Split Bill by Ratio Calculator

Enter Calculation

Total amount

Ratios (e.g. 5:3:2 or 5,3,2)

Results

Total amount split among 3 group(s)

10,000

Sum of weights = 10

Group	Weight	Share (%)	Burden amount	Adjusted (sums to total)
1	5	50%	5,000	5,000
2	3	30%	3,000	3,000
3	2	20%	2,000	2,000

Sum of burden amounts	10,000
Rounding difference	0

Each "Burden amount" is rounded to the nearest whole unit independently, so the sum may differ from the total by a unit or two. The "Adjusted" column assigns the remainder to the last group so it sums exactly to the total.

What is the Split Bill by Ratio Calculator?

This tool divides a single total amount among several groups or people in proportion to a set of ratio weights. Instead of splitting a bill evenly, you decide that one group should pay more or less than another using weights such as 5:3:2. The math is purely proportional, so it works in any currency — the amount is treated generically and no conversion is applied.

A total bill split into proportional shares using ratio weights 5:3:2.

How to use it

Enter the total amount to be divided, then type the ratios as a list separated by colons or commas (for example 5:3:2 or 5,3,2). The number of weights equals the number of groups. Weights may be decimals (e.g. 1.5:2.5) and need not add up to 100 — only their relative proportions matter, so 5:3:2 gives the same result as 10:6:4.

The formula explained

Let the total be A and the weights be \(w_1\), \(w_2\), …, \(w_n\). First sum the weights: \(S = w_1 + w_2 + \dots + w_n\). Each group's raw share is \(A \times w_i / S\), and we round each share to the nearest whole unit (round half up). Because each share is rounded independently, the rounded shares may add up to slightly more or less than the total; the calculator also shows an "Adjusted" column that gives the remainder to the last group so the values reconcile exactly.

$$\text{Share}_i = \operatorname{round}\!\left( \text{Total} \times \frac{w_i}{\sum_{j} w_j} \right)$$

Each group's share equals the total times its weight over the sum of all weights.

Worked example

Total = 10000, ratios = 5:3:2. The weight sum is \(S = 10\). Group 1 gets

$$10000 \times \frac{5}{10} = 5000$$

group 2 gets 3000, and group 3 gets 2000. These sum back to 10000 exactly. With ratios of 1:1:1 on 10000, each raw share is 3333.33, rounding to 3333 each (total 9999); the adjusted column shows 3333, 3333, 3334 to total 10000.

FAQ

Do the weights have to be whole numbers? No. Decimals like 1.5:2.5 are allowed; only the ratio between weights matters.

Why don't the shares always add to the total? Each share is rounded to the nearest whole unit on its own, which can leave a small remainder. The adjusted column fixes this by giving the difference to the last group.

What if all weights are zero? The split is undefined because the weight sum is zero; enter at least one positive weight.