Bill split calculator

Methodology

This tool runs the Kindhow Scale, version 1.0, and it is the first one here that splits into two answers with different provenance. The tip is a published figure applied a published way. The split is ours from top to bottom, because nobody publishes one. Those are separate surfaces on the page for exactly that reason.

The formula

the tip, once, for the table:

  sit-down     15% of the bill BEFORE TAX      sourced (Emily Post)
  bar tab      the larger of 15% or $1/drink   sourced (Emily Post)
  buffet       10% before tax, no band         sourced (Emily Post)
  counter      nothing; 10% if curbside or
               large and complicated           sourced (Emily Post)

  + where in the band the service puts you     judgment — and it retags
                                               itself if it leaves the band

  sales tax                              $0    sourced — "pre-tax" is
                                               the guide's own word
  a service charge already on the check   −$    sourced — the IRS says a
                                               payment is a tip only if you
                                               chose it and set it

  ─────────────
  = whole dollars

then the split, which is entirely ours:

  each pays their own / everyone even / food even and drinks their own
  tax and tip apportioned in the same proportion
  whole cents, largest remainder — the shares add to the check exactly

Two words nobody quotes — sourced

The Emily Post Institute’s General Tipping Guide does not say 15–20%. Its Wait Service (Sit Down) row says “15-20%, pre-tax”, and its buffet row says “10%, pre-tax”. Those last two words are the whole difference between this tool and the hundred bill splitters that already exist, and they are dropped so consistently that most people have never seen them.

It matters because sales tax is not service. Nobody at the restaurant cooked it, carried it or cleared it — the state collected it, and a percentage tipped on top of it is a tip on a tax. On the worked example above that is $9.60 of tax on a $136.00 dinner: tipping 17.5% on the after-tax total adds $1.68 to the tip and none of it reaches anybody differently. Type your tax into the box and the ledger prints that number on a line at $0, which is the only place on the internet you are likely to see it.

One consequence worth naming: this tool will usually give you a smaller number than the tablet at the counter or the suggested-tip row on your receipt. That is not us being stingy, and it is not a judgment call. It is the published figure applied to the base the publication named.

The service you had picks the rule, not the percentage

The same guide prices four different situations four different ways, and the differences are structural rather than numeric. A band has room to move inside it; a single figure does not. A row that opens with “no obligation” is not a smaller version of one that does not.

We start at the floor of a band rather than in the middle, which is the same decision the delivery tip calculator makes and for the same reason: everything above the floor is ours, and starting low is what keeps each of those additions visible as its own line instead of hidden inside a number that was already generous before you told it anything.

The bar row is the one that prices the same tab twice — “$1-2 per drink or 15-20% of the tab” — so on a short round of cheap drinks the per-drink figure comes out larger than the percentage. The tool computes both, takes the larger, and says on the ledger which of the two rules won. Both figures are Emily Post’s; taking the larger is the only part of it that is ours.

Where in the band — and where the band ends

The service control moves you between the floor and the ceiling of whatever band applies. The band is published; the position inside it is not, so that line reads sourced while the resulting percentage is still inside the published range, and retags itself house judgment the moment it is not. There is exactly one setting that leaves the band — “it was genuinely bad”, which drops five points under Emily Post’s floor — and it is the only setting on this tool whose tag is computed rather than declared. The same discipline runs the teacher gift calculator.

A service charge is not a tip — and it never was

The automatic 18% on a party of six is the single most common reason somebody tips twice. It is not a tip, and two federal authorities say so in almost the same words. The IRS puts the test plainly: “A payment is a tip only if the customer voluntarily decides to pay it and determines the amount.” A charge the restaurant added, at a percentage the restaurant set, is neither — so it is a service charge, and service charges “when distributed to an employee, are generally treated as wages paid by the employer to the employee rather than tips paid by the customer.” 29 CFR 531.55(a) says the same for wage purposes — a compulsory charge “is not a tip” — and 531.55(b) puts such sums into “the employer’s gross receipts.”

So type it in and the tip line goes to nothing while the charge stays on the ledger where you can see it. On the worked example a $24.48 charge leaves $0 more to give. It is the same authority the salon tool uses on a salon’s service fee and the wedding vendor tool uses on “gratuity included”, and this is its sixth outing on the site. One thing the tool does differently here: if the charge lands below the published floor, it tops up to the floor rather than zeroing, because that remainder is still Emily Post’s figure and not ours.

The split is ours — all of it

Emily Post prices the table’s tip and stops there. No publication we would cite says whether the person who had a salad should help pay for the wine, and we are not going to invent one. So the split is a control with three stated rules, all three defensible, and the one you pick is printed on the ledger where the rest of the table can read it.

The arithmetic underneath the rule is not a judgment at all, and it is the one part of this site with a right answer. Shares are apportioned in whole cents by largest remainder — the method used to apportion legislative seats — so they sum to the check exactly rather than leaving a few cents on whoever happens to be holding the card. Three people splitting $169.60 get $49.88, $39.91, $79.81, and that adds up. Tax and tip are apportioned in the same proportion as each person’s share of the food, which is why the one expensive dish carries its own tax and its own tip rather than the table carrying it for them.

What this tool will not do

• It will not tell you a tip is required. Tipping in the US is customary, not owed, and every line is yours to change. It also will not lecture you about it in either direction — the low setting is on the ledger with its tag computed honestly, not hidden.
• It cannot read your check. It reports what you type. If a line on your bill is ambiguous — a “kitchen appreciation fee”, a “wellness charge” — the tool has no way to know whether it reaches anybody, and the honest place to ask is the restaurant.
• It does not decide who is right at your table. The three split rules produce genuinely different numbers, and the difference between them is a conversation about your friendship rather than a calculation. We show all three and label them ours.
• It is US-only. The percentages are American, service charges are treated very differently elsewhere, and in a great many countries the correct answer to all of this is a polite no.

Sources

• The Emily Post Institute — General Tipping Guide — the Wait Service (Sit Down), Wait Service (Buffet), Bartender and Take Out rows, including the words pre-tax in the first two.
• IRS — Tip recordkeeping and reporting — that a payment is a tip only if the customer voluntarily decides to pay it and determines the amount, and that auto-gratuities are treated as wages.
• 29 CFR 531.55 — Examples of amounts not received as tips — the federal wage rule that a compulsory service charge is not a tip and becomes the employer’s gross receipts.

Informational only, not professional advice. The Kindhow Scale is a published model, not a standard, and every line marked house judgment — which is the whole of the split — is our reasoning and nothing more. Nothing here is tax, legal or employment advice: the IRS and wage rules are quoted to explain what a charge on your check is, not to tell you, a restaurant or a server how to treat one. Last reviewed: August 2026. Scale version 1.0. Figures that come from a publication are re-checked against their source on a monthly cycle; when one moves, the version number moves with it.