Explanation
Add a tip and divide the bill
This calculator applies the entered tip percentage to the subtotal you provide, rounds the total tip to cents once, and splits the resulting total among a whole number of people. It does not infer tax, decide what a customary tip should be, or know whether a gratuity was already included.
T = round-cent(S × p/100); G = S + T; cents(G) = q × N + r
| S | entered bill subtotal before tip (USD) |
|---|---|
| p | tip rate as a percentage (percent (%)) |
| T | tip amount rounded once to cents (USD) |
| N | positive integer number of people (people) |
| G | subtotal plus settled tip (USD) |
$10.00 with a 15% tip, split 3 ways
| Bill | $10.00 |
|---|---|
| Tip | 15% |
| People | 3 |
| Result | $11.50 |
$10.00 + 15% tip ($1.50) = $11.50 for 3 people
$11.50 ÷ 3 people does not split evenly: 2 × $3.83 + 1 × $3.84 = $11.50
$100.00 with a 20% tip, split 4 ways
| Bill | $100.00 |
|---|---|
| Tip | 20% |
| People | 4 |
| Result | $120.00 |
$100.00 + 20% tip ($20.00) = $120.00 for 4 people
$120.00 ÷ 4 people = $30.00 each
$0.00 with a 1000% tip, 1 person
| Bill | $0.00 |
|---|---|
| Tip | 1,000% |
| People | 1 |
| Result | $0.00 |
$0.00 + 1,000% tip ($0.00) = $0.00 for 1 people
One person pays the whole $0.00
Diagram of this result
The total split into bill and tip, then divided by the number of people.
A bar shows the bill and the tip as parts of the total. Below it, the total divided by the number of people gives each share; when cents do not divide evenly, a few people pay one cent more so the shares add up exactly.
How leftover cents are assigned
After the tip is settled, convert USD total G to integer cents(G) and divide by people count N to obtain integer quotient q (base share in cents) and remainder r (0 ≤ r < N). Exactly N − r people receive q cents; the first r people receive q + 1 cents. The result reports only these two share groups and their counts, and their count-weighted sum equals cents(G) exactly.
Tip rounding happens once
The tip is calculated from the entered subtotal and percentage, then the total tip is rounded half-up to the nearest cent once. The settled tip is added to the subtotal before the split. Per-person rounding does not alter the total and cannot lose or create cents.
Assumptions and limits
Subtotal is nonnegative USD in whole cents, tip rate is 0%–1000%, and the number of people is 1–10000. The tip applies only to the supplied subtotal. No tax, fees, currency conversion, or already-included gratuity is inferred. The result is arithmetic allocation, not a recommendation about tipping.
Why can people have different shares?
A total in cents may not divide evenly by the number of people. To preserve the exact total, the first remainder shares are one cent higher; everyone else pays the base share. The count and both amounts are shown.
Does the calculator include tax?
No. The tip is calculated on the subtotal entered, and no separate tax amount is assumed or added. Include tax in your entered subtotal only if that is the basis you intend to use.
What if a gratuity is already on the bill?
The calculator cannot inspect a bill or detect an included gratuity. Check the bill first and avoid adding the same tip twice.
Rounding and allocation policy
Tip conventions vary by location and service; this calculator does not prescribe a customary rate. Its explicit policy is to settle the total tip once to cents and allocate any indivisible remainder as one cent to each of the first affected shares, preserving the exact total.