BillSplit

The arithmetic is usually right

The inputs are what go wrong.

Somebody fronts every bill, then reconstructs it later from a phone note. The tax gets dropped. The discount lands on the wrong person. An entire stop is forgotten. BillSplit starts from the receipt itself and apportions every charge to whoever actually ordered it.

Exact
no floating point
Traceable
to the line item
Any size
two people or fifty

NORTH POINT KITCHEN

Order 4471 · 19:42

  • 2× Charcoal flatbread24.00
    Ada · Rae
  • 1× Grilled sea bass32.50
    Mira
  • 1× Summer salad18.00
    Tom
  • 3× Yuzu soda13.50
    Ada · Mira · Tom
  • Subtotal88.00
  • Service charge 10%8.80
  • Tax 9%8.71
  • Member discount−13.20
TOTAL92.31

Settles to

  • Mira38.81
  • Tom23.60
  • Ada17.31
  • Rae12.59
SETTLED

Four allocations. They sum to 92.31 exactly.

The part done by hand

A discount is not a flat deduction.

Split that 13.20 discount evenly and everyone saves 3.30. But Mira ordered 37.00 of the 88.00 subtotal and Rae ordered 12.00 — so an even split quietly moves money from the person who ordered least to the person who ordered most.

Rae owesSplit evenlyPro-rataon a 12.00 order11.0912.59

Exactly a dollar fifty, on one line of one bill, in a direction nobody notices and nobody queries. Across seven receipts it stops being a rounding curiosity and starts being the reason the person who paid is quietly out of pocket.

How it works

  1. 01

    Capture the bill

    Photograph it, or type it in. Manual entry is a first-class path, not an afterthought — extraction will never be perfect, so the fallback has to be good.

  2. 02

    Say who had what

    Tap the people who shared each line. One tap for everyone. The next item defaults to the last selection, because consecutive lines usually belong to the same person.

  3. 03

    Read the answer

    Tax, service and discounts apportioned to what each person actually ordered. Tap any figure to see the lines and documents underneath it.

Why the numbers hold

Built to be argued with.

The point is not that it computes a number. The point is that when somebody disputes theirs, the number holds.

Nothing rounds early
Every intermediate value is an exact fraction — a whole-number numerator over a whole-number denominator, never a decimal approximation. A fare split three ways stays exact until the final settlement, so the cents cannot quietly go missing along the way.
Every figure traces to a document
No total is an orphan. Each one resolves to the receipt and the line item that produced it, which is what survives somebody asking why they owe this much.
A bad parse fails loudly
Extracted receipts are checked against their own subtotal and total before you ever see them. One that does not add up is flagged, never silently corrected — a receipt you can distrust is worth more than one quietly patched.