Ratio to Percentage

A ratio compares two quantities, like 2:3, but it does not directly tell you what slice of the whole each part takes. Converting a ratio to percentages does exactly that — it rephrases "two parts to three parts" as "40% and 60% of the total." This tool handles a two-part ratio and updates as you type.

The formula

First add the parts to find the total, then divide each part by that total and multiply by 100:

total = A + B
percent of A = (A ÷ total) × 100
percent of B = (B ÷ total) × 100

For the ratio 2:3, the total is 2 + 3 = 5. The first part is (2 ÷ 5) × 100 = 40% and the second is (3 ÷ 5) × 100 = 60%. Because both parts are divided by the same total, the percentages always add up to 100% — a built-in check that your conversion is correct.

A worked example

Imagine a total split between two groups in the ratio 2:3. The total number of shares is 2 + 3 = 5. The first group's share is 2 out of 5, which is 40%, and the second group's share is 3 out of 5, which is 60%. If the actual total were 200 units, the first group would hold 40% × 200 = 80 units and the second 60% × 200 = 120 units — and 80 + 120 returns the original 200, confirming the split.

Ratios as chart data

Percentages from a ratio are exactly what a composition chart needs. A two-part ratio like 2:3 becomes a pie chart with two slices of 40% and 60%, the full circle representing the combined whole. Converting the ratio first means every slice is already scaled to sum to 100%, so the pie is guaranteed to close cleanly.

With your percentages in hand, the pie chart maker draws and exports the pie or donut, or use make a chart to show the two parts as bars instead. To convert a single fraction the same way, try the fraction to percentage tool.