three means you can answer questions after the event that nobody can normally answer. Did the caterer come in over? Was our original guess for flowers wildly optimistic? Which supplier's quote was worth trusting? That is the information that makes the next event's budget realistic instead of hopeful, and it is exactly what gets destroyed when people overwrite one cell with a newer figure.

The Working figure dropdown decides which of the three the totals actually use. Best known walks down from Actual to Quote to Estimate for each line separately, so the total is always built from the most solid information you happen to have. Estimates only shows the budget you set out with. Actuals only shows what has genuinely left your account so far, which is a useful sanity check and usually a much smaller number than people expect.

Per head, fixed, and what Qty really means

Each line has a Pricing dropdown with two settings. Per head means the price you typed is the price for one guest. Fixed means the price is for the whole job.

The distinction matters more than it looks. A band charges one fee whether forty people dance or a hundred and forty. A caterer charges by the cover. If you mark the band per head by accident, the budget swells by thousands and you will spend an afternoon hunting for the cause.

Qty handles the cases that fit neither pattern cleanly. On a fixed line it means how many of the thing you are buying: two coaches at a hundred and ninety-seven pounds fifty each, three hours of overtime, four trestle tables. On a per-head line it means how many people this particular line covers, overriding the guest count.

Leave Qty empty for the ordinary case. Empty means one on a fixed line and the guest count on a per-head line, which is what you want almost every time.

Deposits and balances: what has actually gone out

The second row of every line holds three more things: the supplier's name, the deposit you have already paid, and the date the balance falls due.

The deposit box is the one place on a budget line where you type a real sum of money rather than a rate. It is never multiplied by the guest count, never multiplied by Qty. If you paid the venue a thousand pounds to hold the date, you type a thousand, regardless of how many people are coming.

This trips people up often enough that the tool watches for it. If a deposit ends up bigger than the line it sits on, you get a warning, because the overwhelming likely cause is a per-head rate typed into the deposit box.

The balance for a line is simply the working figure minus the deposit. Add up every positive balance and you have the amount still to find. Note that deposits reduce what you owe but never reduce what the event costs. A venue at three thousand four hundred and fifty is a venue at three thousand four hundred and fifty whether you have paid a deposit or not.

The payment schedule, and why it beats the total

The panel headed What is due when takes every outstanding balance, groups it by its due date and puts the dates in order. Balances with no date sit at the end. Each row also shows a running cumulative figure.

This is the view that actually stops people getting into trouble. Knowing an event will cost fifteen thousand is not the problem. The problem is discovering in the same week that the caterer wants five thousand two hundred and the band wants eight hundred and fifty and the coach company wants paying on the Friday. A total cannot show you that. A schedule can.

Rows are marked when a date has already passed, and marked again when a balance falls due after the event itself. The second one is usually a typing slip in the month or the year, though it is occasionally genuine, for a photographer's album or a returnable damage deposit.

The contingency figure is deliberately not scheduled against anyone. It is money you are holding back, not money anybody has asked for, and putting it in the schedule would give it a false air of certainty.

Contingency: how much, and against what

The contingency box takes a percentage. Ten is the usual starting point for an event with a lot still unbooked, and five is reasonable once nearly everything is signed. The tool works out the cash figure and adds it as its own line in the totals.

The dropdown beside it decides what the percentage is applied to. Every line means what it says: a straight percentage of the whole working subtotal. Only lines with no firm quote applies it just to the rows where neither the Quote nor the Actual column has anything in it.

Both settings are defensible, and they are defensible at different moments. Early on, when most of the budget is guesswork, hold contingency against everything. Later, when eight of your ten suppliers have given you prices in writing, keep it only against the two that have not. Carrying ten per cent against a price that cannot move any more just inflates the figure you report to whoever is paying, and inflated figures get argued with.

In the worked example below, the difference is stark. Ten per cent of everything is one thousand three hundred and fifty-three pounds and ten pence. Ten per cent of the two unquoted lines is sixty-one pounds and sixty pence. Same budget, same day, very different headline.

A worked example: eighty guests, target fourteen thousand

The page opens with a reception for eighty people and a target of fourteen thousand. It is worth walking through, because it exercises every part of the tool.

The venue is a fixed three thousand four hundred and fifty, quoted, against an original estimate of three thousand two hundred. Catering is a per-head line: fifty-two pounds fifty quoted against forty-eight estimated, which at eighty covers comes to four thousand two hundred rather than the three thousand eight hundred and forty first pencilled in. Drinks are nineteen pounds twenty-five a head, so one thousand five hundred and forty. Flowers came in under estimate at seven hundred and eighty and have been paid in full, so that line shows an actual figure and no balance. The band is one thousand one hundred and fifty, the photographer one thousand four hundred, stationery three pounds twenty a head, gifts four pounds fifty a head, and transport is two coaches at one hundred and ninety-seven pounds fifty.

That comes to thirteen thousand five hundred and thirty-one on best known figures. The original estimates would have made it twelve thousand nine hundred and sixty-six, so the budget has already drifted upward by five hundred and sixty-five before anything unexpected has happened at all. This is normal, and it is the reason contingency exists.

