The convention published by USATF Masters: 60 percent and over is Local Class, 70 and over Regional Class, 80 and over National Class, 90 and over World Class, and 100 percent approximates the world-record level for your age and sex. For most runners anything over 60 is a solid score and the 70s are competitive club level.
Your age standard is the open world standard for the distance divided by your age factor, and your age grade is that standard divided by your finish time. Worked example from the 2025 road tables: the men's marathon open standard is 2:00:35 and the age-60 factor is 0.8143, giving an age standard of 2:28:05, so a 3:30:00 finish grades at 70.5 percent. The age-graded time is simply your time multiplied by the factor.
The 2025 WMA/USATF road factors maintained by Alan Jones, approved by the USATF Masters Long Distance Running Council on January 10, 2025: the same current set behind the Howard Grubb and runbundle calculators. They cover ages 5 to 100 for both sexes across road 5K, 10K, half marathon and marathon, with marathon open standards of 2:00:35 for men and 2:09:56 for women.
parkrun grades against its own table, which its support pages describe as based on the WMA tables rather than identical, using the example of a 40:00 finish against a 20:00 best-known time scoring 50 percent. A strict WMA road calculator like this one can therefore land a point or two away from the age grade printed on your parkrun result.
Yes, rarely. A grade above 100 percent means the run beat the current age standard, which happens at the edges of masters running and is exactly what forces table revisions: WMA has updated its factors repeatedly, most recently the 2023 track set and the 2025 road set.
No. Age grading is a ratio against the best-known standard for your age and sex, not a percentile of participants: 70 percent does not mean you beat 70 percent of runners your age. It also ignores course difficulty and weather, so treat comparisons across different courses as rough.