Bike Fit Calculator

Tips for a good photo

Low-poly rider standing beside a road bike, facing a phone on a tripod with its field of view drawn out, and the phone's screen in the corner — Example rider and a typical phone camera. Facing, frame and tilt use the same pass marks the measurement applies to your photo; the lens is our advice.

What the measurement needs from your photo
Check	Aim for	Why
You	Standing beside the bike, heels together, feet flat, arms relaxed at your sides, in fitted clothing	We measure your legs, arms and torso from the joints we find in the photo
Facing	Face the phone, within 45° of square-on	Turned side-on, one arm and leg hide behind the other, and the photo gets sent back
Frame	Phone upright, a few steps back, head to feet and both wheels inside the frame	You tap a wheel to give the photo its scale, and a cropped head or foot can't be measured
Tilt	Phone at about hip height, tilted no more than 7°	A tilted phone makes whatever is closer to it look bigger, so legs and torso come out in the wrong proportion
Lens	Main camera (1×) or zoom (2×), not the 0.5× ultra-wide	Ultra-wide stretches whatever is near the edges: step back and zoom in instead

Wheel size

Use the live camera: it shows hints on screen while you set up the shot.

You can upload a standing photo of yourself next to your bike.

Height

Inseam

Discipline

Optional (improves accuracy)

Shoulder width

Crank length

This is a starting point. For a precise fit, book a session with a bike fitter.

How the calculator works

Enter your height, inseam and discipline. Saddle height starts from the LeMond/Hinault formula: inseam × 0.883, measured from the center of the bottom bracket to the top of the saddle.

A fixed offset for your discipline is then added: road 0 mm, gravel −2 mm, XC mountain bike −5 mm, touring −5 mm, cyclocross −6 mm, TT/triathlon +8 mm. Kids’ bikes use a separate, lower formula (inseam × 0.883 × 0.85) so the rider can reach the ground. No discipline offset or crank correction is applied to kids’ bikes.

Crank length is optional. The base formula assumes 170 mm cranks. If you enter yours, the saddle height changes by the difference, millimeter for millimeter: 165 mm cranks raise the saddle by 5 mm, 175 mm cranks lower it by 5 mm. The final height is rounded to the nearest millimeter.

The calculator also gives you:

handlebar width from your shoulder width;
a target torso angle for your discipline;
a frame size from standard size charts;
for road bikes, handlebar drop and saddle-to-hoods distance, from Dan Empfield’s published norms.

Treat the result as a starting point, not a final position. Change your saddle height in small steps, ride a few times between changes, and check your knee angle with the position check. To see how a saddle, stem or spacer change would move your angles before you make it, try the fit constructor.

Frequently asked questions

How do I measure my inseam for the calculator?

Stand barefoot with your back against a wall and pull a book up firmly between your legs, the way a saddle would sit. Measure from the floor to the top edge of the book. Your trouser inseam is a different, usually shorter number, so don’t use it.

Where exactly is saddle height measured?

From the center of the bottom bracket, along the seat tube, to the top of the saddle where you sit. Measuring from the floor or from the pedal gives a different number that can’t be compared with the result.

Should I change saddle height if I change crank length?

Yes, by the difference in crank length. Going from 172.5 mm to 165 mm cranks means raising the saddle by about 7.5 mm, and going to longer cranks means lowering it. The calculator applies this when you enter your crank length.

Why is the result different from my current saddle height?

The formula describes an average rider. Tight hamstrings, the stack height of your shoes and cleats, and the shape of your saddle can all move your best height by a few millimeters. If your current height differs, move toward the result gradually and check your knee angle as you go.