Compares your time with the best possible for your age and sex, using the official 2025 road-running age-grading standards.
| Level | Age grade | Time needed | Pace |
|---|
| Distance | Split | Cumulative |
|---|
Pace and speed are two ways of describing the same thing: pace is time per unit distance (like minutes per kilometre), and speed is its reciprocal (distance per unit time, like kilometres per hour) — enter either one and the calculator handles the conversion both ways.
A pace entered as minutes:seconds is first converted to total seconds internally, then scaled between miles and kilometres using the exact 1.609344 km per mile, so switching between imperial and metric pace always stays mathematically consistent.
Race time projections multiply your pace by a target distance, which is how the calculator estimates your finish time for a 5K, 10K, half marathon, or marathon based on a pace you're already running or aiming for. Switching between entering a pace, a speed or a finish time clears the field first, so you never mix formats.
Add your age and sex to get an age grade: your time compared with the best possible for your age over the same distance, using the 2025 road-running age-grading standards. The level table shows the times you would need for 60%, 70%, 80% and 90% at your age.
Enter your pace in one unit and the calculator converts it to the other automatically, using the exact 1.609344 km-per-mile conversion factor applied to the underlying seconds-per-unit-distance value.
By multiplying your pace by the race distance: 5 km, 10 km, 21.0975 km for a half marathon or 42.195 km for a marathon. You can also enter a finish time instead, and the calculator works out your pace from it.
Pace is time per distance (e.g. 5:00 per km); speed is distance per time (e.g. 12 km/h) — they're mathematical reciprocals of each other, and you can enter either one.
To prevent accidentally combining a pace string (like 5:30) with a speed number (like 12) in the same field, which would produce a meaningless result. Switching modes gives you a clean field for the correct format.
Age grading compares your time with the best time possible for your age and sex over the same distance. Age grade = age standard ÷ your time. As a rough guide, 60% is local class, 70% regional class, 80% national class and 90% world class. The open-equivalent time is what your performance would be worth at peak age. This calculator uses the 2025 road-running age-grading standards (Alan Jones and Tom Bernhard, approved by the USATF Masters Long Distance Running Council).
About 1 kcal per kilogram of body weight per kilometre, and this is fairly constant across running speeds. A 70 kg runner uses roughly 350 kcal over 5 km. Enter your weight to get your own estimate.
