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Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →BHP means brake horsepower, HP means horsepower, and PS means metric horsepower. The numbers are close but not identical: mechanical horsepower is about 745.7–746 watts, while PS is 735.49875 watts. More importantly, a power figure’s measurement point and test standard can matter more than the abbreviation attached to it.
BHP means brake horsepower: power measured at an engine or motor’s output shaft using a brake or dynamometer-type test arrangement. HP is the broader abbreviation for horsepower, while PS means Pferdestärke, or metric horsepower.
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HP and PS are different units, although they are close in size. One mechanical horsepower is about 745.7–746 watts, while one PS is 735.49875 watts. That means 1 hp is approximately 1.014 PS, and 1 PS is approximately 0.986 hp.
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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsHowever, the unit is only part of the comparison. Before deciding which vehicle is more powerful, check where the power was measured, which test standard was used, and whether the figure describes peak engine power, motor power, system power, or power at the wheels.
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HP, BHP and PS at a glance
| Label | What it means | What to remember |
|---|---|---|
| HP | Horsepower; commonly mechanical horsepower in the United States | A unit of power, approximately 745.7–746 W |
| BHP | Brake horsepower | Describes horsepower measured at an engine or motor output shaft under a defined test arrangement |
| PS | Pferdestärke, German for “horse strength” | Metric horsepower, equal to 735.49875 W |
| kW | Kilowatt, an SI unit of power | Often the clearest unit for technical comparisons because it avoids the hp-versus-PS ambiguity |
In casual vehicle advertising, “HP” and “BHP” are sometimes used as though they mean the same thing. That does not establish a universal industry rule. The exact test procedure and measurement point determine what the number represents.
What does BHP mean?
BHP stands for brake horsepower. It is power measured at the output shaft of an engine or motor. In a traditional test, a brake or dynamometer resists the shaft while measuring torque and rotational speed. The word “brake” refers to the test device that absorbs or controls the engine’s output; it does not mean the vehicle’s braking power.
BHP is therefore best understood as a measurement context, not as a completely different physical quantity from horsepower. Both describe power. “Brake” tells you that the measurement concerns output from the engine or motor shaft under a specified test arrangement.
That distinction matters because power can be reported in several ways, including:
- gross engine power, measured under a particular laboratory configuration;
- net or as-installed engine power;
- brake or shaft power;
- power measured at the vehicle’s wheels; and
- combined power from a hybrid system or multiple electric motors.
For example, SAE J1349 is intended to produce repeatable as-installed net engine power and torque ratings that represent typical customer-service performance rather than an unusually optimized laboratory setup. An engine figure produced under that type of standard is not automatically equivalent in context to an enthusiast’s chassis-dynamometer result.
What does HP mean?
HP is the general abbreviation for horsepower. In U.S. vehicle specifications, it commonly means mechanical horsepower:
1 mechanical hp ≈ 745.7–746 W = 0.7457–0.746 kW
But “HP” by itself does not always tell you everything you need to know. It may not identify the test standard, the measurement location, the correction method, or whether the manufacturer is using mechanical horsepower rather than metric horsepower.
That is why “300 hp” is not a complete technical description until you know whether it is an engine-rated figure, a wheel-horsepower result, a peak value, or a number produced under another defined convention.
What does PS mean?
PS means Pferdestärke, or metric horsepower. It is a power unit equal to:
1 PS = 735.49875 W ≈ 0.7355 kW
PS is slightly smaller than mechanical horsepower. As a result, the same physical power produces a slightly larger numerical value when expressed in PS:
- 100 hp ≈ 101.4 PS
- 100 PS ≈ 98.6 hp
- 150 hp ≈ 152.1 PS
- 150 PS ≈ 147.9 hp
- 200 hp ≈ 202.8 PS
- 200 PS ≈ 197.2 hp
A car does not become more powerful because its specification changes from HP to PS. The difference is primarily a unit conversion. Acceleration and overall performance also depend on vehicle mass, gearing, traction, aerodynamics, torque delivery and test conditions.
