Running Pace Calculator
Calculate pace, time, or distance for any run. Get per-km splits, mile splits, and average speed in km/h or mph.
- Runs in your browser
- Private processing
- No uploads
01Why this pace tool
Pace, time, distance — one calculator.
Four reasons runners and coaches use this page to plan workouts, race targets, and easy days.
- 01
Pace, time, or distance — solve for any of the three
Fill in two values, the third appears. The same calculator answers 'how fast was that?', 'how long will this take?', and 'how far will I go?'.
- 02
Per-kilometer and per-mile splits
See how your pace scales across the run with a split table. Useful for race targets and progression-run planning.
- 03
Live as you type
Tweak any field and the other numbers move with it. Great for sanity-checking realistic goal times before race week.
- 04
Computed locally
Pace, distance, and times never leave your tab.
02How it works
Two values, the third.
- InputsDistance10kmTime52:30
Step 1Enter what you know
Two of: distance, time, pace. Type a target finish time, an average pace, or the distance you covered.
- Unitskmmi
Step 2Pick metric or imperial
Kilometers and minutes per kilometer, or miles and minutes per mile. Toggle without losing your inputs.
- Pace5:15min/kmPer-km splits ready
Step 3Read the result and splits
The third value appears alongside a split table. Use it to plan a race, pace a long run, or check what last week's effort actually translated to.
03Use cases
Where pace math shows up.
Race predictions, split tables, tempo planning — anywhere a target pace matters.
Predict a marathon finish time
Hit a half-marathon time you trust? Plug in the pace and a marathon distance to see a realistic finish prediction.
1:48 half → 3:47 marathon targetPlan race-day splits
Goal time of 1:30 over a half? Get the per-km splits you need to keep on pace — and how much margin a fast first mile gives away.
Half-marathon · 4:16/km splitsLong-run target pace
Easy-day pace shouldn't be marathon pace. Plug in your easy distance to confirm the average is actually 'easy'.
20 km long run · 5:40/kmSet a treadmill speed
Need to hold 4:30/km on a treadmill that's calibrated in km/h? Pace-to-speed conversion is built in.
Pace target → treadmill speedTempo workout planning
Build a tempo block: 3 × 2 km at your half-marathon pace. The calculator confirms the time each rep should land.
3 × 2 km · 4:40/km · 9:20 repsCoach-to-athlete handoff
Share the split table directly. Athletes train off paces; coaches design off times. Both views from one input.
Training block · paces table
04Quick tips
Plan paces realistically.
Four habits that keep predictions honest and race day calm.
- 01
Race times scale non-linearly
Marathon pace is rarely 2× half pace — fatigue cumulates. Use predictor tables alongside this tool for goal-setting at longer distances.
- 02
Hills and heat shift pace
Flat splits look ambitious on a hilly course. Adjust the goal pace upward for course profile before race day, not after the bonk.
- 03
Watch GPS drift
Watch-reported pace can wobble at the start of a run while it locks satellites. Use averages across mile/km markers, not the instant readout.
- 04
Train mostly slower than goal pace
Most aerobic work happens at easy pace, not goal pace. The split table helps you set easy targets too, not just race ones.
05Loved by
Marathoners, triathletes, and coaches.
Plug in goal time, get the per-km splits, tape them to my wrist. Race plan in 30 seconds.
Use it for swim-bike-run pacing. Distance and time in, average pace out, dial in the brick day.
Building training plans for athletes. The split table is what I copy into their weekly sheet.
06Questions
Pace math, plainly answered.
Questions before your first split table. Missing one? hello@wirelogs.com.
01Can I use this for any sport, not just running?
Yes. Pace = time / distance for any continuous-effort sport. Cycling, swimming, rowing — all work the same way, just in different units.
02How accurate is a predicted marathon time from a half?
Loosely. Most predictors assume similar training and a flat course. Reasonable rule: marathon time ≈ half-marathon × 2.10–2.15 for an experienced runner with proper buildup.
03Why are my per-km splits different from my watch?
Watches average over GPS samples, which drift slightly. The tool's splits are perfectly linear from your average. Real splits will vary with terrain and effort.
04Does the tool understand seconds vs minutes?
Yes. Time inputs accept hh:mm:ss; pace accepts mm:ss/km or /mile. Hit Tab between fields to move quickly.
05Is my data sent anywhere?
No. Pure arithmetic, locally.
06Is it free?
Yes. No sign-up, no usage cap, no watermark.
Ready when you are
Plan the splits.
Enter any two values above. The third appears alongside a complete split table.
- Pace · Time · Distancesolve any
- km · miboth units
- $0now and always