What's the difference between pace and speed?

Pace is time-per-distance (e.g. 8:30 per mile), speed is distance-per-time (e.g. 7 mph). Runners usually think in pace; cyclists in speed.

Can I calculate race splits?

Yes — enter your target finish time and race distance, and the calculator shows your target pace plus 1-mile/km splits.

Does it account for altitude or heat?

No — pace calculations assume ideal conditions. For altitude adjustment, add roughly 2% per 1,000 ft above ~3,000 ft; heat cost is more variable.

What's a 'good' marathon pace?

Highly individual. 9:00/mile is typical for a mid-pack recreational runner. Sub-8:00/mile puts you around top 25%. Elite pace is under 5:00/mile.

How do I pace a long run versus a tempo run?

Long run: 60-90 seconds per mile slower than your race pace. The point is time on feet, not speed; faster long runs lead to overtraining. Tempo run: 'comfortably hard' pace, about 10-15 seconds per mile slower than 10K race pace, sustained for 20-40 minutes. Easy run: conversational pace, you should be able to speak in full sentences. Most amateur runners run their easy days too fast (defeating recovery) and their hard days too slow (defeating speed development) — the 80/20 rule (80% easy, 20% hard) corrects this.

How does treadmill pace compare to outdoor pace?

Treadmill at 1% incline approximately equals flat outdoor pace (compensates for lack of wind resistance and the belt assisting your stride). At 0% incline on a treadmill, you're effectively running 5-10 seconds per mile faster than the same effort outdoors. Hot/humid weather adds 15-30 seconds per mile to perceived effort outdoors. Wind: a 10mph headwind costs 5-10 seconds per mile; a tailwind helps about half that. Hills: each 100ft of elevation gain adds roughly 10-20 seconds per mile.

Health & Fitness · Free tool

Running Pace Calculator

Calculate pace, finish time, or distance for any run in km or miles. Perfect for 5K to marathon training, with free, instant results and no sign-up.

Updated June 2026

DistanceUnitHoursMinutesSeconds

Pace (per km)

5:00 /km

Pace (per mile)

8:03 /mi

Speed

12.00 km/h · 7.46 mph

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What it does

A free running pace calculator. Enter distance and finish time; get pace per kilometer, pace per mile, and speed in both km/h and mph. Works for training runs and race planning. Also calculates target pace from goal time, helps split-pace planning, and shows the speed conversion across units used by GPS watches and treadmills.

Knowing your pace is essential for structured training and pacing strategy on race day. Most amateur marathoners under-pace early and crash at mile 20; setting an accurate target pace and sticking to it (within 5-10 seconds per mile) is the difference between a PR and a bonk. Common race-pace anchors: 5K typically run at ~95% of VO2max effort, 10K at 85-90%, half-marathon at 80-85%, marathon at 70-78% of max heart rate. Pair with our running guide for beginner programs that use pace targets.

Pace varies by terrain, weather, and altitude. Trail runs add 1-3 minutes per mile vs. road. Heat above 70°F slows pace ~10-15 seconds per mile per 10°F increase. Wind: a 10mph headwind adds 5-8 seconds/mile, a tailwind helps about half that. Altitude above 3,000ft adds roughly 2% to pace per 1,000ft additional. For race-day strategy: run the first mile 10-15 seconds slower than goal pace (negative split is a proven marathon strategy), settle into goal pace through mile 18, then race the last 8.

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How to use it

Enter your distance (km or miles).
Enter your finish time (hours, minutes, seconds).
Read pace per km and per mile.
Check speed in km/h and mph for context.

When to use this tool

Race-day pacing strategy — knowing exact mile splits to hit a target time.
Training plan building — setting easy-day, tempo, and interval paces.
Treadmill workouts — converting outdoor pace targets to treadmill mph settings.
Comparing race performances across distances using pace per mile rather than total time.

When not to use it

Trail or ultra running — terrain variability makes pace less meaningful than effort or heart rate.
Cycling or swimming — those use power/wattage and pace per 100m respectively, not running-style pace.
Walking — calculator works mathematically, but walking has different physiological dynamics.

Common use cases

Marathoner targeting 4:00:00 finish needs 9:09/mile pace — calculator gives mile splits.
5K runner sees 25:00 finish equals 8:03/mile, plans tempo runs at slightly faster pace.
Comparing a 22:00 5K (7:05/mile) to a 50:00 10K (8:03/mile) shows 5K fitness ahead of 10K.
Trail runner converting flat-ground 8:00/mile to expected 10:00-11:00/mile on hilly trail.

Frequently asked questions

What's the difference between pace and speed?: Pace is time-per-distance (e.g. 8:30 per mile), speed is distance-per-time (e.g. 7 mph). Runners usually think in pace; cyclists in speed.
Can I calculate race splits?: Yes — enter your target finish time and race distance, and the calculator shows your target pace plus 1-mile/km splits.
Does it account for altitude or heat?: No — pace calculations assume ideal conditions. For altitude adjustment, add roughly 2% per 1,000 ft above ~3,000 ft; heat cost is more variable.
What's a 'good' marathon pace?: Highly individual. 9:00/mile is typical for a mid-pack recreational runner. Sub-8:00/mile puts you around top 25%. Elite pace is under 5:00/mile.
How do I pace a long run versus a tempo run?: Long run: 60-90 seconds per mile slower than your race pace. The point is time on feet, not speed; faster long runs lead to overtraining. Tempo run: 'comfortably hard' pace, about 10-15 seconds per mile slower than 10K race pace, sustained for 20-40 minutes. Easy run: conversational pace, you should be able to speak in full sentences. Most amateur runners run their easy days too fast (defeating recovery) and their hard days too slow (defeating speed development) — the 80/20 rule (80% easy, 20% hard) corrects this.
How does treadmill pace compare to outdoor pace?: Treadmill at 1% incline approximately equals flat outdoor pace (compensates for lack of wind resistance and the belt assisting your stride). At 0% incline on a treadmill, you're effectively running 5-10 seconds per mile faster than the same effort outdoors. Hot/humid weather adds 15-30 seconds per mile to perceived effort outdoors. Wind: a 10mph headwind costs 5-10 seconds per mile; a tailwind helps about half that. Hills: each 100ft of elevation gain adds roughly 10-20 seconds per mile.

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