The Bike List

Bike Frame Sizing and Fitting Guide

Your bike size is important to get right as, just like shoes, the same size in one brand might be different to another. Too big and you'll fight to stay in control, too small and you'll find yourself with a sore back, bum or knees by the end of a ride.

Unless you know your exact fit, it can be hard to know which bike to go for online, or how to set up your dream bike after buying via the web. If you are in any doubt, head to your nearest bike shop, ride the bikes of your choice and benefit from their staff's expert fitting advice.

If possible try at least three of four similar sized bikes from different manufacturers to compare the reach (distance between you and the handlebars) and if possible the ride too. Before trying any bikes make sure you raise the saddle to the correct height. You'll probably have an idea which feels most comfortable / suits your needs best but if it isn't clear cut the following step-by-step bike fit guides should help.

Step-By-Step  Bike Fit Guides

Mountain Bikes

Road Bikes

Commuting / Town / Hybrid Bikes

Professional Bike Fit

It's not just pro riders who benefit from a professional bike fit. For anyone who enjoys riding their bike regularly a well-fitting bike will make you faster, more efficient, increase your comfort and reduce your chance of knee, back or arm injury.

The Bike List paid a visit to Andy Brooke from Bike Science in Derby to find out if their level 2 fit is worth the £175 price tag. Bike Science recommend this level of fit for people who "already have a bike and are looking to optimise their position for best comfort and power output."

Click here to

Beat back ache on a bike

Suffering from back ache whilst riding? Read our guide on how to beat it.

Frame Sizes

For normal adult sized 26" wheels (or 700C road / hybrid bike wheels), size is determined by frames size (kids bikes are determined by wheel sizes with appropriate age ranges attached).

Frame size is measured from the top where the seat post slots in, down to the bottom bracket (the centre of the axle carrying the pedal arms). In the UK and USA this is measured in inches, while in Europe it is often in centimetres. Some sizings can be different as manufacturers measure from different places, such as from the middle of the top tube intersection and the seat tube. If in doubt ask the manufacturer where the measurements are taken from, or take a tape measure with you to the shop.

Frame Size   Inside leg (minimum size) Person Size
22"-23" 32"+ 6ft +
20" 29"  5ft 10"
18" 27"  5ft 6"
16" 25" 5ft 4"
14" 23.5"  5ft 2"


Sizing your bike

Road / Racing Bikes

Stand flat footed on the ground and look for a minimum of 1" between yourself and the top frame tube.

Mountain Bikes

Stand flat footed on the ground and look for a minimum of 3" between yourself and the top frame tube.

Can't try the bike for real?

Here's how to estimate your frame size without having to sit on the bike.

1. Measure your inside leg measurement to the floor (wearing the shoes you would wear for biking)
2. Subtract 3" for a mountain bike or 1" for a road bike
3. Subtract a further 10" (the average distance from the bottom bracket to the ground). This figure is the maximum frame size you'll need.

As bikes get bigger height-wise, they also get longer, so make sure that you can still comfortably reach the handlebars and manage all the controls. Get a bike too big for you and it can be dangerously difficult to control. The distance from the saddle to the handle bars increases by an average of 1" for every 2" increase in frame size. Saddles are adjustable by between 4" and 10" and handlebars can be moved up and down, elongated or shortened so you can tailor the bike to fit you perfectly.


Kids bikes are usually grouped into age categories, but there's no need to stick to it rigidly and force your tall 6 year old on to a 6 year old's bike. If your little Johnny or little Suzie feels comfy and not too stretched out while sitting on the bike with the ball of their foot touching the floor, can turn the handlebars without hitting their knees, operate the gear and brake levers with ease, there is nothing wrong with buying a bike from a bigger or smaller age category.

12" Wheel - ages 2½ to 4
14" Wheel - ages 3 to 5
16" Wheel - ages 5 to 7
20" Wheel - ages 7 to 9
24" Wheel - ages 9 to 11
26"+ Wheel - ages 11+ (adult cycles)

When buying 12" & 14" wheel 'first bikes' there are many toys bikes, sometimes cartoon and character branded bikes, which may not feature high quality parts. They often feature plastic bushes instead of steel bearings in the hubs and main cog assembly. Whilst sometimes this works well and spare back up parts are also provided, plastic bushes commonly wear out very quickly. For a quality ride look for bikes that use ball bearings in the hubs and main cog assembly.

Once your little angel has learnt to ride without stabilisers (often at about age 5) they can move up to a 16" wheel cycle which are not normally fitted with stabilisers, but they can be added if needed.

With 20" wheel bikes and above, you start to get different frame sizes. This gives smaller, confident riders the advantage of fitting on to a larger wheeled bike. Here it's tempting to buy little Johnny or little Suzie a larger bike that they can grow into...which they will, but in the meantime they will find it a difficult bike to control which can be very dangerous, particularly where roads are involved.