How to Calculate Running Pace From Distance and Time

Pace is the most useful number in running. It is also the one that trips up beginners the most because it lives in mixed units: minutes and seconds per mile, or per kilometer. This guide walks through the math from scratch, three real examples, and a shortcut for when you just want the answer in two seconds.

If you would rather skip straight to the result, free pace calculator does this in your browser — type a distance and a time, get pace, speed, and predicted race finishes. But if you want to actually understand it, keep reading.

The Pace Formula

Pace is just time divided by distance. The trick is keeping the units consistent and converting the result back into minutes and seconds, which is how runners read it.

The standard equation: Pace = Total Time (in seconds) ÷ Distance. Then you convert the seconds-per-mile result back into a minutes:seconds format.

Example: 5 kilometers in 25 minutes. That is 1500 seconds ÷ 5 km = 300 seconds per km, which is 5:00/km. Convert to miles by multiplying by 1.609 — about 8:03/mile.

That is the whole math. Two divisions, one unit conversion if you want to switch between metric and imperial.

Example 1: A 25-Minute 5K

You ran 5 km (3.107 miles) in 25 minutes flat. Total time in seconds = 1500.

• Pace per km = 1500 ÷ 5 = 300 seconds = 5:00/km
• Pace per mile = 1500 ÷ 3.107 ≈ 482.8 seconds ≈ 8:03/mile
• Speed = 60 ÷ 8.05 ≈ 7.45 mph or 12.0 kph

That is a respectable beginner-to-intermediate pace. Hold it for a half marathon and you finish around 1:45. Hold it for a full marathon and you finish around 3:31 — but you probably will not, because pace drifts on long efforts. Predictions assume perfect consistency.

Example 2: 10 Miles in 1 Hour 18 Minutes

10 miles in 1:18:00 is 4680 seconds. Pace per mile = 4680 ÷ 10 = 468 seconds = 7:48/mile. Speed ≈ 7.69 mph.

If you can hold this pace for 10 miles, your projected half marathon time is around 1:42:14 (at the same pace, no fade). Realistic half marathon times are usually a touch slower because you push past the distance you have practiced. Add 30-60 seconds per mile for races longer than your training peak.

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Example 3: A Marathon at 9:00/mile

You want to know how long a marathon takes at exactly 9:00/mile pace. The marathon is 26.219 miles. 9 minutes × 26.219 = 235.97 minutes = 3 hours 55 minutes 58 seconds.

Round-number takeaway: 9:00/mile is the sub-4 marathon pace with a tiny buffer. Drop to 9:09/mile and you finish at exactly 4:00:00 — no margin for slowdown, bathroom stops, or a tough mile 22.

This is why marathoners obsess over pace bands. Going out 10 seconds per mile too fast costs more than 10 × 26 = 260 seconds — it usually causes the wheels to fall off in the back half, which costs minutes, not seconds.

Pace vs Speed — Same Idea, Different Units

Speed and pace are mirror images. Speed says "how far per hour." Pace says "how long per mile or km." The conversion is just inversion plus unit math:

• mph from min/mile: 60 ÷ pace_in_decimal_minutes. So 7:30/mile = 60 ÷ 7.5 = 8.0 mph.
• kph from min/km: 60 ÷ pace_in_decimal_minutes. So 5:00/km = 60 ÷ 5 = 12.0 kph.
• min/mile from mph: 60 ÷ mph. So 6.0 mph = 10:00/mile.

Treadmills usually display mph or kph. Race results usually display pace. Knowing the conversion lets you set the right speed on a treadmill to hit a goal pace.

The Two-Second Shortcut

Doing this on a calculator is fine for one example. For training, race planning, and treadmill use, you want a tool. our pace calculator takes distance, hours, minutes, seconds, and gives you back pace per mile, pace per km, speed in both units, and projected 5K/10K/half/marathon times.

It runs entirely in your browser. Nothing uploads. No account needed. Open it on your phone the morning of a race, type your goal time, get the pace you need to maintain. Done.

Frequently Asked Questions

Is pace the same as speed?

They measure the same thing differently. Speed is distance per unit time (mph). Pace is time per unit distance (min/mile). Lower pace = higher speed.

Why do runners use pace and not speed?

Pace makes race math simple. If your pace is 8:00/mile, a 5K (3.1 miles) takes about 24:50. Try doing that math from "7.5 mph" on the fly and you will see why pace wins.

Are predicted race times accurate?

They assume perfect pacing for the full distance, which never happens. Predictions are best for distances close to what you have trained for. Add 5-10% to predictions for races much longer than your training distance.