Running Pace Calculator: Goal Time to Pace, Pace to Finish, Race Predictor
Three calculators in one page: what pace a goal time needs, what finish time a pace gives, and what your recent race predicts at other distances. Runs in your browser, nothing is sent anywhere.
How the calculator works
Pace = time ÷ distance, using 42.195 km for the marathon, 21.0975 km for the half, 10 km and 5 km, and 1.609344 km per mile. The predictor uses the Riegel formula T2 = T1 × (D2 ÷ D1)1.06, the same formula the plan generator uses to set training paces from a recent race. Predictions to the marathon assume you do the long runs; without them the real result is slower.
For printed tables see the marathon pace chart, half marathon pace chart, 10K and 5K charts, or the running pace chart from pace to finish time.
Turn the goal into a training plan
Same engine as every plan on this site, but with your race date, your run days and your longest recent run. Prints to PDF, exports to your calendar. No signup.
Frequently asked questions
What pace do I need for a 4 hour marathon?
9:09 per mile or 5:41 per km. See the 4 hour marathon pace page for splits.
How accurate is the Riegel race predictor?
It is a statistical fit, not a measurement. It works best between neighbouring distances (10K to half, half to marathon) and for runners whose training matches the target distance. Treat marathon predictions from a 5K as an upper bound.
Does the calculator work in kilometers?
Yes. Every result shows both per-mile and per-km pace, and the pace-to-time calculator accepts either unit.