Gear Ratio Calculator
Calculate vehicle speed at any RPM in each gear. Perfect for transmission swaps, tire changes, and final drive selection.
Display Unit
Tire Size
275/40R18 677.2 mm (26.66" diameter)
Transmission
1st
2nd
3rd
4th
5th
6th
7th
8th
Engine
Speed at Redline (7,000 RPM)
1st 58.7 kmh
2nd 88.0 kmh
3rd 131.4 kmh
4th 165.9 kmh
5th 215.3 kmh
6th 276.6 kmh
7th 329.7 kmh
8th 414.8 kmh
Top speed in 8th gear: 414.8 kmh (at redline, ignoring power limits)
Speed vs RPM Table
| RPM | 1st | 2nd | 3rd | 4th | 5th | 6th | 7th | 8th |
|---|---|---|---|---|---|---|---|---|
| 1,000 | 8.4 | 12.6 | 18.8 | 23.7 | 30.8 | 39.5 | 47.1 | 59.3 |
| 2,000 | 16.8 | 25.1 | 37.5 | 47.4 | 61.5 | 79.0 | 94.2 | 118.5 |
| 3,000 | 25.2 | 37.7 | 56.3 | 71.1 | 92.3 | 118.6 | 141.3 | 177.8 |
| 4,000 | 33.5 | 50.3 | 75.1 | 94.8 | 123.0 | 158.1 | 188.4 | 237.0 |
| 5,000 | 41.9 | 62.9 | 93.8 | 118.5 | 153.8 | 197.6 | 235.5 | 296.3 |
| 6,000 | 50.3 | 75.4 | 112.6 | 142.2 | 184.5 | 237.1 | 282.6 | 355.5 |
| 7,000 | 58.7 | 88.0 | 131.4 | 165.9 | 215.3 | 276.6 | 329.7 | 414.8 |
All speeds in KMH
Gear Range Visualization
1st
2nd
3rd
4th
5th
6th
7th
8th
0 207 415
kmh
Understanding Gear Ratios
The Formula
Speed is calculated using:
Speed = (RPM ร Tire Diameter ร ฯ) รท (Gear Ratio ร Final Drive ร 336.13)
This gives exact results based on pure physics โ the same formula your ECU uses.
Gear Ratio Effects
- Lower ratio (0.6) = Higher top speed, less acceleration (overdrive)
- Higher ratio (4.0) = Lower top speed, more acceleration (1st gear)
- Final drive affects ALL gears equally
Common Uses
- Planning a transmission swap
- Choosing final drive ratio for track vs street
- Checking speedometer accuracy after tire change
- Calculating cruise RPM at highway speeds