Nm to HP Calculator

Q: How do I convert Nm to HP?

hp = Nm × rpm ÷ 7120.97. So 400 Nm at 2,000 rpm = 112.3 hp.

Q: How many horsepower is 500 Nm?

Unanswerable without rpm. 500 Nm is 105 hp at 1,500 rpm, 211 hp at 3,000 rpm and 421 hp at 6,000 rpm — all the same torque.

Q: What is the metric equivalent of the 5252 constant?

7120.97 for hp and 7023.55 for PS. Nm and hp are numerically equal at 7,121 rpm, exactly as lb-ft and hp are at 5,252.

Q: Why can't torque be converted to horsepower on its own?

Torque is force; power is the rate of doing work. A torque wrench held still applies torque and makes zero power. Speed is what turns one into the other.

Q: How do I convert Nm to kW?

Multiply Nm by rpm and divide by 9549.30 — that constant is simply 60,000 ÷ 2π.

Newton-meters become horsepower only once you know how fast the shaft is turning. Enter torque and rpm to get mechanical horsepower, PS and kilowatts together.

↓ Why rpm is required ↓ The 7121 constant ↓ Nm × rpm chart ↓ 500 Nm in hp ↓ FAQ

Torque & RPM to Horsepower

Torque (Nm)

Engine speed (rpm at that torque)

Mechanical horsepower

—

hp (bhp)

"500 Nm to hp" is one of the most-searched conversions in the automotive world, and it has no answer — not because the maths is hard, but because the question is missing half its inputs. Torque and power are different physical quantities, and the bridge between them is engine speed.

Quick answer: hp = Nm × rpm ÷ 7121. So 400 Nm at 2,000 rpm = 112 hp, and the same 400 Nm at 5,000 rpm = 281 hp. Same torque, two and a half times the power.

Why Torque Alone Cannot Become Horsepower

Put a torque wrench on a bolt and lean on it. You're applying torque. If the bolt doesn't turn, you're producing exactly zero power, no matter how hard you pull.

Torque is rotational force. Power is the rate of doing work. Work only happens when something moves, so power is torque multiplied by how fast the shaft is rotating. That's the whole reason an engine's power keeps climbing after its torque peak has passed: torque tapers gently while rpm keeps rising, and for a while the rpm term wins.

It also explains one of the most persistent confusions in car forums — a diesel with 500 Nm feeling less urgent than a gasoline with 350 Nm. The gasoline engine spins to 6,500 rpm and makes far more power. More on that in horsepower vs torque.

The Formula and Where 7121 Comes From

The constant looks arbitrary. It isn't — it is just unit bookkeeping.

Formulas

hp = (Nm × rpm) ÷ 7120.97

PS = (Nm × rpm) ÷ 7023.55 · kW = (Nm × rpm) ÷ 9549.30 · Nm = (hp × 7120.97) ÷ rpm
Derivation: P(W) = T × 2π × rpm ÷ 60, so kW divisor = 60000 ÷ 2π = 9549.30. Divide that by 1.34102209 hp per kW to get 7120.97.

Target unit	Divisor	Where it comes from
kW	9549.30	60,000 ÷ 2π — pure SI, no horsepower involved
hp / bhp	7120.97	9549.30 ÷ 1.34102209 (mechanical hp = 745.6999 W)
PS / KM / KS	7023.55	9549.30 ÷ 1.35962161 (metric hp = 735.4988 W)
hp from lb-ft	5252	33,000 ÷ 2π — the familiar imperial constant

The metric 5252: torque and power cross at 7121 rpm

Everyone knows horsepower and pound-feet meet at 5,252 rpm on a dyno graph. The metric equivalent gets almost no attention: newton-meters and mechanical horsepower are numerically equal at 7,121 rpm, and Nm meets PS at 7,024 rpm.

That isn't a physical event — it is an artefact of the units, the same way 5252 is. But it is a handy sanity check: if a spec sheet shows more hp than Nm, the engine is revving past 7,121 rpm at that point. See the 5252 rule for the full explanation.

Nm to HP at Common Engine Speeds

Mechanical horsepower for a given torque figure at a given rpm. Find your torque down the left, your rpm across the top.

