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Running Pace Calculator

Enter any two of distance, time, and pace to solve for the third, in kilometres or miles, with predicted finish times for 5K, 10K, half, and full marathon.

Solve for

Unit

Time

Hours, minutes, and seconds.

Everything is calculated in your browser. Nothing is uploaded.

Pace
5:00per km
Pace and speed
5:00
Pace /km
8:03
Pace /mi
12
Speed km/h
7.5
Speed mph
Race predictions
25:00
5K
50:00
10K
1:45:29
Half marathon
3:30:59
Marathon

Even-effort finish times at this pace. Most runners slow slightly over longer distances.

How to calculate running pace online

  1. Pick what to solve for

    Choose whether you want the pace, the finish time, or the distance, then set the unit to kilometres or miles.

  2. Enter the two values you know

    Type the distance, the time as hours, minutes, and seconds, or the pace as minutes and seconds per unit. The answer appears as you type, with no button to press.

  3. Read the result and splits

    See your pace in min per km and min per mile, your speed, and predicted finish times for 5K, 10K, half, and full marathon at that pace.

Why use this tool

Solve for any of the three

Give it any two of distance, time, and pace and it works out the missing one instantly. Switch the target without re-typing what you already entered.

Kilometres or miles

Enter distance and pace in km or mi with a single toggle. The result always shows pace in both min per km and min per mile so you never have to convert by hand.

Speed alongside pace

Every result includes your speed in km/h and mph next to the pace, so treadmill and cycling numbers line up with your run.

Race finish predictions

From your pace it projects even-effort finish times for the 5K, 10K, half marathon, and marathon distances, ready to compare against your goals.

Runs entirely in your browser

Everything is calculated on your device as you type. Nothing you enter is uploaded, stored, or logged.

About this tool

This running pace calculator ties together the three numbers every runner juggles: distance, time, and pace. Give it any two and it solves for the third. Enter a distance and a finish time to get your pace, a distance and a target pace to get your projected time, or a time and a pace to get how far you would go. The result updates the moment the inputs are valid, so you can nudge a number and watch the answer move.

Distance and pace can be entered in kilometres or miles with one toggle, and the result always reports pace both ways, in minutes per kilometre and minutes per mile, plus speed in km/h and mph. Standard race distances use their official lengths, so the half marathon is 21.0975 km and the marathon is 42.195 km, and the predicted finish times assume you hold an even effort across the whole distance. Real races drift a little from that, but it is the honest baseline for setting a goal pace or a split.

For converting a standalone measurement such as miles to kilometres, the unit converter is the direct tool, and for adding up interval or lap times the duration calculator handles the arithmetic. All of the maths here happens in your browser, so the times and distances you experiment with stay on your device.

Frequently asked questions

How does the pace calculator work?
It uses the relationship time equals distance times pace. Enter any two of the three and it rearranges the formula to solve for the missing one. Solving for pace divides your time by your distance, solving for time multiplies pace by distance, and solving for distance divides time by pace.
Can I use miles instead of kilometres?
Yes. The unit toggle switches both the distance field and the pace field between kilometres and miles. Whichever you pick, the result still shows pace in min per km and min per mile side by side, along with speed in km/h and mph.
How are the race finish times predicted?
They take your calculated pace and apply it evenly across each standard distance: 5 km, 10 km, the 21.0975 km half marathon, and the 42.195 km marathon. This assumes a constant effort, so treat the marathon and half figures as a target rather than a guarantee, since most runners slow slightly over longer distances.
What if I only know one value?
You need two of the three to solve the third. If you know only your distance, add either a time or a target pace. Until two valid values are present, the calculator waits and shows you which fields it still needs.
Is my data uploaded anywhere?
No. Everything runs in your browser; nothing is sent to a server. The distances, times, and paces you type are never uploaded, stored, or logged.

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