Training for a fall race? Enter any two of distance, time, and pace — get the third plus full race-split tables instantly.

Running Pace Calculator — Pace, Speed, Time & Race Splits | Free Online Tool

Running Pace Calculator: Pace, Speed, Time & Splits in Seconds

Enter any two of distance, time, or pace and get the third instantly — in min/mile, min/km or mph. Then plan race day with mile-by-mile split tables and finish-time predictions from your latest race.

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Tip: run a 10K in 50:00 and your pace is about 8:03 per mile (5:00 per km). A marathon at a steady 8:00/mi finishes in 3:29:36.

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Even splits keep it simple and fast — banking time early almost always backfires after mile 20. Print the table or screenshot it for race day.

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Predictions use the Riegel formula (T2 = T1 × (D2/D1)1.06) — the standard coaches and race sites use. It assumes similar fitness and conditions.

100% private

All calculations run in your browser. Your training data never leaves your device.

No signup needed

No account, no app — open it on your phone and get your pace in seconds.

Free forever

Unlimited pace, split and prediction calculations, every feature included.

How to use the pace calculator

  1. 1Pick what you know

    Choose any two — distance + time, distance + pace, or time + pace. Tap a race preset (5K, 10K, half marathon, marathon) or type a custom distance.

  2. 2Set your pace unit

    Switch between min/mile, min/km and mph with one tap — perfect for treadmill runners and metric training plans alike.

  3. 3Plan race day

    Open Race Splits for a mile-by-mile (and km-by-km) goal-time table, or Time Predictor to see what your last race says about your next one.

Why runners keep this tab open

Any-two-of-three solving

Know your time and pace but not the route length? Or the distance and target time? It fills in the missing piece either way.

Mile and metric splits

Full split tables per mile and per kilometer with cumulative times — screenshot them and tape one to your wrist for race day.

Riegel predictions

Enter a recent race and get data-backed finish estimates for 5K through marathon using the formula coaches trust.

mph for treadmills

Toggle to mph and the calculator speaks treadmill — set the belt to exactly the speed your plan demands.

True race distances

Uses official 26.2 / 13.1 mile courses (42.195 / 21.0975 km), so marathon math comes out right to the second.

Phone-friendly at the track

Big touch targets and large results you can read mid-workout — no squinting at tiny text between intervals.

Running pace questions, answered

What is a good running pace?
It depends on the distance and your fitness. For context: a 10K in 50:00 is about 8:03/min per mile (5:00/km) — a solid recreational pace. Breaking 4 hours in the marathon needs roughly 9:09/mi, while a 3:30 marathon needs about 8:01/mi. Compare against your own history, not strangers.
How do I convert min/mile to min/km?
Multiply min/mile by 0.6214 (or divide by 1.609). So 8:00/mi is 4:58/km. This calculator does every conversion for you — pace in min/mi, min/km, mph and km/h all appear together.
Should I run even splits or negative splits?
Research and race results both favor even splits for most runners: the same pace every mile is the fastest way through the distance. Negative splits (second half faster) work for experienced racers; positive splits — going out too fast — are the classic marathon mistake.
How accurate is the finish-time predictor?
It uses the Riegel formula, the industry standard: T2 = T1 × (D2/D1)1.06. It is usually within a few percent when fitness and conditions are similar — treat it as a target range, not a guarantee, especially jumping from 10K to marathon.
Why is my GPS watch pace different from the calculator?
GPS watches measure the path you actually ran — weaving, tangents, signal wobble — while the calculator uses the exact course distance. On a certified course, trust the course distance for your official pace.
What pace do I need for a sub-4-hour marathon?
About 9:09 per mile (5:41/km). For sub-3:30 you need about 8:01/mi. Plug your goal into the Race Splits tab to get the mile-by-mile plan.

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