# Bill Split Calculator

> Adds an optional tip percentage to a bill and divides the total equally among a number of people, reporting the tip, the total and each person's share.

- Calculator id: `bill-split` · Category: Everyday Life (`everyday`) · Tool name: `calculate_bill_split`
- Canonical page: https://tttkmbb.com/everyday/bill-split · This document: https://tttkmbb.com/everyday/bill-split.md · JSON definition: https://tttkmbb.com/everyday/bill-split.json

## Purpose

Adds an optional tip percentage to a bill and divides the total equally among a number of people, reporting the tip, the total and each person's share.

**Use when:** A restaurant bill, taxi fare or shared purchase must be divided equally among several people, with or without a tip.

**Do not use when:** Shares are unequal (itemised bills), you only need the tip amount for one payer (use tip), or the cost is a trip's fuel (use fuel-cost).

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `total_bill` | number |  | required | Bill total before tip, in your currency. (min 0, max 100000000) |
| `people` | integer |  | required | How many people share the bill equally. (min 1, max 1000) |
| `tip_percent` | number | % | optional, default 0 | Tip as a percentage of the bill (15 means 15 %). (min 0, max 100) |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `tip_amount` | number |  | total_bill × tip_percent / 100. |
| `total_with_tip` | number |  | total_bill + tip_amount. |
| `per_person` | number |  | total_with_tip / people. |
| `bill_per_person` | number |  | total_bill / people. |
| `tip_per_person` | number |  | tip_amount / people. |

## Formula

`tip_amount = total_bill × tip_percent / 100; total_with_tip = total_bill + tip_amount; per_person = total_with_tip / people`

## Data Sources

- Gratuity – customary tipping rates by country (Wikipedia) — https://en.wikipedia.org/wiki/Gratuity (reference, retrieved 2026-09-23)

Data freshness: `static`. Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output.

## API

- `GET https://tttkmbb.com/api/v1/calculate/bill-split?total_bill=…&people=…`
- `POST https://tttkmbb.com/api/v1/calculate/bill-split` with JSON body `{"inputs": {…}}`
- Response: unified envelope (`success`, `request`, `result.values`, `result.units`, `sources`, `freshness`, `timestamp`, `next_actions`, `links`); see https://tttkmbb.com/docs/response-format.md
- Schema: https://tttkmbb.com/api/v1/calculators/bill-split · OpenAPI operationId `calculate_bill_split` in https://tttkmbb.com/openapi.json
- Authentication: none. Rate limit: fair use, see https://tttkmbb.com/docs/rate-limits.md.

## MCP

- Server: `https://tttkmbb.com/mcp` (Streamable HTTP, JSON-RPC 2.0, no auth)
- Tool:  `run_calculator` with `{"calculator_id": "bill-split", "inputs": {…}}`

## Example

- 120 bill, 4 people, 15 % tip: inputs `{"total_bill":120,"people":4,"tip_percent":15}` → `{"tip_amount":18,"total_with_tip":138,"per_person":34.5,"bill_per_person":30,"tip_per_person":4.5}`
- 87.50 bill, 3 people, no tip: inputs `{"total_bill":87.5,"people":3}` → `{"tip_amount":0,"total_with_tip":87.5,"per_person":29.17,"bill_per_person":29.17,"tip_per_person":0}`

```
GET https://tttkmbb.com/api/v1/calculate/bill-split?total_bill=120&people=4&tip_percent=15
```

## Limitations

Shares are unequal (itemised bills), you only need the tip amount for one payer (use tip), or the cost is a trip's fuel (use fuel-cost). All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**Should the tip be calculated before or after sales tax?**

Customs vary; in the US the tip is commonly computed on the pre-tax amount. Enter whichever base you want as total_bill.

**The per-person amount does not multiply back exactly to the total.**

Shares are rounded to 2 decimals; a difference of a few cents is rounding and one person can cover it.

## Related

- [Tip Calculator](https://tttkmbb.com/finance/tip.md) — Tip amount and total for a single payer.
- [Fuel Cost Calculator](https://tttkmbb.com/everyday/fuel-cost.md) — Share a trip's fuel cost between passengers.