PB predictor and pace calculator

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 marathon course models

• Estes Park Marathon and Half Marathon

  Modelled energy change -4.6%.

• Montana Marathon (Billings)

  Modelled energy change -2.5%.

• Windermere Marathon (Spokane)

  Modelled energy change -0.5%.

• Reims Champagne Run Marathon

  Modelled energy change -0.4%.

• Maratona do Funchal (Funchal Marathon)

  Modelled energy change -0.4%.

• Generali Genève Marathon

  Modelled energy change -0.3%.

• Belfast City Marathon

  Modelled energy change -0.1%.

• Hoag OC Marathon Running Festival

  Modelled energy change -0.1%.

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.

See the gradient-normalisation methodology →

Find a course that suits your target

• Flattest marathons

  Courses with the lowest GAP penalty in our gradient model.