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Quick answer
What does the Race time predictor calculate?
What rough finish time follows from a recent race and target distance? This calculator uses recent race distance, recent race time, target race distance, and fatigue exponent to estimate distance-based finish estimate immediately in your browser.
With the values currently entered, the result is 52m 7s — projected finish time. It also shows projected pace, and distance ratio.
How to use the Race time predictor
- Replace the example values with your own numbers.
- Review the result and supporting figures as they update automatically.
- Check the formula and assumptions before using the estimate for a decision.
Inputs used
- Recent race distance — entered in km
- Recent race time — entered in minutes
- Target race distance — entered in km
- Fatigue exponent — entered in ×
Race time predictor formula
Recent time × (target distance ÷ recent distance)^fatigue exponent
Assumptions
- Training and conditions are comparable.
- This is a performance projection, not a health recommendation.
Practical guide
Race time predictor example and edge cases
What rough finish time follows from a recent race and target distance? Let's use a concrete example, then look at the assumptions that can move the answer.
Example: A practical race time predictor scenario
For this example, use recent race distance of 5 km, recent race time of 25 minutes, target race distance of 10 km, and fatigue exponent of 1.06 ×. These are starting values, so replace them with numbers that match your situation.
- Recent race distance
- 5 km
- Recent race time
- 25 minutes
- Target race distance
- 10 km
- Fatigue exponent
- 1.06 ×
Calculated result52m 7sprojected finish time
Start with projected finish time. Then check projected pace, and distance ratio to understand what sits behind the main result.
Example results use the default display profile. The calculator above follows your selected country and units.
How to read the result
- Read the main result first. The supporting figures for projected pace, and distance ratio explain how the estimate is built.
- The method is Recent time × (target distance ÷ recent distance)^fatigue exponent. Keep the units consistent and use values from the same time period.
Edge cases worth checking
When recent race distance is unusual
Training and conditions are comparable. Double-check this input before relying on the result.
When fatigue exponent is uncertain
This is a performance projection, not a health recommendation. Run a lower and higher value to see a useful range.
What changes the result most
Recent race distance
Measure recent race distance with the same unit shown beside the input. Convert first if your source uses another unit.
Recent race time
Keep recent race time on the same time basis as the other inputs. Monthly and annual values are easy to mix up.
Target race distance
Measure target race distance with the same unit shown beside the input. Convert first if your source uses another unit.
Try a different scenario
Small changes show whether the answer is stable or sensitive.
Recent race distance: 10% lower
5 km52m 7sprojected finish time
Recent race distance: 10% higher
6 km42m 58sprojected finish time
Recent race time: 10% higher
28 minutes58m 23sprojected finish time
Common mistakes
Check recent race distance
Training and conditions are comparable. Make sure this matches the number you enter.
Keep fatigue exponent consistent
This is a performance projection, not a health recommendation. Use the same units and time period throughout the calculation.
Do not rely on one race time predictor scenario
Run a cautious case and an optimistic case. The range is often more useful than one exact-looking number.
Use this result well
What rough finish time follows from a recent race and target distance?
Use it for activity planning, not medical diagnosis or individualized health advice.