PB predictor and pace calculator
Estimate a finish time from current form, or calculate exact pace, splits and a manual cutoff plan.
Pace charts by distance
Read a finish-time table, choose a target and print or share your kilometre or mile splits.
Performance prediction
Enter a recent result and the race you are targeting. We convert your current form to an equivalent finish time. Course energy estimates help compare terrain; they do not yet provide a validated adjustment to your finish time.
Pace, splits and cutoff arithmetic
Convert a target time or pace into an even-pace plan for distances up to 1,000 km. These figures are arithmetic, not a prediction of what you can achieve. The separate predictor above estimates equivalent performance from a recent result.
Compare half marathon course models
Estes Park Marathon and Half Marathon
Modelled energy change -9.9%.
Montana Marathon (Billings) Half Marathon
Modelled energy change -4.2%.
Bozeman Half Marathon & 10K
Modelled energy change -4.2%.
Spurs Austin International Half (fka 3M Half Marathon)
Modelled energy change -2.3%.
Jack & Jill's Downhill Marathon & Half Half Marathon
Modelled energy change -1.5%.
Trieste Spring Run Half Marathon
Modelled energy change -1.5%.
St. Croix Crossing Half Marathon
Modelled energy change -1.0%.
Generali Genève Marathon Half Marathon
Modelled energy change -1.0%.
Why a course-adjusted predictor
Generic predictors assume every course is flat. When a race has a verified GAP profile, this tool uses that measured gradient profile so a target with 300 m of climb is predicted slower than a pancake-flat PB course.