Bike Size Calculator

This easy-to-use bike frame size calculator will allow you to calculate the perfect bike size for you on the basis of your measurements. You just need to put your height and your inseam into the calculator and you'll get the result.

Bike Frame Size Calculator

Measuring Your Height and Inseam

To calculate your correct bike size, you have to know a couple of body measurements. Firstly, you need to know your full height: you can easily measure this by standing with your back to a wall and making a mark level with the top of your head. Measure the distance from the mark to the floor and that's your height.

Once you've measured your height, you need to know your inseam. Stand with your back against the wall without shoes on, and put a book or a ruler between your legs at crotch level. Ask someone else to make a mark or measure the distance from the floor to the top of the book or ruler. That's your inseam measurement. Do this a few times to make sure you have it spot on.

Calculating Your Bike Frame Size

Bike frame size is the measurement between the middle of the bottom bracket to the junction of the top tube and the seat tube.

Sometimes the top tube won't be horizontal, especially on a bike with a step-through frame or a compact frame, then it's a little more complicated. If that's the case, the measurement is taken from an imaginary horizontal top tube. There can be some minor differences though, certain manufacturers take the measurement from the middle of the top tube, not the top of it, and different bikes have bottom brackets different heights of the ground. You can have two bikes with the same frame size but differing stand-over height.

To calculate your bike frame size, take your inseam in centimeters and multiply it by 0.575 for mountain bikes, 0.665 for road bikes, and 0.645 for trekking bikes. If you need to convert your measurements to inches, divide them by 2.54.

*Note: You should be aware that sizes can be very different for different models and brands, and so these frame sizes are just for information and a recommendation; you should always check with your local bike shop that your chosen frame size is correct.

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