HP versus PS: conversion table
| Mechanical horsepower | Approximate PS | Approximate kW |
|---|---|---|
| 100 hp | 101.4 PS | 74.6 kW |
| 150 hp | 152.1 PS | 111.9 kW |
| 200 hp | 202.8 PS | 149.1 kW |
| 250 hp | 253.5 PS | 186.4 kW |
| 300 hp | 304.2 PS | 223.7 kW |
For quick calculations, use these rounded formulas:
PS = mechanical hp × 1.014mechanical hp = PS × 0.986kW = mechanical hp × 0.7457kW = PS × 0.7355mechanical hp = kW × 1.341PS = kW × 1.360
These are suitable for consumer comparisons. Avoid displaying unnecessary decimal places: a manufacturer’s rounded 200-hp rating does not become more accurate simply because a calculator returns several digits.
Why kW is often the fairest comparison
The watt and kilowatt are SI units, so kW avoids the question of whether a specification uses mechanical horsepower or metric horsepower. The following figures are rounded to the nearest whole number:
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| Power | Approximate mechanical hp | Approximate PS |
|---|---|---|
| 50 kW | 67 hp | 68 PS |
| 75 kW | 101 hp | 102 PS |
| 100 kW | 134 hp | 136 PS |
| 150 kW | 201 hp | 204 PS |
| 200 kW | 268 hp | 272 PS |
For anyone who wants worked examples involving horsepower, torque, displacement and gearing, Auto Math Handbook by John Lawlor is a relevant automotive reference. It was published by HP Books and covers the calculations behind these specifications; verify the available edition and seller listing before buying.
Horsepower, torque and engine speed
Torque is twisting force. Horsepower is power—the rate at which work is done. They are related, but they are not interchangeable.
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For torque expressed in pound-feet and engine speed expressed in revolutions per minute, the customary U.S. formula is:
hp = torque (lb-ft) × rpm ÷ 5,252
This relationship explains why two engines with similar peak horsepower can feel very different. One may produce substantial torque at low rpm, making it responsive in everyday driving. Another may produce its peak power at a much higher rpm and require more engine speed—or different gearing—to deliver its best acceleration.
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- the torque curve and the rpm at which torque peaks;
- the rpm at which horsepower peaks;
- transmission ratios and final-drive gearing;
- vehicle weight and payload;
- traction and tire performance; and
- how long the engine or motor can sustain its rated output.
Why engine horsepower and dyno horsepower differ
A manufacturer may quote power at the engine, while a chassis dynamometer measures power after it has passed through the transmission, driveshafts, differential and other parts of the drivetrain. The latter is commonly described as wheel horsepower.
Because the measurement points are different, a wheel-horsepower result is not automatically comparable with an engine-rated BHP or HP figure. SAE research distinguishes inertia-dyno horsepower, OEM-rated net horsepower and power delivered to the ground.
There is no single drivetrain-loss percentage that can be applied reliably to every vehicle. Results can vary with:
- the dyno’s design and calibration;
- the correction standard used;
- ambient temperature and air pressure;
- fuel and engine calibration;
- tire condition and inflation;
- the selected gear and test procedure; and
- the exact point at which power is measured.
When comparing a brochure number with a dyno chart, first identify the measurement point and test method. A lower wheel figure does not necessarily contradict a higher engine rating; it may simply describe power after the drivetrain rather than at the engine shaft.
How electric and hybrid vehicles complicate the labels
Electric motors also produce measurable mechanical power, but an EV specification may refer to one motor, combined motor output, rated system power, maximum wheel power, or a battery-and-inverter-limited value. Applying “BHP” to every EV can hide those distinctions.
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Hybrid vehicles add another potential complication because the gasoline engine and electric motor may reach their maximum outputs at different times. A quoted combined system figure is not always the simple arithmetic sum of the two peak ratings.
