FietsRadar

Where is the frame number on your bike?

Turn your bike over: the frame number is usually under the bottom bracket, where the pedals meet the frame. Note it now, because without a frame number a stolen bike is almost impossible to trace.

Where to look

  1. under the bottom bracket, the most common place
  2. on the rear dropout, by the rear axle
  3. on the seat tube, below the saddle
  4. on the head tube, at the front of the frame

The number is stamped into the metal, sometimes under paint or dirt. Clean the spot and use your phone’s torch.

E-bikes

On an e-bike the frame number is usually in the same places, sometimes also on a sticker. The battery has a serial number of its own. Note that too: batteries are often stolen and sold on their own, and they are the most expensive part of the bike.

Cannot find it?

  • the receipt or invoice
  • the warranty or the shop’s paperwork
  • your bike insurance
  • an old photo of the frame

The frame number is not the number on your key. A key number only identifies the lock.

Note it now

A frame number is easiest to find while the bike is still outside your door. Put it in FietsRadar with a few photos and the battery numbers, and you have everything to hand if you ever need to report it.

Updated 1 October 2026