Enter distance and time or pace, to calculate the pace or time, respectively.

Distances can be entered as e.g. "5k", "1mi", "400yds", "Marathon", "Half Marathon", or simply "1000m" or "2.5km".

Time and pace can be entered as e.g. "30m", "7m30s", "4h30m", or (HH:)MM:SS.

Convert pace/speeds between minutes per kilometer, minutes per mile, kilometers per hour and miles per hour.

Convert distances between kilometres, miles, yards and furlongs.

By entering a known (recent) race time, you can predict the equivalent race time at another distance. This uses two different formulas, and shows both results as an interval:

• Peter Riegel's model from Runner's World in 1977. It is only recommended for races lasting between 3:30 minutes to 3:50 hours.
• David F. Cameron's model, based on top times at a variety of distances. Usually gives a more "pessimistic" prediction than Riegel's.

Distances can be entered as e.g. "5k", "1mi", "400yds", "Marathon", "Half Marathon", or simply "1000m" or "2.5km".

Time can be entered as e.g. "30m", "7m30s", "4h30m", or (HH:)MM:SS.

Enter distance and time to calculate split times. Select a pacing strategy, positive or negative splits.

Distances can be entered as e.g. "5k", "1mi", "400yds", "Marathon", "Half Marathon", or simply "1000m" or "2.5km".

Time can be entered as e.g. "30m", "7m30s", "4h30m", or (HH:)MM:SS.

This table shows paces multiplied by distances, which of course becomes finish times.

The laps in a backyard ultra are always 6706 meters (4.167 miles), and must be completed within one hour.

The table below shows what pace you must keep to be able to rest for a certain duration before the next lap starts.

This table shows the total distance completed after a certain number of laps. The time is the number of laps times 1 hour.

This calculator uses Jack Daniels' formula for calculating "VDOT" (V̇O₂max) from a race performance, which is not the same thing as VO₂max, but is somewhat related.

You can use VDOT to compare performances or to get training paces from (see Jack Daniels' calculator).

It is recommended to use a race distance between 1500 m and 50 km.

Distances can be entered as e.g. "5k", "1mi", "400yds", "Marathon", "Half Marathon", or simply "1000m" or "2.5km".

Time and pace can be entered as e.g. "30m", "7m30s", "4h30m", or (HH:)MM:SS.

This calculator "splits" the above distance into smaller chunks below, and calculates how fast each part of the distance was covered, on average. It is very likely that the speed varied, which means that some parts were even faster than this.

Distances can be entered as e.g. "5k", "1mi", "400yds", "Marathon", "Half Marathon", or simply "1000m" or "2.5km".

Time and pace can be entered as e.g. "30m", "7m30s", "4h30m", or (HH:)MM:SS.