WMA Age-Grading Percentage Explained

“WMA percentage” is what many race results and running clubs call the age-graded score, after World Masters Athletics, the federation whose tables the calculation rests on. Same arithmetic, different label. Enter the standard for your age and your race time:

Two numbers people mix up

Term	Depends on	Typical value
Age factor	age, sex, distance — never on your race	0.8886 for a man of 50 at 10K
WMA percentage / age-graded score	your finishing time, via the standard	70.7% for that man running 42:00

The factor is a property of the table; the percentage is a property of your race. They connect through one line: age standard = open standard ÷ age factor, and then percentage = standard ÷ your time × 100. Race software usually shows only the percentage, which is why the factor turns up mainly in the tables themselves and in the table page.

WMA compiles, USATF approves

The system began with World Masters Athletics — under its old name, the World Association of Veteran Athletes — and USATF still describes the tables as researched and compiled by that federation. The road tables American races actually score with are then approved by the USATF Masters Long Distance Running Council, which signed off on the current 2025 edition on January 10, 2025. So a US race result and a WMA percentage are the same figure arriving through two committees.

Your percentage can move while your time stands still

This is the part that surprises masters runners: revise the table, and every past result is rescored. Between the 2020 and 2025 road editions the men’s standards barely budged — the 10K open standard stayed at 26:24, the marathon went from 2:01:39 to 2:00:35 — while the women’s moved a lot:

Women’s open standard	2020	2025
5K	14:44	13:54
10K	29:43	28:46
Marathon	2:14:04	2:09:56

The standards come from the best times recorded at each single age, so the women’s road records of the early 2020s raised the bar for every woman in the table. In practice: a 50-year-old woman who ran 10K in 45:00 scored 74.9% under the 2020 tables and 72.5% under the 2025 ones. She did not get slower; the reference did.

Two habits follow. Quote the table edition alongside any percentage you are proud of, and compare your own scores across years only when they were computed on the same edition — otherwise a “decline” may just be a revision. What the resulting number means in words is on the age grading calculator, and translating it to another age or sex is the job of the equivalent-time calculator.