Convert brake horsepower and RPM into crank torque — lb·ft or N·m, with hp/kW unit toggles.
Convert brake horsepower and RPM into crank torque — dyno-sheet style.
Power & engine speed
Use the RPM where that power was measured for a meaningful torque figure.
Dyno cell · brake torque
Torque from power & RPM
Dyno estimate
Calculated torque
382
lb·ft · 382 lb·ft · 517.9 N·m
Power
400
hp · 298.3 kW
Engine speed
5500
RPM
Formula: Torque (lb·ft) from power × 5252 ÷ RPM
Crank torque from brake power. Wheel torque after the gearbox and axle is a different number.
Torque from horsepower and RPM
Torque (lb·ft) = HP × 5252 ÷ RPM — the same relationship dyno sheets use.
Peak torque and peak horsepower rarely share the same RPM; pick the speed that matches your power figure.
Toggle lb·ft / N·m and hp / kW to match OEM specs or a European dyno printout.
Horsepower alone does not tell you how hard the crank is twisting at a given engine speed. This free torque calculator solves the classic brake-power relationship so you can turn a dyno HP number (or a solid estimate) and an RPM into crank torque in pound-feet or newton-meters.
Enter power and the RPM where it was measured. The dyno-cell view shows the calculated torque with power and engine speed alongside so you can sanity-check a cam swap, turbo map, or gearing discussion without digging out a slide rule. Defaults of 400 hp at 5500 rpm land near 382 lb·ft — a familiar street-performance ballpark.
Remember this is flywheel torque from brake power, not wheel torque after the transmission and axle. Pair the result with the horsepower calculator for the reverse check, or with gear-ratio and RPM-at-speed tools when you care about tractive effort on the road.
Worked examples
Peak horsepower at 6,500 rpm does not mean peak torque lives there. Running the reverse formula at that RPM often shows less torque than the engine made 2,000 rpm earlier — which is why a truck can feel stronger off-idle than a high-strung sports car with the same peak HP.
Torque from horsepower and RPM
Power
RPM
Torque
400 hp
5,500
382 lb·ft
400 hp
5,252
400 lb·ft
450 hp
6,500
364 lb·ft
300 hp
4,000
394 lb·ft
lb·ft = HP × 5252 ÷ RPM. Use the RPM printed next to that power number on the dyno sheet, not an arbitrary redline.
How to use the torque calculator
Enter brake horsepower or kilowatts. Use crank/flywheel power from a dyno sheet or a trusted estimate — not a marketing “crank HP” guess if you care about accuracy.
Enter engine RPM. Use the RPM at which that power figure was measured (peak HP RPM for peak-power torque, or another point if you want torque at that speed).
Read torque in the dyno cell. Switch lb·ft / N·m as needed and compare with your gearing or horsepower calculator for the reverse check.
Torque calculator FAQ
Use Torque (lb·ft) = Horsepower × 5252 ÷ RPM. The 5252 constant comes from converting radians and horsepower definitions so power, torque, and engine speed stay consistent in imperial units.
Torque is twisting force at the crank; horsepower is torque × RPM. Many engines make max torque earlier in the rev range, then horsepower keeps climbing as RPM rises even while torque falls off.
North American dyno sheets and OEM catalogs usually quote lb·ft. European and SI specs use N·m. This calculator converts both (1 lb·ft ≈ 1.356 N·m) so you can match the unit on your dyno chart or parts listing.
Yes. Toggle to kW and enter brake power; the tool converts to horsepower internally (1 hp ≈ 0.746 kW), runs the torque formula, and can display the result in lb·ft or N·m.
This is crank (flywheel) torque from brake horsepower and RPM — the same relationship used on engine dyno sheets. Wheel torque after the transmission and axle is higher by the gear ratios and lower by drivetrain losses.
Torque (lb·ft) = 400 × 5252 ÷ 5500 ≈ 382 lb·ft. Enter the RPM where that power was measured. Peak-HP RPM and peak-torque RPM are usually different points on the same curve.