Excel Percent Difference Between Two Numbers

What this does

Two different calculations share this name. Percentage change measures B against a starting value A, so its sign shows the direction and swapping the values changes the result. Percentage difference compares two values where neither is the reference — two quotes, two measurements, two stores — so it divides the absolute gap by the average of both and gives the same result in either order. Growth, increase and decrease questions want percentage change; comparisons between two peers usually want the symmetric version. The same idea underpins a lot of everyday Excel work, so the few minutes spent getting it right here pay back across every sheet you build afterwards. Treat it as a pattern, not a one-off, and it stops being something you look up and starts being something you reach for. Treat “excel percent difference between two numbers” as a small repeatable workflow rather than a one-off click you hope to remember next time. Use a small test block before the live file, so any surprise in the affected cells shows up while it is still harmless. When a formula is involved, keep the inputs labelled beside it, reference cells instead of typing values, and apply number formatting only after the result checks out. That turns a calculation you can defend to a CFO or an auditor into a method you can reuse, explain, and defend when the workbook leaves your screen.

A worked example

A2 = 80 and B2 = 100. The change from 80 to 100 is =(B2-A2)/A2 = 25%, but from 100 to 80 it is -20%. The symmetric percentage difference is =ABS(A2-B2)/AVERAGE(A2,B2) = 20 ÷ 90 = 22.2%, whichever value comes first. Mixing up the two definitions changes the number in a report. Choosing the formula that matches the question — growth from a baseline or a gap between equals — keeps comparisons consistent. Check the referenced cells, argument order and result type in your workbook. Start with the worked example before changing an input, then compare the changed result with the calculation you expected. An error value or a result of a different type is a reason to inspect the inputs and arguments.

In Google Sheets

Google Sheets support for this task has not been verified. Check the function, arguments and workflow in the target product before transferring the example. Matching formula notation does not establish identical behaviour. Keep this page bookmarked for the next time the same question comes up. Better still, repeat the steps once in your own workbook — doing it yourself is what turns a copied answer into something you remember. For “excel percent difference between two numbers”, keep the input cells and the result visible while you check the formula in Excel. Follow the worked example and change one input at a time. The steps explain the workbook calculation; this page does not run a live calculator for that task.

Common mistakes

• Dividing by the wrong value: for a percentage change the baseline goes in the denominator.
• Using percentage change for two peers, where swapping them changes the answer.
• Multiplying by 100 and also formatting as Percentage, which shows 2500% instead of 25%.
• Using the symmetric formula for values with opposite signs, where their average no longer describes their size.

Frequently asked questions