# Bill split ratio calculator: split by shares or ratio

Canonical URL: https://www.evenoutapp.com/tools/split-by-shares-calculator
Updated: 2026-10-06

A bill split ratio gives each person a number of shares. Add the shares, divide the total by that sum to get the price of one share, then multiply by each person's shares. A $1,500 cabin with stays of 7, 5 and 3 nights is 15 shares at $100, so the three people pay $700, $500 and $300.

Key points:
- A ratio is shares in other notation: 3:2:1 means 3, 2 and 1 shares, so type 3, 2 and 1.
- Price of one share = total ÷ all the shares added together. Each person pays their shares times that price.
- Half shares work. A child at 0.5 pays half of an adult at 1 share.
- Shares can add up to anything, unlike percents, which must add up to 100. Amounts are exact to the cent.

## When to split by shares or ratio

Split by shares when people's parts are unequal and you know them as counts, not as percents. Nights stayed in a rental, adults and children at a shared dinner, or rooms in a house all work. A ratio such as 3:2:1 is the same thing in different notation: each number is a number of shares, so you type 3, 2 and 1.

## How the calculator works

It adds up all the shares, divides the total by that sum to get the price of one share, then gives each person their shares times that price. The shares can add up to anything: 7, 5 and 3 make 15 shares, and 3, 2 and 1 make 6. That is the difference from the [percentage split calculator](https://www.evenoutapp.com/tools/percentage-split-calculator), where the parts should add up to 100.

## Worked example: a $1,500 cabin by nights

Say three people share a $1,500 cabin and stay 7, 5 and 3 nights. Use the nights as shares. They add up to 7 + 5 + 3 = 15 shares, so one share is $1,500 ÷ 15 = $100.

| Person | Nights (shares) | Pays |
|---|---|---|
| Person 1 | 7 | $700 |
| Person 2 | 5 | $500 |
| Person 3 | 3 | $300 |

Dividing by the number of people instead would charge $500 each. That is $200 too little for the person who stayed 7 nights and $200 too much for the person who stayed 3. For other costs on a rental, see [how to split a vacation rental fairly](https://www.evenoutapp.com/guides/how-to-split-a-vacation-rental).

## Half shares and household shares

A share can be a fraction. A child counted at half an adult is 0.5 of a share. Say $840 of groceries for a weekend is shared by three households. The first has two adults and two children (1 + 1 + 0.5 + 0.5 = 3 shares), the second is a couple (2 shares) and the third is one person (1 share). That is 6 shares, so one share is $840 ÷ 6 = $140, and the households pay $420, $280 and $140.

Each of the six boxes can stand for a person or for a whole household.

## Turning a ratio into percents

To see each person's percent, divide their shares by the total shares and multiply by 100.

| Ratio | Total shares | Percent of each person |
|---|---|---|
| 3:2:1 | 6 | 50%, 33.3% and 16.7% |
| 7:5:3 | 15 | 46.7%, 33.3% and 20% |
| 2:1 | 3 | 66.7% and 33.3% |

Percents also work as shares. Enter 60 and 40 and the total is 100 shares, so one share is 1% of the bill.

## Where the cents go

The calculator does not build each amount from the rounded share price. Say $1,000 is split across 1.5, 1 and 0.5 shares, which is 3 shares. One share is $333.333 and so on, shown as $333.33, and the exact amounts are $500.00, $333.333 and $166.667. Rounded down they are $500.00, $333.33 and $166.66, which add up to $999.99, so one cent is left. It goes to the amount that lost the most in rounding, the third, which becomes $166.67 and brings the total to $1,000.00. The displayed share price times 3 shares is $999.99, a cent short, which is why the calculator works from the exact amounts.

## Common mistakes

- **Dividing by people instead of shares.** $1,500 ÷ 3 is $500 each and ignores the nights.
- **Typing the ratio's total as a share.** For 3:2:1, type 3, 2 and 1, not 6.
- **Counting different things in different boxes.** Every box has to count the same unit, nights for everyone or adult equivalents for everyone, not nights for one person and people for another.

## Using shares in EvenOut

EvenOut's "Shares" method in the "How to split" sheet works the same way. Type each person's shares and their dollar share shows under their name, along with the price of one share. EvenOut splits are accurate to the cent there too, and remainder cents are shared out, not lost. The other methods and their formulas are set out in [the formulas for splitting bills](https://www.evenoutapp.com/guides/formula-for-splitting-bills).

## Frequently asked questions

### What is the difference between a ratio and a percent split?

A percent split must add up to 100, while shares add up to whatever they add up to. That makes shares easier to keep current. If a fourth person joins the cabin with 2 nights, you type 2 in the next box and nobody else's number changes. With percents, every person's percent would have to be worked out again.

### Can I give a couple double the share of a single person?

Yes. Give the couple 2 shares and each single person 1. A $300 bill over a couple and two singles is 4 shares at $75, so the couple pays $150 and each single person pays $75.

### How do I handle a fixed fee like a cleaning charge?

Run the shares for the part that depends on nights, then split the fixed fee equally and add the two. On the cabin example, a $120 cleaning fee is $40 each, so the three people pay $740, $540 and $340, which add up to $1,620.

### What if there are more than six people?

Put households in one box. A family of four is 4 shares, or fewer if some are children at half shares. Each household then splits its own amount however it likes.