Calculate running pace, speed and predicted race times for 5K, 10K, half-marathon and marathon.
A running pace calculator finds your average pace per kilometre (or per mile), and predicts your finish time for any race distance based on a known time at another distance. The Pete Riegel formula has been the gold standard for race time prediction since 1977 and is used by runners worldwide.
Knowing your pace lets you train deliberately at specific intensities — easy runs at 60% of 5K pace, threshold runs at 88%, and intervals at 95%+. Race day pacing is then a matter of executing the right effort, not just running as hard as possible from the start.
T_2 = T_1 \times \left(\frac{D_2}{D_1}\right)^{1.06}
Inputs: You ran a 5 km race in 24:00. Predict your marathon time.
Riegel's formula assumes you have done equivalent training for both distances. Most runners who try to predict a marathon time from a 5K result have done plenty of 5K work but not enough long runs. Reality is usually 10–20 minutes slower than the prediction unless you have logged 4–6 months of 50+ km weekly mileage.
For a new runner, the right pace is one you can sustain for 30–60 minutes while maintaining a conversation. This is typically 6:30–8:00 per km for most adults. Forget your watch in the first 6 weeks — build the habit of running consistently before worrying about speed.
EMI Calculator Mortgage Calculator SIP Calculator Compound Interest GST / VAT Calculator Salary Calculator Unit Converter Currency Converter Scientific Calculator Concrete Calculator Paint Calculator Tile Calculator Calorie / TDEE Body Fat Macro Calculator O-Ring Sizes Bolt & Nut Sizes Pipe Sizes Wire Gauge AWG Needle Gauge Chart IV Cannula Sizes Suture Sizes Catheter French Sizes Drug Dosage See all 90+ calculators ›