Split, watts and calories converter

The formulas

These are the formulas Concept2 publishes for its monitors. Pace here means seconds per metre, so a 2:00 split is 120 ÷ 500 = 0.24.

• Watts = 2.80 ÷ pace³
• Calories per hour = (4 × watts ÷ 1.1639) + 300

Worked example: 0.24 cubed is 0.013824, and 2.80 ÷ 0.013824 is about 203 watts. Then 4 × 203 ÷ 1.1639 is about 696, and adding the base of 300 gives about 996 calories an hour.

How to use it

Watts give you a fairer way to compare efforts than split, because they show how much harder each second gets. Set a consistentdrag factor so results stay comparable, then use the pace calculator to set training zones. To turn a split into a calorie total for a session, use the calorie estimator. If you’re aiming at a 2k, read our2k pacing strategy.

Frequently asked questions

How do you convert a rowing split to watts?

Concept2 gives the formula as watts = 2.80 / pace cubed, where pace is seconds per metre. A 2:00 /500m split is 0.24 seconds per metre, which works out at about 203 watts.

Why does a small drop in split need so many more watts?

Watts rise with the cube of speed. Going from 2:00 to 1:50 /500m takes you from about 203 to 263 watts, so about 9% more speed needs about 30% more power.

What does calories per hour mean on a Concept2 monitor?

It is the rate you would burn calories at if you held that pace for an hour, using the monitor’s standard figure. It includes a base of 300 calories an hour.

Does this work on machines other than a Concept2?

The sums are Concept2’s, so only a Concept2 will match them exactly. Monitors on other machines may use their own formulas.