Determine Frame Size

The right frame size is the most important factor when buying a bike. Our calculator helps you find the perfect size in seconds.

How to measure your inseam

The inseam is the most important measurement for frame size. It's more accurate than body height alone because it accounts for individual proportions.

1. Stand barefoot with your back against a wall.
2. Clamp a book or spirit level horizontally between your legs – as high as possible, like a saddle.
3. Measure the distance from the top of the book to the floor.
4. Repeat the measurement 2–3 times and take the average.

The formulas behind the calculator

Depending on the bike type, the inseam is multiplied by a different factor. These factors are based on decades of cycling industry experience:

Additional factors

Riding style

Sporty riders tend to choose a smaller frame (–1 cm) for a more aggressive position. Comfort riders pick the next bigger frame (+1 cm) for a more upright posture.

Arm length & torso

Longer-than-average arms or a long torso allow a slightly larger frame. Shorter proportions require a smaller frame. Our calculator accounts for these values when entered.

S / M / L – Manufacturer sizes

Many manufacturers use letter sizes instead of centimeters. Our calculator also shows the matching letter size. Note: exact ranges vary by manufacturer – always check the specific bike's size chart.