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Power-to-Weight Ratio Calculator: hp/ton & W/kg

Calculate power-to-weight ratio for cars (hp/ton), cycling (W/kg with pro benchmark tiers), or general machinery (kW/kg). Instant results.

Calculation Mode

Use FTP (20-min test × 0.95) for a consistent benchmark

Power-to-Weight Ratio
3.57 W/kg
Performance tier: Trained / consistent rider

Cycling W/kg Benchmark Bands

Recreational: 1.5–2.5
Trained: 2.5–3.7
Competitive amateur: 3.7–4.2
Elite amateur: 4.2–4.7
Domestic pro: 4.7–5.5
WorldTour pro: 5.5–6.5+

Power-to-Weight Ratio = Power ÷ Weight. Automotive figures use hp per ton (2,000 lb) or hp per 1,000 lb. Cycling uses watts per kilogram of body weight (W/kg), the standard performance metric since it lets riders of different sizes be compared on climbs and efforts where power must move body mass against gravity. General/engineering mode normalizes any power and mass units to W/kg and kW/kg for comparing machinery, drivetrains, or vehicles regardless of scale.
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Reference Values

Last verified:
Category Range What It Means Status
Recreational cyclist 1.5–2.5 W/kg Casual or new rider without structured training. Most people who ride occasionally for fitness or commuting fall in this band. Poor
Trained / consistent rider 2.5–3.7 W/kg Regular structured training (club rides, consistent volume). This is the range most dedicated amateur cyclists reach within a season or two. Okay
Competitive amateur 3.7–4.2 W/kg Category racer able to hold their own in local road races and fast group rides. Good
Elite amateur 4.2–4.7 W/kg Top-tier amateur racer, often with a Cat 1/2 license or similar, capable of competing at regional elite level. Good
Domestic pro (men) ★ 4.7–5.5 W/kg Full-time domestic professional road racer — sustained climbing power at this level separates pros from strong amateurs. ★ Best
WorldTour pro (men) ★ 5.5–6.5+ W/kg Grand Tour general-classification contenders and top climbers sustain this for 20+ minutes on mountain stages. ★ Best
Pro women (elite) ★ 4.9–5.8 W/kg Top-level women's WorldTour racers — the men's/women's elite bands overlap because W/kg already normalizes for body size, but average power output differences still shift the absolute wattage. ★ Best
Automotive performance benchmark (hp/ton) 150–250 hp/ton Typical range for quick modern sport sedans and hot hatches. Below ~100 hp/ton feels sluggish; above 400 hp/ton (supercars, superbikes) produces sub-3-second 0-60 times. Good

Source: Cycling W/kg tiers aggregated from TrainerRoad power training guides and Roadman Cycling's W/kg performance benchmarks (FTP-based, 20-minute-plus sustained power). Automotive hp/ton benchmark is a general performance-car reference range, not a single official standard.

Worked Examples

Cycling — Competitive Amateur FTP Test

Mode
Cycling
Power
300 W (20-min FTP test)
Rider Weight
75 kg
4.00 W/kg — Competitive amateur

300 ÷ 75 = 4.00 W/kg, which sits in the 3.7–4.2 W/kg competitive amateur band — strong enough to be a factor in local road races.

Cycling — WorldTour Pro Climbing Power

Mode
Cycling
Power
420 W
Rider Weight
70 kg
6.00 W/kg — WorldTour pro

420 ÷ 70 = 6.00 W/kg, within the 5.5–6.5+ W/kg range sustained by Grand Tour climbers on mountain stages.

Automotive — Modern Sport Sedan

Mode
Automotive
Horsepower
400 hp
Weight
3,500 lb
228.6 hp/ton (114.3 hp per 1,000 lb)

Tons = 3,500 ÷ 2,000 = 1.75. hp/ton = 400 ÷ 1.75 = 228.6 hp/ton — solidly quick, comparable to a well-tuned performance sedan.

