Running Pace Calculator
Calculate pace, finish time or distance — and predict your race times from your 5K performance.
Race Time Predictor
Enter your recent 5K time to predict your 10K, half marathon and marathon finish times.
Predictions use Riegel's formula: T2 = T1 × (D2/D1)^1.06. Actual race performance depends on training, conditions and race strategy.
Pace zones
| Zone | Pace (min/km) | Feel | Purpose |
|---|---|---|---|
| Easy | 6:30 – 8:00+ | Comfortable, can hold conversation | Recovery, long slow runs, base building |
| Moderate | 5:30 – 6:30 | Slightly breathless, full sentences | Aerobic base, steady-state cardio |
| Tempo | 4:45 – 5:30 | Comfortably hard, short sentences | Lactate threshold improvement |
| Threshold | 4:15 – 4:45 | Hard, 2–3 word phrases only | Race pace for 10K, half marathon |
| Speed | <4:15 | Very hard, unsustainable for long | 5K race pace, intervals |
Frequently asked questions
What is a good 5K time for beginners?
For a first-time runner, completing a 5K in any time is an achievement. A typical beginner running time is 35–45 minutes (7–9 min/km). After 3–6 months of regular training, many beginners reach 28–35 minutes. A "good" recreational runner time is under 30 minutes for men, under 35 minutes for women.
How do I convert my treadmill speed (km/h) to pace?
Pace (min/km) = 60 ÷ speed (km/h). Example: 10 km/h → 60÷10 = 6:00 min/km. At 8 km/h, pace = 60÷8 = 7:30 min/km. Use the Treadmill Pace Converter tool on this site for quick conversions.
What is the difference between pace and speed?
Pace is time per unit distance (e.g. 6 min/km), while speed is distance per unit time (e.g. 10 km/h). Runners typically use pace; cyclists and triathletes often use speed. They are inversely related: faster pace = higher speed.
How long does it take to train for a half marathon?
Most beginner half marathon training plans are 12–16 weeks, assuming you can already run 5K comfortably. You will gradually build your long run each week, reaching 18–20 km in training before tapering for race day. Three to four runs per week is typical.
Is the race time predictor accurate?
The predictor uses Riegel's formula which is accurate for well-trained runners at similar effort levels. For beginners, marathon predictions tend to be optimistic — beginners fade more in the second half due to lower glycogen stores and less training. Use it as a guide, not a guarantee.