🏎️ RPM Calculator
Calculate engine RPM based on speed, gear ratio, and tire size
🌀 RPM Calculator
Common Driving Scenarios
Highway Cruising (70 MPH)
3.08 ratio, 28" tires:2,600 RPM
3.42 ratio, 28" tires:2,880 RPM
3.73 ratio, 28" tires:3,140 RPM
4.10 ratio, 28" tires:3,450 RPM
City Driving (35 MPH)
3.08 ratio, 28" tires:1,300 RPM
3.42 ratio, 28" tires:1,440 RPM
3.73 ratio, 28" tires:1,570 RPM
4.10 ratio, 28" tires:1,725 RPM
Common Tire Diameters
Passenger Cars
205/55R1624.9"
225/60R1626.6"
235/65R1729.0"
Performance Cars
245/40R1825.7"
275/35R1926.6"
295/30R2027.0"
Trucks/SUVs
265/70R1731.6"
285/75R1632.8"
33x12.50R1533.0"
Formula & Tips
RPM Calculation Formula:
RPM = (MPH × Gear Ratio × 336) ÷ Tire Diameter (inches)
Tips for Optimal RPM:
- Most engines are most efficient between 1,500-2,500 RPM for cruising
- Peak torque typically occurs between 2,000-4,000 RPM
- Higher RPM increases fuel consumption and engine wear
- Lower gear ratios reduce RPM at highway speeds but hurt acceleration
- Larger tire diameter reduces RPM but may affect speedometer accuracy
How to Use
1. Enter vehicle speed in MPH or KPH
2. Input tire diameter in inches
3. Enter gear ratio for current gear
4. View calculated engine RPM instantly
Features
✓ Speed to RPM conversion
✓ Gear ratio calculations
✓ Tire size considerations
✓ Multiple unit support