Pace Calculator
Calculate your pace for any distance
Pace — or tempo — is the time it takes you to cover one kilometre (or mile). It is the single most important metric for any runner: it defines the intensity of your workout, helps you plan a race, and allows comparison of effort across different distances. With this free calculator, enter distance and time (or target pace) and receive splits per km, predictions for other distances, and a pacing plan for race day.
How to use the calculator
- 1
Choose the distance
Select a common distance (5K, 10K, half marathon, marathon) or enter a custom distance in kilometres. The calculator works for any value between 0.1 km and 100 km.
- 2
Enter time or pace
Enter total time (for example 50 minutes for 10 km) and the calculator returns pace per km. Or enter a target pace (for example 5:00/km) and see the predicted time for the distance.
- 3
Review the results
See splits km by km, predictions for other distances using the Riegel formula, and effort-zone recommendations (easy, tempo, VO2 max) based on your current pace.
- 4
Plan race day
The Race Day Planner shows how to pace your race: even, negative split or progressive. Pick the strategy and receive target times per kilometre so you do not start too fast.
Pace basics
What is pace?
Pace is the time per kilometre (or per mile in the US and UK). A pace of 5:00/km means you take 5 minutes to cover 1 km. Hold that pace for 10 km and you finish in 50 minutes. It is runners' favourite metric because it is directly comparable across workouts, regardless of speed in km/h.
Pace vs speed
Speed in km/h and pace in min/km express the same thing. 12 km/h = 5:00/km. 10 km/h = 6:00/km. Most runners prefer pace because the numbers are more intuitive: "I can hold 5:30/km for 10 km" is more concrete than "I can hold 10.9 km/h".
Average vs instantaneous pace
Average pace is the mean of the whole workout; instantaneous pace (shown on the GPS watch) varies second by second. Instantaneous pace is noisy — hills, traffic stops, weak GPS signal — so do not obsess over it. Use the average pace per km (split) as your reference.
The Riegel formula for predictions
The formula T2 = T1 × (D2/D1)^1.06 predicts your time at a distance (D2) from a known time at another distance (D1). The 1.06 exponent reflects the fact that running longer is disproportionately harder. It is an optimistic prediction that assumes you have trained adequately for the target distance.
Training pace zones
A balanced training plan combines runs at different intensities. Use your 5K or 10K pace as a reference and calculate the following zones:
Easy / Recovery
5K pace + 60 to 90 seconds per km. About 80% of your weekly kilometres should be run at this pace. You should be able to hold a normal conversation. Builds aerobic base without overload.
Long run
5K pace + 45 to 75 seconds per km. The longest run of the week, usually on the weekend. Progressively increase distance to improve aerobic endurance and fat-burning efficiency.
Tempo / Threshold
10K to half-marathon race pace. A "comfortably hard" pace — you could sustain it for about 1 hour. Improves lactate threshold. Typical sessions: 20-40 minutes continuous or in blocks.
Intervals (VO2 max)
3K to 5K race pace. Short repeats (400 m to 1 km) with recovery between each. Improves maximal aerobic capacity. Typical sessions: 6×800 m @ 5K pace with 2 min jog recovery.
Speed / Sprint
Pace faster than 3K race pace. Very short repeats (100-400 m) with full recovery. Improves strength, power and running economy. Use sparingly — maximum 1× per week.
Frequently asked questions
How do I calculate my target pace for a race? +
Take a recent time from a shorter race and apply the Riegel formula (our calculator does this automatically). If you ran 10 km in 50 minutes, the prediction for half marathon is about 1h50m (pace 5:13/km). Train specifically for the target distance for at least 8-12 weeks before the race.
What is a good pace for beginners? +
If you are starting to run, do not worry about absolute pace — focus on running comfortably long enough. A pace between 7:00 and 8:30/km is typical for beginners and is absolutely acceptable. Progression comes naturally with weeks of consistent training. Focus on time on feet, not speed.
My pace varies a lot between workouts. Is that normal? +
Yes, completely normal. Pace depends on many factors: temperature, humidity, sleep, stress, terrain, wind, hydration and emotional state. Variations of 10-20 seconds per km between similar workouts are expected. Use Rate of Perceived Exertion (RPE 1-10) to complement pace — some days the body asks for slower, and that is okay.
Should I use pace per km or per mile? +
Use the unit that makes sense in your region. In Europe, Latin America and most of the world, min/km is the norm. In the US and UK, min/mi. To convert: 1 mile = 1.609 km, so pace 5:00/km ≈ 8:03/mi. The calculator accepts both.
How do I improve my pace over time? +
Three principles: consistency (run 3-5× per week regularly), controlled progression (increase volume or intensity by about 10% per week, not both at once) and variety (alternate easy, long run, tempo and intervals). With these three, pace improves naturally in 6-12 weeks. Create a free RunningWithAI account for an adaptive plan.
Should I pace a race evenly or as a negative split? +
The negative split (second half faster than the first) is the most effective strategy for most runners, because it lets you manage effort and push when you are already warmed up. For beginners, an even pace is easier to execute. Always avoid the positive split (starting too fast) — it is the most common recipe for a second-half collapse.
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