Bike Size Chart: Find Your Frame Size
Compare road, gravel, hybrid, and kids bike sizes by height and inseam. Use the calculator for a personalized recommendation across Trek, Giant, and Specialized.
All bike types
Road, gravel, hybrid, and kids charts in one place.
Cm & inches
Every chart shows both metric and imperial measurements.
Interactive
Use the calculator to narrow to one or two likely sizes.
Model geometry is a reference check; sizing comes from the available size chart rows.
Enter your measurements to see your recommended size, backup size, confidence, and why it fits.
How to measure yourself for a bike
Accurate measurements are the foundation of good bike fit. These two measurements are all you need to use the charts below and the calculator.
How to measure your height
Stand barefoot against a wall, heels touching. Place a book on your head, flat against the wall. Mark the wall at the bottom of the book. Measure from floor to mark in cm or inches.
How to measure your inseam
Stand barefoot with feet 6-8 inches apart. Place a book between your legs, spine up, pressed firmly against your crotch (simulating saddle pressure). Measure from the top of the book to the floor. This is your cycling inseam — not your pants inseam.
Standover clearance check
Your inseam should be at least 2-3cm (about 1 inch) greater than the bike's standover height for road bikes, and 5-7cm (2-3 inches) for mountain bikes. This ensures you can stand over the top tube with both feet flat.
Bike size charts by type
Each chart maps rider height and inseam to the recommended frame size. Use these as a starting range, then confirm with the calculator or a test ride.
Road bike size chart
Gravel bike size chart
Hybrid & commuter bike size chart
Bike wheel size chart
Sizing tips
Charts give you a range. These tips narrow it down.
Between two sizes?
Go smaller for a sportier, more aggressive position. Go larger for a more upright, comfort-oriented ride. Your inseam and flexibility should drive the final decision.
Don't match by label alone
A 'Medium' in Trek is not the same as a 'Medium' in Giant or Specialized. Always match by the brand's published height range, not the size label.
Inseam beats height
Two riders of the same height can need different frame sizes if their inseams differ by more than 2 inches. Standover clearance is non-negotiable for safety.
Use the calculator for precision
The charts on this page give you a range. The calculator narrows it to one or two sizes by cross-referencing your height, inseam, bike type, and brand.
Brand sizing comparison
Go deeper with brand-specific charts
Bike sizing FAQ
Short answers for the most common bike sizing questions.
What size bike do I need for my height?
Use the road bike chart above: 5'6"–5'9" → 54–55cm (M), 5'9"–6'0" → 56–58cm (L). For mountain bikes, 5'6"–5'10" → M (17–18"). For hybrid bikes, same height → M (17–18"). Always confirm with inseam.
How do I measure myself for a bike?
Measure your height barefoot against a wall. Measure your inseam by placing a book between your legs (spine up) and measuring from the top of the book to the floor — this is your cycling inseam, not your pants size.
Are bike sizes the same across brands?
No. Trek M (54cm) ≈ Giant M ≈ Specialized 54cm by height range, but the actual frame geometry differs. Trek offers an ML half-size that Giant and Specialized don't. Always match by the brand's published height range.
Should I use cm or inches for bike sizing?
Road bikes are typically sized in cm (frame size). Mountain and hybrid bikes are often sized in inches or alpha sizes (S/M/L). Kids bikes are sized by wheel diameter. Use the chart above for cross-reference.
What if my height and inseam suggest different sizes?
Trust your inseam for standover safety first. If your inseam is short for your height, go with the smaller frame. If your inseam is long, you have more flexibility — prioritize reach and stack for your riding style.