How to Calculate Cumulative Percentage in Excel (Pareto)
A cumulative percentage needs two anchored formulas stacked together — a running SUM, then a divide by the grand total — and both drift when rows move. Here's why, and the one-click way to get a clean Pareto / 80-20 curve.
Last updated: August 2026
| Value (sorted desc) | Cumulative % | |
|---|---|---|
| 50 | → | 50% |
| 30 | → | 80% |
| 20 | → | 100% |
Why two anchored formulas are painful
A cumulative percentage is really two jobs. First a running total, =SUM($B$2:B2) with its half-absolute range; then divide that by the grand total, =SUM($B$2:$B$99), and format as a percentage. Both formulas depend on fixed row positions, so inserting, deleting or sorting rows makes the ranges drift and the climbing shares go wrong — and you need them both correct at once for the curve to reach a clean 100%.
The 1-click way — Tellsheet's Cumulative Percent
Sort the column descending first, select it, and run Cumulative Percent. It combines Running Total and Percent of Total in one pass — each row's cumulative sum as a percentage of the grand total — so the last row lands on 100% and the column reads straight off as a Pareto / 80-20 / ABC curve. No anchored formulas to maintain. Pairs with Percent of Total and Running Total.
Frequently asked questions
How do I calculate cumulative percentage in Excel?
Manually you build a running total, then divide each row by the grand total. Cumulative Percent does both at once in one click.
How do I make a Pareto or 80-20 curve?
Sort the column largest to smallest first, then run Cumulative Percent — the rising share column is your Pareto curve.
Why are the manual formulas painful?
Two anchored formulas both depend on fixed rows, so inserting, deleting or sorting drifts the ranges and breaks the percentages.
Does the last row reach 100%?
Yes — the running sum over the true grand total means the final row hits 100% before rounding.
Related Excel guides
Build a Pareto curve in one click
Cumulative Percent gives the running share of the total on every row — Running Total and Percent of Total combined, no anchored formulas.
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