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Bike Frame Size Calculator

Find your road, gravel, mountain, hybrid or e-bike frame size from your height and inseam, in cm or inches, with S/M/L sizing.

Bike type

Stand barefoot against a wall, pull a hardback book up firmly between your legs, and measure from its top edge to the floor.

Your size

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–frame size from inseam
–saddle height (BB to top of saddle)

How the bike frame size calculator works

What size bike frame do I need? Stand barefoot against a wall with your feet 15 to 20 cm apart. Place a hardback book between your legs, spine up, and pull it up firmly as if it were a saddle. Measure from the top of the book to the floor.

  1. Road and gravel frame size (cm) ≈ inseam (cm) × 0.665 (c-t, center to top of seat tube).
  2. Mountain bike frame size (inches) ≈ inseam (cm) × 0.226. Hybrid and city bikes use ≈ inseam × 0.685 (cm).
  3. We cross-check the result against typical height ranges for XS to XXL sizes. Always confirm against the brand’s own size chart: reach and stack vary between models.

Results are estimates to help you plan and compare. Always follow your manufacturer's specifications, especially for charging, tire pressure and load limits. Found a problem with this tool? Let us know.

Frame size questions, answered

How do I measure my inseam for a bike?

Stand barefoot against a wall with your feet 15 to 20 cm apart. Place a hardback book between your legs, spine up, and pull it up firmly as if it were a saddle. Measure from the top of the book to the floor.

What if I am between two bike sizes?

Choose the smaller size if you prefer a more upright, playful ride or have shorter arms. Choose the larger size for more stability at speed or if you have a long torso. A test ride is the best tie-breaker.

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