What “saddle size” actually means
Unlike frames or wheels, bike saddles are not sold in a universal size system. When people search for a saddle sizes chart, they usually mean saddle width, which brands typically list in millimetres. Many brands offer the same model in two or three widths, and some also vary length, shape and padding.
Because there is no industry-wide standard, treat any chart as general guidance. A “143 mm” saddle from one brand may not feel the same as a “143 mm” saddle from another, since shape, flex and where the width is measured can differ.
The main thing a saddle needs to do is support your weight on your sit bones (the bony points at the bottom of your pelvis) rather than on soft tissue. Width is the first step toward that, but shape and riding position matter as well.
Saddle width chart: matching sit bones to saddle width
Many fitters and manufacturers start from your sit bone width and add a margin to allow for padding and for how upright you sit. The margin varies by brand and riding position, so the table below is a rough starting point only. Check the sizing advice of the brand you are buying.
| Measured sit bone width | Typical starting point for saddle width |
|---|---|
| Narrower sit bones (about 100 mm or less) | Narrower saddles, often around 130-140 mm |
| Medium sit bones (about 100-125 mm) | Mid-width saddles, often around 140-150 mm |
| Wider sit bones (about 125 mm or more) | Wider saddles, often 150 mm and up |
Riding position changes the picture. A more upright position (commuter, hybrid, relaxed touring) usually puts more weight on the sit bones and often suits a wider, more padded saddle. A more aggressive, forward-leaning position rotates the pelvis and often works with a narrower, flatter saddle. These are tendencies, not rules.
How to measure your sit bones at home
You can get a decent estimate without a shop visit:
- Place a piece of corrugated cardboard, or a thick sheet of foam, on a hard, flat chair or step.
- Sit on it with your feet off the floor or resting on a lower step, knees bent roughly at right angles and your back upright. Lean forward slightly, as you would on a bike.
- Stay still for a few seconds so the sit bones leave an impression, then stand up.
- Mark the centre of each dent, and measure the distance between the two marks in millimetres.
Repeat once or twice to check you get a similar number. Some shops use a gel or memory-foam measuring pad, which does the same job more precisely. If your numbers are unclear, a bike shop’s sit bone measurement is usually quick and often free or inexpensive.
Beyond width: shape, length, cutouts and padding
Width alone will not guarantee comfort. Other things to consider:
- Shape profile: Flat saddles allow more movement and suit some riders. Curved saddles hold you in place more. Neither is universally better.
- Cutouts and channels: A central cutout or channel is intended to reduce pressure on soft tissue. Some riders find it helps; others prefer a solid saddle. Try before committing if you can.
- Length: Short-nose saddles are popular for riders who want to rotate forward without pressure at the front. Longer saddles give more positions to shift into.
- Padding: More padding is not always more comfortable on longer rides. Firm saddles with good shape can feel better over time than very soft ones, which can allow you to sink and cause pressure.
- Rider anatomy: Pelvic anatomy differs between riders, and many brands make saddles designed around different anatomies. Choose according to how you feel, not the label.
Do all bike saddles fit all bikes?
In most cases, yes, within limits. Most saddles attach with two parallel rails underneath, which clamp into the seatpost head. The common rail diameter is 7 mm (round), and many modern seatposts also accept oval rails; check your seatpost clamp if you are unsure, because some saddles use wider or differently shaped rails that not every clamp will take.
Other points to check:
- Seatpost clamp type: Single-bolt and two-bolt designs both work with standard rails, but they adjust tilt differently.
- Integrated or proprietary posts: Some frames use special seatposts or saddle mounts, which limit your choices.
- Rail length and range: Rails need enough length to let you adjust fore and aft. See our guide to setting saddle height for how height and setback interact.
Checking the fit once the saddle is on the bike
Fit the saddle roughly level, then adjust. Small changes in tilt and fore-aft position can change how a saddle feels more than you might expect, so adjust one thing at a time and ride for a few outings before changing again.
A saddle that is level (or very close to it) and positioned so you are not constantly sliding forward or backward is usually a good starting point. Setting the correct height first is important, since a saddle that is too high or too low can make a perfectly good saddle feel wrong. Our guide to how to set your saddle height walks through several methods.
Signs a saddle is the wrong size or shape
Some adjustment period is normal when you are new to riding or after a long break. Persistent problems are a sign to look again:
- Pressure or soreness on soft tissue rather than the sit bones
- Numbness or tingling that does not go away after a short change of position
- Skin rubbing on the inner thighs or along the edges of the saddle, which may point to a saddle that is too wide or a saddle height that is too high (see preventing saddle chafing and sores)
- Sit bones hanging off the sides of the saddle, suggesting it is too narrow
If you have ongoing pain, numbness or any symptoms that worry you, speak to a doctor or a qualified bike fitter instead of trying to fix it by guesswork.
Frequently asked questions
How do I measure saddle size for a rider?
Measure the distance between the sit bones using cardboard or a foam pad, then use that figure as a starting point for choosing a saddle width. Allow for your riding position and for the sizing guidance of the brand.
How high should the saddle be according to the LeMond method?
The LeMond method multiplies your inseam by 0.883 to estimate the distance from the centre of the bottom bracket to the top of the saddle. It is a starting point, not a final setting. See how to set your saddle height for a worked example.
How do I measure my sit bones?
Sit on corrugated cardboard or a memory-foam pad, lean slightly forward, and measure between the two impressions. A bike shop can also measure them for you.
Do I need a different saddle for each bike?
Not necessarily. If the saddle suits your anatomy and riding position, it can move between bikes, though a more upright bike may suit a different shape than a more aggressive one.