Why proportional beats per-head once the orders differ
Dividing by head is fine when everyone ordered roughly the same thing. Once they have not, the per-head split moves money from the person who ordered lightly to the person who ordered well, and it does it twice: once on the food, and again on the tip and tax, which are percentages of a subtotal the big order created.
The approach here is to charge each person for their own items, split only what was actually shared, and then allocate tax and tip in proportion to what each person's order came to. The person who ordered a $42 steak covers more of the tip than the person who ordered a $14 salad, in the same ratio their food was in — which is what a percentage tip means in the first place.
Marking things as shared
Any line whose name is Shared — or Table, Everyone, All, Group — is divided evenly among the people who appear by name. Bread, a couple of bottles for the table, the appetizers that circulated: things where nobody can say who had how much.
Two cases need attention. If some people did not drink, do not put the wine under Shared; write it out against the names of the people who did, splitting it between them. And if someone was at the table but ordered nothing while still sharing the bread, they will not be counted unless they appear by name — give them a zero line such as Sam: nothing 0 and they join the shared split without owing anything for their own items.
The order the money is applied in
Subtotal first, then any discount comes off, then sales tax is charged on what remains, then the tip. That is the normal sequence on a US check: tax is charged on the amount you actually pay for the goods, so a coupon reduces the tax as well.
| Step | Applied to |
|---|---|
| Discount | The subtotal, spread across people in proportion to what they ordered |
| Sales tax | The subtotal after the discount |
| Tip | Either the pre-tax subtotal or the taxed total, your choice |
Tipping on the pre-tax subtotal is the default because it is the customary base and it is what most people mean by "twenty percent". Tipping on the total after tax is also common and simply costs a little more; on a $100 check at 8.875% tax the difference between the two is about $1.78 at 20%. Neither is wrong. What matters is that the table agrees which one is being used before the arithmetic starts. Note also that in most states sales tax does not apply to the tip itself, and a mandatory service charge for a large party is not a tip — if your receipt has one, enter it as a shared item rather than as a tip percentage.
Cents, and where the leftover ones go
Every figure is held in whole cents from the moment the line is read, so nothing accumulates a rounding error along the way. Three people splitting a $10.00 bread basket cannot each pay an equal amount — $3.33 three times is $9.99 — so somebody has to take the extra penny.
The allocation gives each person the whole-cent part of their exact share, then hands the leftover cents out one at a time to whoever has the largest fractional remainder. At most one person pays a penny more than their exact share, no cent is invented and none disappears, and the sum of the column always equals the bill. The check figures printed under the table let you verify that against the receipt in front of you. If you would rather collect round dollars, the rounding option does that instead, and reports the surplus explicitly rather than quietly absorbing it — that money is real and belongs to whoever paid the card.
Questions people ask
Two of us split one dish. How do I enter it?
Write it twice at half the price, once under each name: "Ana: pasta 11.00" and "Dev: pasta 11.00" for a $22 plate. That keeps each person's subtotal right, which in turn keeps their tax and tip share right. Only use the Shared label when the split is genuinely across the whole table, since that is what it divides by.
Should the tip go on the pre-tax or post-tax amount?
Pre-tax is the customary base and is the default here. Post-tax is common enough that nobody will think it odd, and it costs about a dollar and a half more per hundred at typical rates. The one thing worth avoiding is having different people at the table assuming different bases, because then the collected total does not match the check and somebody covers the gap without noticing.
The coupon only applied to one dish, not the whole check.
Then do not use the discount field, which spreads a credit across everyone in proportion. Instead, write that dish in at its already-discounted price on the line of the person who ordered it. The discount field is for something taken off the bill as a whole, such as a gift card or a percentage off the check.
Why does one person pay a penny more than the others on an even split?
Because an even split of an odd amount does not exist in cents. Ten dollars across three people is $3.33 each with a penny left over, and that penny has to sit somewhere. It goes to whoever has the largest fractional remainder, so the total is exact rather than a cent short. Over a few dinners it evens out, and if it bothers anyone the honest answer is that the alternative is a bill that does not add up.