Automotive — Superbike vs. Car Comparison

Mode
Automotive
Horsepower
200 hp
Weight
420 lb
952.4 hp/ton

Tons = 420 ÷ 2,000 = 0.21. hp/ton = 200 ÷ 0.21 = 952.4 hp/ton — nearly 4x a fast sedan's ratio, which is why literbike motorcycles out-accelerate almost any car despite having far less raw horsepower.

General / Engineering — Industrial Electric Motor

Mode
General
Power
50 kW
Mass
400 kg
0.125 kW/kg (125 W/kg)

50,000 W ÷ 400 kg = 125 W/kg = 0.125 kW/kg — a useful figure for comparing motor or drivetrain density across designs regardless of absolute size.

How to Use This Calculator

  1. 1

    Choose a mode

    Select Cycling (W/kg), Automotive (hp/ton), or General/Engineering (kW/kg) depending on what you're calculating.

  2. 2

    Enter power output

    Horsepower for automotive, watts for cycling (use your FTP or a sustained effort), or kW/W for general machinery.

  3. 3

    Enter weight or mass

    Vehicle weight in lb for automotive, body weight in kg or lb for cycling, or mass in kg/lb for general mode.

  4. 4

    Read your ratio

    Updates instantly. Cycling mode also classifies your result into a performance tier from recreational through WorldTour pro.

What Each Value Means

hp/ton (hp per ton)
Horsepower divided by vehicle weight in tons (2,000 lb). The standard automotive-media shorthand for comparing acceleration potential across vehicles of different weight classes.
W/kg (watts per kilogram)
Power output in watts divided by body weight in kilograms. The standard cycling performance metric because it normalizes power for rider size, making climbing and acceleration ability comparable across different body weights.
kW/kg (kilowatts per kilogram)
Power in kilowatts divided by mass in kilograms. Used in general engineering and machinery design to compare power density across motors, engines, or vehicles regardless of absolute size.

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Frequently Asked Questions

What is a good power-to-weight ratio?
It depends entirely on the domain. In cycling, 3.7–4.2 W/kg is a competitive amateur racer, while WorldTour pros sustain 5.5–6.5+ W/kg on climbs. In cars, 150–250 hp/ton is a quick modern sport sedan, while supercars and superbikes exceed 400–900 hp/ton. There's no single universal 'good' number — always compare within the same category, since a motorcycle's ratio will always dwarf a car's.
How do you calculate power-to-weight ratio?
Divide power by weight: Power ÷ Weight. For cars, that's horsepower ÷ weight in tons (weight in lb ÷ 2,000) to get hp/ton. For cycling, it's watts ÷ body weight in kilograms to get W/kg. For general machinery, convert both to consistent units first (watts and kilograms) to get W/kg, or divide by 1,000 for kW/kg.
Why is W/kg used for cycling instead of raw watts?
Raw wattage rewards bigger riders who can produce more absolute power, but climbing and accelerating require moving your own body weight against gravity. W/kg normalizes for size, so a 60kg rider producing 240W (4.0 W/kg) and an 80kg rider producing 320W (also 4.0 W/kg) perform identically on a climb, even though their raw power numbers differ by 80 watts. This is why W/kg, not FTP in watts alone, is the standard way competitive cyclists compare climbing ability.
Why does a lighter car with less horsepower sometimes accelerate faster?
Acceleration depends on how much mass each unit of power has to move, not on horsepower alone. A 300 hp car weighing 2,800 lb (214 hp/ton) will out-accelerate a 400 hp car weighing 4,800 lb (167 hp/ton), because the lighter car has a better power-to-weight ratio despite having 100 less horsepower. This is the same reason manufacturers chase weight reduction as hard as they chase engine output.
What's the difference between hp/ton and hp per 1,000 lb?
They're the same ratio expressed at different scales. hp/ton divides by weight in tons (2,000 lb units), while hp per 1,000 lb divides by weight in half-ton units — so the hp per 1,000 lb figure is always exactly half the hp/ton figure. Both are common in automotive media; this calculator shows both simultaneously so you can use whichever your source material references.