Frame Size Chart Bike
Bike sizing depends on the type of bike. Enter your inseam and height, choose road, gravel, hybrid, city or mountain bike, and the calculator gives a starting frame size in centimetres or inches using the common inseam formulas, a letter size, an estimated saddle height and a standover check — plus wheel sizes for children’s bikes.
Bike frame size calculator
Bike Sizing & Fit Pack
Printable bike frame size charts for road, hybrid, gravel and mountain bikes, a kids’ bike size chart, a bike fit measurement worksheet and an Excel family bike size log.
- Frame size chart (PDF)
- Kids’ chart (PDF)
- Fit worksheet (DOCX/PDF)
- Family bike log (XLSX)
Formats: PDF, XLSX, DOCX. Instant download after payment (link valid 72 hours, up to 5 downloads). AI-assisted: the templates were drafted with AI help and reviewed and laid out by Kedop.
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Inseam formulas by bike type
| Bike type | Formula (inseam in cm) | Sizes usually given in |
|---|---|---|
| Road | Inseam × 0.67 | cm (e.g. 54) or XS–XL |
| Gravel / cyclocross | Inseam × about 0.665 | cm or XS–XL |
| Hybrid / fitness | Inseam × about 0.66 | cm, inches or S–XL |
| City / step-through | Inseam × about 0.66 | cm or S–L |
| Mountain | Inseam × 0.226 (gives inches) | S–XL (older bikes in inches) |
These formulas estimate the seat tube length. Modern frames with sloping top tubes often use “virtual” sizes, and brands measure differently, so treat the result as a starting point.
General frame size chart by height
| Height | Letter | Road (cm) | Hybrid (in) | Mountain (in) |
|---|---|---|---|---|
| 150–160 cm (4′11″–5′3″) | XS | 47–50 | 13–14 | 13–14 |
| 160–170 cm (5′3″–5′7″) | S | 50–53 | 15–16 | 15–16 |
| 170–180 cm (5′7″–5′11″) | M | 53–56 | 17–18 | 17–18 |
| 180–190 cm (5′11″–6′3″) | L | 56–59 | 19–20 | 19–20 |
| 190 cm+ (6′3″+) | XL | 59–62 | 21–22 | 21–22 |
How to measure inseam
- Stand barefoot against a wall, feet 15–20 cm apart.
- Pull a hardback book up firmly between your legs, spine upwards, as a saddle would sit.
- Mark the top of the spine on the wall.
- Measure from the floor to the mark.
- Repeat and average.
Saddle height
A common starting saddle height is inseam × 0.883, measured from the centre of the bottom bracket to the top of the saddle along the seat tube. At the bottom of the pedal stroke your knee should be slightly bent — about 25–35 degrees. Too low wastes power and strains knees; too high makes your hips rock. Adjust in small steps.
Standover and reach
Standover is the clearance between you and the top tube when you stand over the bike: a few centimetres for road bikes, more for mountain bikes where you need room to move. Reach — how far forward the handlebars are — determines comfort as much as frame size. If a bike feels stretched, a shorter stem or higher handlebars can help; if it feels cramped, a longer stem. Big changes mean the frame size is wrong.
Kids’ bike sizes
| Wheel size | Typical age | Typical inseam |
|---|---|---|
| 12 in | 2–4 | 35–45 cm |
| 14 in | 3–5 | 40–50 cm |
| 16 in | 4–6 | 45–55 cm |
| 20 in | 6–9 | 50–62 cm |
| 24 in | 8–12 | 58–72 cm |
| 26 in / XS adult | 11+ | 65 cm+ |
Children’s bikes are sized by wheel diameter. Use inseam rather than age, because children grow at different rates.
Worked example
A rider 176 cm tall with an 81 cm inseam wants a gravel bike. The calculator estimates a 54 cm frame (81 × 0.665), letter size M, and a saddle height of about 71.5 cm. For a hybrid it suggests a 53 cm (about 21 in) frame, and for a mountain bike an 18.3-inch frame. They compare the stack and reach of two 54 cm gravel bikes and book a test ride.
Women’s and unisex frames
Some brands make women’s-specific frames with shorter reach and different contact points, while others offer unisex frames in a wide size range and change saddles, bar widths and stem lengths instead. Riders of any gender should choose by fit — inseam, reach and stack — rather than labels. Smaller riders may find that brands using 650b or 27.5-inch wheels on small frames give better handling and toe clearance.
Adjustments that fine-tune fit
| Adjustment | Effect |
|---|---|
| Saddle height | Leg extension and pedalling efficiency |
| Saddle fore-aft | Knee position over the pedal |
| Stem length | Reach to the handlebars |
| Stem angle / spacers | Handlebar height and comfort |
| Handlebar width | Shoulder comfort and control |
| Crank length | Knee and hip angles, especially for small riders |
A professional bike fit can fine-tune these for regular riders, especially if you have pain or ride long distances.
Test ride checklist
- Stand over the bike with both feet flat.
- Set the saddle height before riding.
- Check you can reach brakes and shifters comfortably.
- Ride for at least 10–15 minutes, including starts and stops.
- Look for relaxed elbows and shoulders.
- Ask the shop about stem and handlebar adjustments.
Privacy
The calculator runs in your browser and stores nothing.
Frequently asked questions
How do I calculate bike frame size?
Multiply your inseam by the factor for your bike type — 0.67 for road bikes in cm, 0.226 for mountain bikes in inches.
What size bike for 5′10″?
Usually medium to large: about 54–56 cm road, 17–19 in mountain, depending on inseam.
Is inseam or height more important?
Inseam is more precise; height is a quick guide.
How much standover clearance do I need?
A few centimetres for road bikes and more for mountain bikes.
What size bike for a 7-year-old?
Often 20-inch wheels; check inseam against the maker’s chart.
Should I size up for a child to grow into?
No; an oversized bike is harder to control. Choose one that fits now, with some saddle adjustment for growth.
What does a 54 cm frame mean?
The seat tube length (or virtual equivalent), commonly a medium road bike.
Do hybrid bikes use cm or inches?
Both are common; check the brand’s chart.
Can I ride a frame one size off?
Often yes, with stem and saddle adjustments, but test ride first.
What is standover height?
The height of the top tube where you straddle the bike; you need some clearance above it.
Is my data stored?
No, it runs in your browser.