Estimate gross oxygen cost from pace and uphill grade, explore time under explicit VO₂max/economy assumptions, or convert measured economy units. Optional body mass adds approximate gross calorie estimates.
Running Economy Formula
The following formula can be used to calculate running economy when you know the oxygen consumption (VO₂) at a steady pace:
Variables:
- RE is the running economy (ml/kg/km)
- VO₂ is the oxygen consumption at the running pace (ml/kg/min)
- T is the time spent running at that pace (minutes)
- D is the distance covered at that pace (kilometers)
Because speed v = D/T, this is equivalent to RE = VO₂ / v (with v in km/min). Individual economy requires steady-state oxygen measurement. Pace mode instead estimates gross VO₂ = 3.5 + 0.2S + 0.9S(G/100), with S in m/min and uphill grade G in percent; it cannot measure individual fitness. The usual running-equation range starts around 134 m/min. Downhill is excluded. Time mode assumes a user-supplied sustainable fraction of VO₂max and constant economy; it is not a validated race prediction. Unit-conversion mode uses 1 lb = 0.45359237 kg and 1 mi = 1.609344 km; 1 mL/lb/mi = 1/(0.45359237 × 1.609344) mL/kg/km. Approximate gross calories use 5 kcal/L oxygen. Fixed race-effort presets and universal fitness categories are not applied.
| Running economy | Speed | Calculated oxygen use | Interpretation at the same pace |
|---|---|---|---|
| 190 ml/kg/km | 0.20 km/min | 38.0 ml/kg/min | Lowest oxygen cost of these examples |
| 210 ml/kg/km | 0.20 km/min | 42.0 ml/kg/min | Middle oxygen cost |
| 230 ml/kg/km | 0.20 km/min | 46.0 ml/kg/min | Highest oxygen cost of these examples |
Economy comparisons are most meaningful when pace, grade, surface, and measurement method are held constant. At the same speed, a lower oxygen cost indicates better running economy.
What is Running Economy?
Running economy is a measure of efficiency, indicating how much oxygen a person consumes while running at a certain pace. It is often measured in milliliters of oxygen consumed per kilogram of body weight per kilometer (ml/kg/km). A lower value indicates better economy, meaning the runner can maintain a given speed while using less oxygen, which is advantageous for endurance performance.
How to Calculate Running Economy?
The following steps outline how to calculate Running Economy.
- First, determine the distance run (D) in kilometers.
- Next, determine the time taken to run the distance (T) in minutes.
- Next, measure VO₂ at that pace (ml/kg/min) or estimate it using a metabolic equation (often using speed and incline).
- Next, gather the formula from above: RE = (VO₂ × T) / D.
- Finally, calculate the Running Economy (RE) in ml/kg/km (lower values indicate better economy at that pace/grade).
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem:
Use the following variables as an example problem to test your knowledge.
Distance run (D) = 10 kilometers
Time taken to run the distance (T) = 50 minutes
Speed v = D/T = 0.2 km/min (12 km/h). On level ground (0% incline), an estimate is VO₂ ≈ 3.5 + 0.2 × 200 = 43.5 ml/kg/min (since 12 km/h = 200 m/min), so RE = (VO₂ × T) / D ≈ (43.5 × 50) / 10 = 217.5 ml/kg/km.
