How it works
A walkthrough, end to end.
- 1
Enter vehicle weight (with driver) and quarter-mile trap speed.
- 2
Optional: enter ET for an alternative estimate.
- 3
See estimated flywheel HP using Huntington and Fox formulas.
Reference
HP from trap speed
Huntington: HP = weight × (mph/234)³. Fox: HP = weight × (mph/228)³.
Use cases
What you can do with this.
Drag racing
Quick HP estimate from a track pass.
Tuning verification
Cross-check dyno HP after mods.
Build planning
Target HP for a desired ¼ mile time.
EV vs ICE compare
Equal-weight HP comparison.
Project car spec
Plan power-to-weight target.
FAQ
Frequently asked.
Trap speed correlates better with peak HP because ET is sensitive to launch and gearing.
These formulas estimate flywheel HP. Wheel HP is ~10–15% lower.
No. All math runs in your browser.
Within ~5% for street-stock cars, less accurate for radically built vehicles.