Cumulative Percentage Calculator
Turn a list of values into a running cumulative total and the cumulative percentage of the grand total at each step.
How it works
Cumulative % at step k = (sum of first k values) ÷ (total of all values) × 100
A cumulative percentage adds each value to a running total and expresses that total as a share of the overall sum. It always ends at 100%. This is the backbone of Pareto (80/20) analysis and ogive curves — reading down the column shows how quickly the first few categories account for most of the whole.
Worked example
For 10, 20, 30, 25, 15 the total is 100. The running totals are 10, 30, 60, 85, 100, so the cumulative percentages are 10%, 30%, 60%, 85% and 100%.
Frequently asked questions
What is a cumulative percentage used for?
It shows how a running total builds toward the whole — central to Pareto charts, frequency ogives and progress tracking, where you want to know what share the top items cover.
Should I sort the values first?
For a Pareto analysis, sort from largest to smallest so the curve rises fastest and the "vital few" stand out. For a time series, keep the natural order.
Why must the values not sum to zero?
The cumulative percentage divides by the grand total. If everything sums to zero the share is undefined, so the calculator asks for a non-zero total.
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This calculator is for educational purposes. Double-check important results before acting on them.