728 × 90 Leaderboard

320 × 100 Mobile Banner

Gear Ratio Calculator

Calculate axle gear ratio, overall ratio, and speed at RPM.

Last updated: June 13, 2026

Calculator

Ring Gear Teeth

Pinion Gear Teeth

Tire Diameter

inches

Transmission Ratio (top gear)

Engine RPM

Results

Axle Gear Ratio3.73:1

Overall Ratio (w/ trans)2.72:1

Speed at RPM120.3 mph

At 2500 RPM in top gear

RPM at 60 mph1247 RPM

How to Use This Calculator

1Enter ring gear teeth count.
2Enter pinion gear teeth count.
3Enter tire diameter, transmission ratio, and RPM.
4View axle ratio, overall ratio, speed at RPM, and cruising RPM.

Formula Explanation

The gear ratio determines how many times the driveshaft rotates for each wheel rotation, directly affecting acceleration and top speed.

Axle Ratio = Ring Gear Teeth ÷ Pinion Gear Teeth Speed = (RPM × Tire Diameter × π) ÷ (Overall Ratio × 336 × 2)

Variables:

Ring Gear TeethNumber of teeth on the ring gear

Pinion Gear TeethNumber of teeth on the pinion gear

Overall RatioAxle ratio × Transmission gear ratio

Worked Examples

41/11 gears, 28" tires, 0.73 trans, 2500 RPM

1. Axle ratio = 41 ÷ 11 = 3.73:1
2. Overall = 3.73 × 0.73 = 2.72:1

Result: Speed at 2500 RPM: ~64 mph

Why Use This Calculator

Essential for building or modifying vehicles.
Calculate cruising RPM for highway comfort.
Compare different gear setups before purchasing.
Accounts for transmission and tire size.

336 × 280 Large Rectangle

300 × 250 Medium Rectangle

Tips & Best Practices

Lower ratios (numerically higher, like 4.10) = better acceleration.
Higher ratios (numerically lower, like 3.08) = better fuel economy.
Always recalculate when changing tire sizes.

Common Mistakes to Avoid

❌ Confusing higher and lower gear ratios.

✅ A 4.10:1 is numerically higher but called a "lower" gear (more torque multiplication). A 3.08:1 is "higher" (less multiplication, more speed).

❌ Not accounting for tire size changes.

✅ Changing tire size effectively changes your final drive ratio. Always recalculate.

Frequently Asked Questions

What gear ratio is best for towing?

For towing, a numerically higher ratio (3.73 or 4.10) provides more torque multiplication for pulling heavy loads, though it increases highway RPM.

How does gear ratio affect fuel economy?

A numerically lower ratio (like 3.08 vs 3.73) reduces engine RPM at highway speed, improving fuel economy. But it reduces low-speed acceleration.

336 × 280 Large Rectangle

300 × 250 Medium Rectangle

Embed This Calculator

Add the Gear Ratio Calculator to your website for free. Copy the code below and paste it into your HTML.

Width

Height

<iframe src="https://redicalc.com/embed/automotive/gear-ratio-calculator" width="100%" height="600" style="border:none;border-radius:12px;box-shadow:0 1px 3px rgba(0,0,0,0.1);" title="Gear Ratio Calculator — RediCalc.com" loading="lazy" allowtransparency="true"></iframe>

Preview embedFree to use · Attribution link included

Disclaimer: This calculator is provided for informational and educational purposes only. Results are estimates and should not be used as a substitute for professional advice. RediCalc.com makes no guarantees regarding the accuracy, completeness, or suitability of any calculations. Always consult a qualified professional before making financial, health, construction, or other important decisions.

160 × 600Skyscraper