Best car gear guide

How to Calculate Gear Ratio of Car

Gear Ratio is the ratio of the output torque to the input torque of an engine. Gear ratio can be used to calculate car horsepower. Car horsepower is a measure of engine performance.

What is Gear Ratio?

Gear ratio is the number of gears in a gearbox, as well as the number of teeth on the gear wheel. Gear ratio affects how fast a car can go and how smooth the gear changes are.

How to calculate Gear Ratio of Car

Gear ratio is the relationship between the number of teeth on the wheel in front and the wheel in back. It’s expressed as a fraction and typically ranges from 1.00 to 1.29, with 1.00 representing a direct drive between the two wheels.

The gear ratio can be used to calculate the power output and speed of a car at any given moment by dividing the engine’s horsepower by the wheel’s rotational speed. It can also be used to determine how fast a car is moving overall.

There are several ways to calculate gear ratio, but the most common is to use a calculator or a physics textbook. If you’re not familiar with gears and ratios, you can also try calculating it using basic math skills.
For example, if your car has a 4-speed manual transmission and an engine with 700 horsepower, its gear ratio would be 2.73. This means that for every time the engine turns 700 revolutions, the car will turn 2 revolutions with its wheels (or 3202 rpm).

When to change Gear Ratio of Car

When to change gear ratio of your car can be tricky. The speedometer may not always reflect the actual speed of the car and changing gears may not always result in a faster trip.

To calculate the gear ratio of your car, first use the equation below:
Gear Ratio = (Speedometer Reading in MPH) / (Engine Horsepower)

For example, if you are driving at 60 mph and your speedometer says you are going 50 mph, then your gear ratio would be 1.5. This means that you are driving at 50% of the horsepower of your engine.

If you want to increase the speed of your car, you will need to increase the gear ratio by increasing the number above it on the equation. For example, if your gear ratio is set at 1.5 and you want to go 80 mph, then your gear ratio would be 2.0.


Gear ratio is a key concept when driving a car. It tells you how much power your engine is putting out to propel the vehicle forward, and it’s usually expressed in terms of numbers like 1:1 or 2:1. Knowing your gear ratio is important because it affects how fast you can go and how smoothly the car will drive. In this article, we’ll show you how to calculate your gear ratio and use that information to improve your driving experience.

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