The pace, time and distance formulas
time = distance × pacepace = time ÷ distancedistance = time ÷ paceKeep units consistent. A pace of 5:00 per kilometre means 300 seconds per kilometre. Multiplying by 10 km gives 3,000 seconds, or 50:00.
Worked 10K example
Time: 50:00
Pace: 50 minutes ÷ 10 = 5:00 per km
Speed: 10 km ÷ 0.8333 hours = 12.0 km/h
Equivalent mile pace: approximately 8:03 per mile.
Common race distances
| Distance | Exact metric distance | At 5:00/km |
|---|---|---|
| 5K | 5 km | 25:00 |
| 10K | 10 km | 50:00 |
| Half marathon | 21.0975 km | 1:45:29 |
| Marathon | 42.195 km | 3:30:59 |
Keeping the standard half-marathon and marathon distances prevents small rounding errors from accumulating into visible finish-time differences.
How split tables work
A split table divides the total plan into checkpoints. Even splits are a neutral baseline: they make it easy to see whether the average pace is being maintained. They do not mean every kilometre must be identical. Hills, wind, turns, aid stations, surface and congestion can justify controlled variation.
Calculate pace, time, speed and kilometre or mile splits.
Converting min/km and min/mile
One mile is 1.609344 kilometres. To convert seconds per kilometre to seconds per mile, multiply by 1.609344. Do not multiply the displayed minutes and seconds as separate decimal numbers; convert the full pace to seconds first.
Equivalent-race estimates
T₂ = T₁ × (D₂ ÷ D₁)1.06The optional ToolBullet projection uses the widely known Riegel power-law form with an exponent of 1.06. It accounts mathematically for pace slowing as distance increases, but it cannot know whether the runner has trained for the longer event. Modern research continues to examine power-law and critical-power models, and individual athletes do not all share one fixed exponent.
| Deterministic calculation | Performance projection |
|---|---|
| 5:00/km over 10 km equals 50:00 if the average pace is maintained. | A 25-minute 5K projecting to another distance is an estimate based on a model. |
| Only arithmetic and unit conversion are involved. | Training, endurance, course and conditions can make the actual result faster or slower. |
Practical limitations
GPS distance and pace can fluctuate, particularly near buildings, trees and sharp turns. Pauses, course measurement, elevation, temperature, fuelling and fatigue affect recorded performance. Use a projection to set a provisional range, then compare it with recent longer training runs and race-specific preparation.
Using splits without forcing an even race
An even-pace split table is a planning reference, not a demand that every kilometre or mile be identical. Course elevation, wind, temperature, aid stations, congestion and tactical decisions can justify different segment targets. Compare chip time with chip time and gun time with gun time, and remember that GPS devices can measure a route slightly long or short. For a race projection, use a recent representative performance and treat the result as a range. A short-distance result does not prove that the endurance, fuelling and pacing required for a much longer distance are already in place.
How it works and sources
Model description and limitations reviewed 7 July 2026. ToolBullet uses these sources to explain the method and its limits; it does not replace coaching, medical advice or official governing-body records.