Saddle Height Calculator
This saddle height calculator turns your inseam into a bike saddle height. Enter your inseam in cm or inches and it shows the distance from the bottom bracket to the top of the saddle, using the LeMond method (inseam × 0.883) or the 109% method (inseam × 1.09, minus your crank length). It recalculates as you type, and everything runs in your browser.
How to measure your inseam for saddle height
Your inseam is the only measurement the calculator needs, so take it carefully.
- Stand barefoot with your back against a wall and your feet about shoulder-width apart.
- Push a hardback book up between your legs, snug against your body, with its spine against the wall. Keep it level.
- Measure from the floor to the top of the book. Do it twice, or ask someone to help.
- Type the number into the Inseam field. Pick cm or inches with the Units toggle first, so the label matches your tape.
How to measure saddle height from the bottom bracket
The result is a bottom bracket to saddle height. That is the distance from the centre of the bottom bracket, the axle the crank arms bolt onto, to the top of the saddle. The side-view diagram under the result marks both points, and Where to place the tape repeats the steps for the formula you chose.
- Hook the end of a tape measure on the centre of the bottom bracket axle.
- Run it straight up along the line of the seat tube to the top of the saddle.
- Read the figure and compare it with the Saddle height result.
- Raise or lower the seatpost until the two numbers match, then tighten it.
LeMond vs 109% saddle height method
Both methods start from your inseam. They differ in what they measure and whether crank length matters. Open Tweak formula to switch between them.
- LeMond multiplies your inseam by 0.883 and gives the bottom bracket to saddle figure directly. It is the default.
- 109% multiplies your inseam by 1.09 to get the pedal-to-saddle distance. The calculator then subtracts your Crank length (mm), so the result is still measured from the bottom bracket. The default is 172.5 mm and the field accepts 100 to 250.
The two usually land within a centimetre or two of each other. Here are three worked examples:
| Inseam | Method | Crank length | Saddle height |
|---|---|---|---|
| 82 cm | LeMond | not used | 72.4 cm |
| 82 cm | 109% | 172.5 mm | 72.1 cm |
| 32 in | LeMond | not used | 28.3 in |
Adjust your saddle height in small steps
Treat the result as a starting point, not a bike fit. Set the saddle to the figure, then change it by 2 to 3 mm at a time and go for a ride before moving it again. One small change per ride makes it clear what helped. If a setting feels wrong, go back to the last one that felt right.
Frequently Asked Questions
How do I calculate saddle height from inseam?
Multiply your inseam by 0.883 for the LeMond method, which gives the distance from the centre of the bottom bracket to the top of the saddle. For an 82 cm inseam that is 72.4 cm. The calculator above does this as you type, in cm or inches.
What is the LeMond saddle height formula?
The LeMond saddle height formula is inseam × 0.883, measured from the centre of the bottom bracket to the top of the saddle along the seat tube. It is the default here because it needs only one measurement and no crank length.
How does the 109 percent method work?
The 109% method multiplies your inseam by 1.09 to get the distance from the pedal axle, at the bottom of its stroke, to the top of the saddle. Subtract your crank length to get the bottom bracket to saddle figure. With an 82 cm inseam and 172.5 mm cranks, that is 82 × 1.09 = 89.4 cm, minus 17.25 cm, which is 72.1 cm.
How do I measure saddle height from the bottom bracket?
Hook a tape measure on the centre of the bottom bracket, which is the axle the crank arms bolt onto. Run it straight up along the seat tube to the top of the saddle and read the number. Compare it with the Saddle height result and move the saddle until they match.
Does crank length change saddle height?
Only in the 109% method. That method works out the pedal-to-saddle distance first, so a longer crank means a smaller bottom bracket to saddle height. The LeMond method ignores crank length. Open Tweak formula and choose 109% to enter your Crank length (mm), usually stamped on the back of the crank arm.
How high should my bike seat be?
There is no single right answer, but a common starting point is the LeMond figure, 88.3 percent of your inseam, measured from the bottom bracket to the top of the saddle. The result here is that starting figure for your leg length. Adjust in small steps and ride it before changing again, because the right height varies from rider to rider.
What units does the saddle height calculator use?
Choose cm or inches with the Units toggle. The Inseam field and the Saddle height result both switch to the unit you pick. The crank length is always in millimetres, and the result is rounded to one decimal place.
Is this a bike fit?
No. It gives a starting point from one measurement. A professional bike fit looks at your whole position on the bike, which a formula cannot do. Treat the number as a first setting, then adjust to what feels comfortable.
Recommended
-
Topeak JoeBlow Sport III Floor PumpPump the tires to the right pressure before the first ride on your new saddle height.
-
CXWXC Bike Repair StandClamp the bike level and steady while you set the saddle to your number and nudge it a few millimetres.
-
Polar H10 Heart Rate Chest StrapWear it on your first rides at the new saddle height and see whether your legs and heart rate feel easier.
Helps keep the tools free. ✨
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