Miles and kilometres stay convertible
- Pace /km
- 5:00
- Pace /mi
- 8:03
A 10 km effort entered as 6.213712 mi still resolves near 5:00 /km. The converter uses 1.609344 km per mile; rounding to whole seconds can nudge the displayed pace by a second.
Sports
Running Pace Calculator
Calculate pace, finish time or distance. Build a constant-pace split plan for 5K, 10K, half marathon or marathon and share it.
Formula and sources updated · Data sources · 3View algorithm, constants and default inputs (JSON)
Total time (min)
Cumulative splits
Swipe horizontally to see more
| Distance (selected split unit) | Elapsed time |
|---|---|
| 1.000 | 0:05:00 |
| 2.000 | 0:10:00 |
| 3.000 | 0:15:00 |
| 4.000 | 0:20:00 |
| 5.000 | 0:25:00 |
| 6.000 | 0:30:00 |
| 7.000 | 0:35:00 |
| 8.000 | 0:40:00 |
| 9.000 | 0:45:00 |
| 10.000 | 0:50:00 |
About this calculator
Choose pace, finish time or distance. Enter the other two values. Splits assume a constant pace and include the final partial segment. Share a plan as text, an image or a link. For a simple pace calculation, enter distance and elapsed time in pace mode. The same tool can solve for finish time or distance and show splits.
Recomputed from this page's implementation at build time · checked 2026-10-27
Pace, finish time and distance are the same equation solved three ways
A running plan is one identity — distance × pace = time — with three solve modes and a split table that must include the final partial segment. The trap is unit mixing: minutes-per-mile against kilometres quietly invents a different race.
- 5:00 10 km in 50:00 pace mode
- 0:50:00 10 km at 5:00 /km finish-time mode
- 10.000 50:00 at 5:00 /km distance mode
Three modes, one identity
Half marathon at a steady pace
- Finish
- 1:56:02
Distance × pace fills finish time. Splits still assume the pace is constant; they are a planning grid, not a fatigue model.
Partial final split is kept
- Pace /km
- 5:30
When distance is not an integer number of split units, the table still emits the last partial segment instead of dropping leftover metres.
Plans the page will not invent
-
You typed
- mode
- pace
- distance
- 0
- unit
- km
- hours
- 0
- minutes
- 50
- seconds
- 0
- paceMinutes
- 5
- paceSeconds
- 0
- paceUnit
- km
- splitUnit
- km
It answeredinputErrorZero distance cannot define a pace
Pace is time divided by distance. A zero distance would be infinite pace; the page rejects it.
-
You typed
- mode
- distance
- distance
- 10
- unit
- km
- hours
- 0
- minutes
- 0
- seconds
- 0
- paceMinutes
- 5
- paceSeconds
- 0
- paceUnit
- km
- splitUnit
- km
It answeredinputErrorZero time cannot define a distance from pace
With no elapsed time, distance-from-pace has nothing to integrate. The inputs must describe a real effort.
Assumptions inside the splits
- Constant-pace splits
- The split table assumes an even pace. It does not model hills, wind, or negative splits; those belong in a training plan, not in this identity.
- Second-level rounding
- Displayed pace rounds to whole seconds. Converting km ↔ mi can therefore move the projected finish by a second even when the underlying ratio is unchanged.
- Prediction is a sibling page
- Riegel-style race prediction lives on the marathon pace predictor. This page stays invertible: any two of pace, time and distance recover the third.
Against a race predictor
-
Omni Pace Calculatorchecked 2026-10-27
- Theirs
- Pace/time/distance solving with unit toggles and explanatory article chrome.
- Here
- Three explicit modes, cumulative splits including the last partial segment, and shareable URL state without an account wall.
Why they built it that wayOmni’s pace tool is a common SERP neighbour and also offers solve-any-variable behaviour.
Runners share workouts. Anonymous URL restoration and a partial final split are the practical differences once the identity itself matches.
Pace mode, 10 km in 50:00 → 5:00 /km. Switch to time mode with 10 km and 5:00 /km → finish 0:50:00. Switch to distance mode with 50:00 and 5:00 /km → 10 km.
Checked pace/time/distance invertibility on the shared engine and compared km/mi using the 1.609344 factor declared in the formula note · impl aab14703
Method and assumptions
p = t / D; t = D × p; D = t / p; 1 mi = 1.609344 km Choose pace, finish time or distance. Enter the other two values. Splits assume a constant pace and include the final partial segment. Share a plan as text, an image or a link. The references provide context and limitations. They do not validate this page’s illustrative multipliers, lookup values or predictions.
Data sources
- Riegel (1981) — Athletic records and time-distance extrapolation
- NIST — Guide for the Use of the International System of Units (SI)
- World Athletics — Competition and Technical Rules (road race distances)
The references provide context and limitations. They do not validate this page’s illustrative multipliers, lookup values or predictions.
Disclaimer
These calculators give general mathematical results. They suit study, planning and estimation — verify anything that feeds a graded submission, a published figure or a financial commitment.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
p = t / D; t = D × p; D = t / p; 1 mi = 1.609344 km
- D
- Distance (km)
- t
- Total time (min)
- p
- Pace per kilometre (min/km)
Choose pace, finish time or distance. Enter the other two values. Splits assume a constant pace and include the final partial segment. Share a plan as text, an image or a link.
Frequently asked questions
How do I calculate pace, finish time or distance?
Choose pace, finish time or distance. Enter the other two values. Splits assume a constant pace and include the final partial segment. Share a plan as text, an image or a link.
Which inputs and limits apply to Running Pace Calculator?
Use the units shown beside each field. These are form limits, not recommended settings. Distance (Kilometres): 0–500; Distance (Miles): 0–310.6855961187; Distance (Metres): 0–500,000; Time — hours: 0–1,000 h; Time — minutes: 0–60,000 min; Time — seconds: 0–60,000 s; Pace — minutes (Kilometres): 0–120; Pace — minutes (Miles): 0–194; Pace — seconds: 0–59 s p = t / D; t = D × p; D = t / p; 1 mi = 1.609344 km Choose pace, finish time or distance. Enter the other two values. Splits assume a constant pace and include the final partial segment. Share a plan as text, an image or a link. The references provide context and limitations. They do not validate this page’s illustrative multipliers, lookup values or predictions.
What is a complete worked example for Calculate = Pace; Distance = 10?
Inputs: Calculate = Pace; Distance = 10; Distance unit = Kilometres; Time — hours = 0 h; Time — minutes = 50 min; Time — seconds = 0 s; Pace — minutes = 5 min; Pace — seconds = 0 s; Pace unit = Kilometres; Split unit = Kilometres. Calculation: p = t / D; t = D × p; D = t / p; 1 mi = 1.609344 km. Results: Pace per kilometre = 5:00 min/km; Pace per mile = 8:03 min/mi; Finish time = 0:50:00; Distance (km) = 10.000 km; Distance (mi) = 6.214 mi; Total time = 50.00 min; Average speed = 12.00 km/h; Average speed = 7.46 mph.