Cycling Calories Calculator

An arithmetic coincidence. One kilocalorie is 4.184 kJ, and human gross cycling efficiency is about 23.9 per cent, which is 1 divided by 4.184. Dividing your work by 4.184 and then by 0.239 returns almost the original number, so a power meter's kJ reading can be treated as kcal — typically within half a per cent.

Substantially, and it is a different kind of measurement. A MET table asks what activity you performed and looks up a population average. A power meter measures the work you actually did. For the anchor ride here, the MET route returns about 39 per cent more than the measured figure.

The share of metabolic energy that becomes useful work at the pedals. Trained cyclists measure roughly 20 to 25 per cent; the rest is lost as heat, which is why indoor riding without a fan is so punishing. It varies remarkably little with fitness and behaves almost like a constant.

Generally not, and doing so is the most common reason riders fail to lose weight despite high training volume. The figure here is gross cost, which includes the resting energy you would have spent anyway. Fuel the work you are about to do rather than repaying the work you have done.

For efforts beyond about 90 minutes, 30 to 60 g per hour, rising toward 90 g per hour with a glucose-fructose mix if your gut is trained for it. You cannot and need not replace the full energy cost during the ride — the aim is to protect glycogen, not to balance the ledger.

Most head units apply exactly this calculation but may assume a different efficiency, or use normalised rather than average power. Small differences in either input move the result by a few per cent. If yours reports calories close to your kJ figure, it is using an efficiency near 24 per cent.

For sustained efforts of around an hour, roughly 2.5 to 3.0 W/kg is typical of a fit recreational rider, 4.0 W/kg marks a strong amateur racer, and elite professionals exceed 5.5 W/kg. It is the number that predicts climbing performance, because gravity scales with mass.

Barely. Gross efficiency is close to a physiological constant, and training makes you faster mainly by raising the power you can sustain rather than by improving how efficiently you convert fuel into work. It does decline slightly with fatigue within a long ride.

For energy cost, average power is the correct input, because kilojoules are the integral of actual power over time. Normalised power is a weighting designed to reflect physiological stress, and using it here would overstate the work you actually performed.

Yes — this is gross expenditure. If you want the net cost of the ride specifically, subtract roughly one MET-hour per kilogram of bodyweight per hour, which for a 75 kg rider over 1.5 hours is about 113 kcal.

Good units claim 1 to 2 per cent accuracy, which is far better than any calorie estimate derived from heart rate or activity labels. Accuracy depends on regular zero-offset calibration and, for some designs, on temperature compensation.

Because roughly three-quarters of your metabolic energy becomes heat rather than work, and outdoors that heat is carried away by airflow. On a stationary trainer without a fan there is no convective cooling, so core temperature rises and sweat rate climbs at identical power output.

Yes. Smart trainers report power the same way, and the arithmetic is unchanged. Be aware that trainer power and outdoor power meter readings can differ by a few per cent, so compare like with like when tracking progress.

Use the MET Calories Calculator or the Calories Burned Calculator, which estimate from activity and duration. They are considerably less accurate — an activity label cannot distinguish a hard solo effort from sitting in a group at the same speed.

Not as units — 1 kcal is 4.184 kJ. The equivalence is specific to cycling and arises because human efficiency is near 24 per cent. It does not transfer to running or any other activity where work at a pedal is not being measured.

Because human cycling gross efficiency does not fall outside that range, and accepting a value that does would produce a confident, precise and entirely fictional calorie figure. The engine enforces the physiological domain rather than trusting the input.

Yes. It is free, requires no account, and has no usage limits. ApexConverter is funded by contextual advertising, never by selling user data.

No. The engine runs as Vanilla JavaScript inside your browser under our Zero-Server Client-Side Execution model. Your figures are computed locally and are never transmitted, logged, or stored.

It applies the standard closed-form formula in IEEE-754 double precision, rounding only at the display layer. The engine is reconciled against an independent reference implementation before release.

Yes. The interface is mobile-first with numeric keypad hints and is tested down to a 320-pixel viewport with no horizontal scrolling.