Running Pace Calculator

About this tool

The Running Pace Calculator solves for pace, finish time, or distance when the other two values are known. Pick the Pace, Time or Distance tab, enter the two values it asks for, and the answer appears instantly. A km/mi toggle sets the unit for distance and pace, and pace results are also shown in min/km. Times are entered as h:mm:ss (or mm:ss) and paces as min:ss. Whenever a pace is known, the tool also lists finish times at that same even pace for 1 km, 1 mile, 5K, 10K, 15K, the half marathon (21.0975 km) and the marathon (42.195 km). These are straight pace × distance figures, not fatigue-adjusted predictions — most runners slow down over longer races, so treat the marathon figure as an even-pace target rather than a forecast.

Why use it

• Solves for pace, time, or distance from the other two values.

• Lists finish times at your pace for 1 km, 1 mile, 5K, 10K, 15K, half marathon and marathon.

• Supports both kilometres and miles with a single toggle.

• Accepts natural time formats such as 25:00 or 1:45:30.

• Replaces the manual long division most runners do mid-run when checking pace at split markers.

• Privacy-first: your race times and target paces are never sent to any server.

How to use

1. Choose a tab: Pace (from distance and time), Time (from distance and pace) or Distance (from time and pace).
2. Select km or mi to set the unit for distance and pace.
3. Enter the two values the tab asks for — times as h:mm:ss or mm:ss, paces as min:ss.
4. Read the result, which updates as you type; pace is also shown in min/km.
5. Check the race finish times listed below for 1 km up to the marathon at that same pace.
6. Switch tabs to work backwards, for example from a goal finish time to the pace you need.

When it helps

• Planning training runs at a target pace.
• Working out the pace needed for a goal finish time at a given distance.
• Calculating whether a target race time is achievable at a given pace.
• Checking how far you covered from a run's time and average pace.
• Tapering before a goal race and verifying that the chosen target pace matches your fitness.
• Converting a per-mile pace from a US training plan into min/km.

Examples

Tips

• Run your easy days 30-60 seconds per mile slower than goal race pace — most age-group runners run their easy days too fast.
• Treat the half and marathon times as even-pace targets; real race times over long distances are usually slower than a shorter race's pace suggests.
• Build pace memory by running the first kilometer of every workout at exact target pace for the day — this trains pacing intuition.
• Adjust target pace upward by 1-2% per 10°C above 20°C — heat dramatically reduces sustainable pace, especially after the 60-minute mark.
• Check splits every 1-2 km in a race rather than every km — this prevents over-correcting on a single slow split caused by elevation or wind.
• If your goal is a sub-marathon time, generate a training plan using McMillan or Daniels VDOT, not just race-pace splits — easy/threshold/interval paces all matter.

Frequently Asked Questions

Glossary

Pace

Time per unit distance; expressed as min:sec/km or min:sec/mile. A 5:00/km pace means each kilometer takes 5 minutes.

Speed

Distance per unit time; expressed as km/h or mph. The reciprocal of pace.

Riegel formula

T2 = T1 × (D2/D1)^1.06. Predicts time over a new distance from a reference race time at another distance.

VDOT

Jack Daniels' performance metric that combines VO₂ max and running economy; a more accurate cross-distance predictor than Riegel.

Negative split

Running the second half of a race faster than the first. Optimal pacing strategy for most distances.

Marathon (42.195 km)

Standardized long-distance race of 26.2 miles or 42.195 km, originating from the 1908 London Olympics.

Threshold pace

Pace sustainable for ~60 minutes; corresponds to lactate threshold and roughly 15K race pace for trained runners.