Add ten per cent and the projected total is fourteen thousand eight hundred and eighty-four pounds and ten pence, against a target of fourteen thousand. The panel reports the overspend as eight hundred and eighty-four pounds and ten pence, and puts the cost per head at one hundred and eighty-six pounds and five pence.

Deposits of two thousand nine hundred and thirty have already gone out. Ten thousand six hundred and one of line balances remains, and the schedule shows the first two thousand four hundred and fifty landing thirty days before the day itself.

Now change the guest count to a hundred. The projected total jumps to sixteen thousand six hundred and thirty-two. Twenty extra people have added one thousand seven hundred and forty-seven pounds and ninety pence to the projected total, and not one supplier has changed a price.

Reading the variance and the cost per head

The target budget field is optional. Fill it in and the panel tells you how far under or over you are, updating with every keystroke. Leave it blank and everything still totals; only the comparison goes away.

Cost per head is the projected total, contingency included, divided by the guest count. It is the number to look at if you are selling tickets, charging a per-person contribution or splitting the cost between families, because your contingency has to be covered by revenue like every other pound.

Do treat cost per head carefully as a planning tool. It does not fall in proportion when you invite more people, because the fixed lines stay fixed. Going from eighty guests to a hundred in the example lowers the cost per head from about a hundred and eighty-six to about a hundred and sixty-six, while raising the total bill by about one thousand seven hundred and fifty. Cheaper per person is not the same as cheaper.

Getting a budget in and out

Download CSV writes one row per budget line with everything computed: the per-unit rates, the line totals for all three columns, the working figure, the deposit, the balance and the due date. Two summary rows go at the bottom, one for contingency and one for the projected total. Dates are always written year first in the file, whatever format the screen is set to, because a spreadsheet that has to guess whether 04/08 means April or August is how a payment gets missed.

Import works the other way and is deliberately forgiving. Drop a CSV on the box near the bottom of the page and the column names are matched loosely, in any order. Headings such as Category, Detail, Description, Estimate, Quote, Actual, Deposit, Due date, Supplier, Pricing and Qty are all recognised. Currency symbols and thousands separators in the numbers are stripped rather than rejected. The summary rows the tool writes at the bottom of its own export are spotted and ignored, so a file exported from here reimports without doubling anything.

Import replaces the lines you currently have, so export first if there is anything you want to keep. A date written with slashes is read using whichever order your Date format setting says, since there is no way to tell 04/08 from 08/04 without being told.

Print gives a one-page summary: the lines grouped under their categories with all three price columns, the totals block, the variance against target, the cost per head and the full payment schedule. It is the version to hand to whoever is paying, or to bring to a meeting where somebody will ask why the flowers cost what they cost.

Mistakes that quietly wreck an event budget

The most common is the deposit typed as a per-head rate. It makes a line look mostly paid when almost nothing has been paid, and the schedule then understates what you owe by thousands. The warning panel catches the obvious cases, but a deposit that is merely wrong rather than impossible will pass unnoticed.

Second is a fixed cost marked per head. Watch out for anything a supplier calls a day rate, a call-out fee or a minimum charge. Those are fixed, however the conversation was phrased.

Third is forgetting whole categories. Nobody forgets the venue or the caterer. People routinely forget transport, stationery, gifts, and the small run of costs on the day itself that nobody invoices in advance. The button marked Add the categories I have not used puts an empty line in for each missing one, which is a gentler prompt than a warning nobody reads.

Fourth is treating an estimate as settled. A line still sitting on an estimate months later usually means nobody has actually asked the supplier. The working figure will be built on that estimate, and it will move when the real price arrives.

Fifth is running with no contingency at all. Events overspend far more often than they underspend, and the overspend is rarely one large thing. It is forty pounds here and a hundred and twenty there, none of which felt like a decision at the time.

What this tool does not try to do

It is a budget, not an accounting system. It does not handle VAT or sales tax as a separate calculation, so enter prices on whichever basis you are actually being billed and stay consistent across the lines. It does not track deposits that are refundable separately from ones that are not. It does not do currency conversion: the currency dropdown chooses how amounts are formatted and labelled, not what they are worth.

It also does not track income. Ticket sales, contributions from family, sponsorship and bar takings all sit outside it. If your event has revenue as well as costs, the cost per head figure is the number to work with, since that is the one you have to cover.

For a multi-day event with separate budgets per day, run each one as its own budget and export both, rather than trying to squeeze them into one list of lines. The category totals only mean something when they cover one event.

Where the numbers live

Everything is worked out in your browser. Supplier names, quoted prices, what you paid and what you still owe never leave the machine you are sitting at. There is no account and no upload.

The working copy is saved locally so that closing the tab or reloading the page does not lose an afternoon's typing. That copy belongs to this browser on this device only. It is not synchronised anywhere, and it will disappear if you clear your browsing data, so download the CSV once you have something you would be upset to lose.

Start again deletes the saved copy and brings the worked example back, which is the quickest way to begin a real budget from a blank sheet once you have finished exploring.