Horsepower ↔ wheel horsepower converter
The dyno measures at the wheels; the spec sheet brags at the crank. Convert between the two with realistic drivetrain-loss figures.
Result
Losses are typical ranges, not physics — transmission type, tire size, and even dyno brand move the number. The honest answer is a dyno sheet.
Why wheel and crank horsepower differ
Manufacturers quote power at the crankshaft, before the transmission, driveshaft, and differential each take their cut as heat and friction. A chassis dyno measures what actually reaches the tires — which is why a "495 HP" car typically dynos in the mid-430s at the wheels on a RWD setup.
Typical drivetrain losses
- FWD: ~10% — the shortest path from crank to tire.
- RWD: ~12–15% — add a driveshaft and rear differential.
- AWD: ~18–22% — transfer case and two diffs cost real power.
Compare your numbers against real dyno results from documented builds — same model, same mods, no guessing.
Got a dyno sheet?
Log your pulls on a free build profile and your numbers join the platform's dyno database — proof beats bench racing.
- One link for your whole build — bio, forums, group chats
- Mods, costs, and dyno history tracked over time
- Followers, views, and a spot on the rankings
- Print a QR sticker — anyone who scans sees the full story
No credit card. Sixty seconds to set up.