SAE J2908 addresses vehicle power and rated system power for electrified powertrains, including methods related to maximum wheel power and system-level ratings. For technical comparisons, look for the exact definition of the quoted figure rather than assuming that a motor rating, system rating and wheel result are equivalent.
How to compare two horsepower figures correctly
- Identify the unit. Is the number in mechanical hp, PS or kW? Convert the figures to a common unit before comparing them.
- Identify the measurement point. Is it measured at the engine or motor shaft, at the wheels, or at the complete hybrid system?
- Check the test standard. Look for a defined standard such as an as-installed net-power procedure, and note whether the figure is manufacturer-rated or dyno-measured.
- Check whether it is peak power. A peak value does not show the complete torque and power curves.
- Consider torque and rpm. The rpm at which power and torque peak affects how the vehicle responds in normal driving.
- Account for the vehicle, not just the engine. Weight, gearing, traction, aerodynamics and tires all affect acceleration.
- Compare like with like. Engine-rated BHP should not be treated as directly equivalent to wheel horsepower, even if both numbers use “hp.”
For readers who need the technical documents behind engine and electrified-powertrain measurements, SAE’s engine power testing standards and automotive engineering references are the appropriate category of resource. Standards are technical documents rather than essential purchases for a basic HP-to-PS conversion, and the applicable edition and access terms should be checked directly with SAE International.
Common mistakes about BHP, HP and PS
“HP and PS are exactly the same.”
They are close but not identical. Mechanical horsepower is about 745.7–746 W; PS is 735.49875 W.
“BHP is always a separate, higher type of horsepower.”
BHP identifies a shaft-power measurement context. It is not a different form of energy, and the number still depends on the test procedure and measurement conditions.
“Every HP figure means BHP.”
Some vehicle advertising uses the labels loosely, but the abbreviation alone does not establish a universal measurement standard. Check the specification details.
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“Wheel horsepower is the same as engine horsepower.”
No. The drivetrain lies between the engine and the tires, and the two figures use different measurement reference points.
“The vehicle with the larger number is always faster.”
Only after converting the units and checking the measurement basis can the numbers be compared. Even then, acceleration depends on gearing, mass, traction, aerodynamics and the shape of the power curve.
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“More decimal places make the conversion more accurate.”
Not when the original specification has already been rounded or was measured under different conditions. Use sensible rounding for consumer comparisons.
Bottom line
BHP is horsepower measured at an engine or motor output shaft; HP is the general horsepower unit; PS is metric horsepower. One mechanical horsepower is approximately 1.014 PS, so the unit difference is small. In real vehicle comparisons, the measurement location and test standard can matter more than whether the label says HP, BHP or PS.
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Frequently Asked Questions
What does BHP stand for?
BHP means brake horsepower: power measured at an engine or motor output shaft using a defined brake or dynamometer-type test arrangement. It describes the measurement context rather than a fundamentally different kind of power.
Are HP and PS the same?
No. Mechanical horsepower is approximately 745.7–746 watts, while one PS is 735.49875 watts. Therefore, 100 hp is about 101.4 PS, and 100 PS is about 98.6 hp.
Is BHP the same as wheel horsepower?
Not necessarily. Engine-rated horsepower is measured at or attributed to the engine or motor, while wheel horsepower is measured after drivetrain components at the wheels. The test standards and measurement points must match before the figures can be compared.
Why is kW useful for comparing power?
Use kW when possible because it is an SI unit and avoids ambiguity between mechanical horsepower and metric horsepower. For quick conversions, 1 kW is about 1.341 hp or 1.360 PS.
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BHP is a shaft-measurement description, HP is the general horsepower unit, and PS is metric horsepower. Convert the units first, then compare the measurement point, test standard, torque curve, gearing and vehicle weight. An engine-rated figure and a wheel-dyno result are not automatically equivalent.
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