How to Set Saddle Height: Formula, Knee Angle & Crank Length

The most widely used starting formula multiplies your cycling inseam by 0.883. It was popularised by Greg LeMond and his coach Cyrille Guimard and is still the default in most calculators:

Example: an 820 mm inseam gives 820 × 0.883 ≈ 724 mm. A 790 mm inseam gives ≈ 698 mm.

The formula is only as good as the inseam you feed it. Measure it the cycling way — barefoot, with firm upward pressure, floor to crotch — not from your trouser length. See how to measure your inseam for the book-against-the-wall method.

Discipline offsets

Different kinds of riding trade a little pedalling efficiency for control or comfort. FitInspector applies these small offsets to the 0.883 result:

Crank length correction

Your leg is most extended when the pedal is at the bottom, so what matters is roughly saddle height plus crank length. FitInspector’s calculation assumes a 170 mm crank; if yours differs, the calculator corrects the saddle 1:1 — its method, not a universal rule:

Crank length is usually stamped on the inside of the crank arm, next to the pedal thread. More in crank length and saddle height.

1. Put the bike on level ground or a trainer, with the seatpost clamp tight.
2. Find the centre of the bottom bracket — the axle the cranks rotate around.
3. Hook the tape on the axle centre and run it up along the seat tube line to the top of the saddle, at the point where you actually sit (roughly the middle of the saddle, not the nose).
4. Compare with your calculated number. If you need to change it, move the saddle in steps of 3–5 mm, mark the seatpost with tape, and ride a few times before the next change.

A formula cannot see your body. The usual cross-check is the knee angle at the bottom of the pedal stroke (crank at 6 o’clock). Two published ranges are commonly used, each tied to how the angle is measured:

• Static, sitting still with the pedal at the bottom: about 25–35° of knee bend, as widely cited from Holmes et al. (1994).
• Dynamic, filmed while pedalling: about 30–40° of knee bend (Ferrer-Roca et al., 2012).

Less bend than the range usually means the saddle is too high; more bend means it is too low. Read the full explanation in our knee angle guide, or take a side-on photo or video and let the riding position check measure it for you.

109% of inseam. An older method sets the distance from the pedal axle (pedal at the bottom) to the top of the saddle at 109% of inseam, based on Hamley & Thomas (1967). Ferrer-Roca et al. (2012) found that inseam percentages alone did not reliably put well-trained cyclists into the 30–40° dynamic knee range, which is why a knee-angle check is worth doing whichever formula you start from.

The heel method. Pedal backwards with your heel on the pedal; the saddle is about right when your leg is just straight at the bottom without rocking your hips. It is quick and needs no tools, but shoe sole thickness and foot position make it imprecise.

Enter your height, inseam and discipline in the bike fit calculator to get your saddle height together with handlebar width and a frame size suggestion. Then confirm the result on the bike with the position check. Running a bike shop? FitInspector can also be added to your online store.