Torque	1,500 rpm	2,000 rpm	3,000 rpm	4,000 rpm	5,000 rpm	6,000 rpm
100 Nm	21	28	42	56	70	84
150 Nm	32	42	63	84	105	126
200 Nm	42	56	84	112	140	169
250 Nm	53	70	105	140	176	211
300 Nm	63	84	126	169	211	253
350 Nm	74	98	147	197	246	295
400 Nm	84	112	169	225	281	337
450 Nm	95	126	190	253	316	379
500 Nm	105	140	211	281	351	421
600 Nm	126	169	253	337	421	506
700 Nm	147	197	295	393	492	590
800 Nm	169	225	337	449	562	674
1000 Nm	211	281	421	562	702	843

"How Many HP Is 500 Nm?" — The Honest Answer

This exact search runs thousands of times a month. Here's why no single number works:

500 Nm delivered at	Horsepower	PS	kW	Typical engine
1,400 rpm	98	100	73	Heavy truck diesel, low in the range
1,800 rpm	126	128	94	Large diesel at peak torque
2,500 rpm	176	178	131	3.0 diesel SUV
3,500 rpm	246	249	183	Gasoline turbo mid-range
5,000 rpm	351	356	262	Performance gasoline turbo
6,500 rpm	456	463	340	High-revving V8

Same 500 Nm. From 98 hp to 456 hp. If a spec sheet gives you torque without an rpm, it hasn't told you enough to work out power — and if a car listing quotes only torque, that's worth noticing.

Match the torque to its own rpm, not the power peak

A common mistake: taking peak torque (say 400 Nm at 2,000 rpm) and pairing it with peak power rpm (6,000) to "calculate" 337 hp. The engine never does that. By 6,000 rpm its torque has fallen to perhaps 260 Nm. Always use a torque figure with the rpm it actually belongs to.

Going the Other Way: HP to Nm

Rearranged, Nm = (hp × 7120.97) ÷ rpm. A 300 hp engine at 6,000 rpm is producing 356 Nm at that moment — which is usually well below its peak torque, because peak torque happens lower down. Use the HP to torque calculator for that direction, or kW to Nm if you're working in metric power.

For imperial torque see torque to HP (lb-ft), and to move between torque units use Nm to lb-ft. Metric power output is covered by Nm to kW, and the theory behind the whole relationship sits in the HP–RPM relationship.

How this calculator is checked

We derive this from first principles: power in watts = torque in newton-meters × angular velocity in radians per second, where ω = rpm × 2π ÷ 60. That gives an exact kW divisor of 60000 ÷ 2π = 9549.2966. Dividing by 1.34102209 hp per kW yields 7120.9718 for mechanical horsepower, and by 1.35962161 PS per kW yields 7023.5497 for metric horsepower. The calculator applies the unrounded constants; table values are rounded to whole horsepower. Engine descriptions in the 500 Nm table are illustrative of typical operating points, not specific vehicle claims.

Frequently Asked Questions

How do I convert Nm to HP?

hp = Nm × rpm ÷ 7120.97. So 400 Nm at 2,000 rpm = 112.3 hp.

How many horsepower is 500 Nm?

Unanswerable without rpm. 500 Nm is 105 hp at 1,500 rpm, 211 hp at 3,000 rpm and 421 hp at 6,000 rpm — all the same torque.

What is the metric equivalent of the 5252 constant?

7120.97 for hp and 7023.55 for PS. Nm and hp are numerically equal at 7,121 rpm, exactly as lb-ft and hp are at 5,252.

Why can't torque be converted to horsepower on its own?

Torque is force; power is the rate of doing work. A torque wrench held still applies torque and makes zero power. Speed is what turns one into the other.

How do I convert Nm to kW?

Multiply Nm by rpm and divide by 9549.30 — that constant is simply 60,000 ÷ 2π.

Is 400 Nm a lot of torque?

For a car, yes — typical of a modern 2.0 turbodiesel or mid-range gasoline turbo, usually arriving between 1,500 and 4,000 rpm.

Should I use peak torque or peak power rpm?

Whichever pair belongs together. Pairing peak torque with peak-power rpm invents a figure the engine never produces.

Does this formula work for electric motors?

Yes — identical physics. EV motors just hold near-peak torque from zero rpm, so power climbs almost linearly until the torque starts tapering.