Running Pace Calculator
Calculate pace, time or distance, with split times for common race distances.
Please note: For general information only. This is not medical advice — speak to a doctor or registered dietitian before changing your diet, training or medication.
What the Running Pace Calculator does
Pace is time per unit distance — the number runners actually train by. This solves for whichever of pace, time or distance you are missing, and projects your finish times at standard race distances.
Formula
Pace = Time ÷ DistanceTime = Pace × DistanceDistance = Time ÷ PaceSpeed = Distance ÷ Time
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Calculate | one of 3 options | Yes | — |
| Distance | number | In some modes | Accepts more than 0. Shown Calculate is Pace (from distance and time), or Calculate is Time (from distance and pace). |
| Distance unit | one of 2 options | Yes | — |
| Hours | number | Optional | Accepts 0 or more. Shown Calculate is Pace (from distance and time), or Calculate is Distance (from time and pace). |
| Minutes | number | Optional | Accepts 0 or more. Shown Calculate is Pace (from distance and time), or Calculate is Distance (from time and pace). |
| Seconds | number | Optional | Accepts 0 or more. Shown Calculate is Pace (from distance and time), or Calculate is Distance (from time and pace). |
| Pace minutes | number | In some modes | Accepts more than 0. Shown Calculate is Time (from distance and pace), or Calculate is Distance (from time and pace). |
| Pace seconds | number | Optional | Accepts 0 or more, up to 59. Shown Calculate is Time (from distance and pace), or Calculate is Distance (from time and pace). |
How to use it
- Choose Calculate and Distance unit.
- Fill in the remaining inputs the form shows for your choice.
- Select Calculate.
Worked example
You run 10 km in 52 minutes 30 seconds.
- Distance
- 10
- Time
- 52:30
Pace 5:15 per km (8:27 per mile), speed 11.43 km/h. Marathon projection about 3:41:35.
Frequently asked questions
Are the race projections realistic?
They assume you hold the same pace, which gets harder as distance grows. For a marathon estimate from a 10K, expect to be slower than the linear projection.
How do I convert km pace to mile pace?
Multiply by 1.609. A 5:00/km pace is about 8:03/mile.
Method and sources
Method. Pace, time and distance are three views of one relationship: pace = time ÷ distance. Any two give the third.
Assumptions
- Pace is even across the whole distance, which is a modelling convenience rather than how anybody runs.
- Distance is accurate. GPS commonly over-reads on winding or built-up courses, which flatters pace.
Limitations
- This is arithmetic, not a prediction. Projecting a marathon pace from a 5 km time requires an endurance model and assumes training that supports the distance — neither of which is here.
- It says nothing about whether a pace is sustainable, safe or appropriate for the runner.
Sources
- None — pace is defined as time divided by distance — Not applicable. Recorded explicitly so the absent citation reads as deliberate rather than outstanding. There is no physiological claim here to source.