Free Bike Fit & Size Calculator
Enter your height and inseam, get your perfect frame size in 30 seconds. 25 free calculators for road, mountain, kids, and every other bike type.
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Free Calculators
29
Brand Size Charts
40+
Bike Comparisons
30s
Average Time to Fit
Most Popular Calculators
Pick your bike type — get your frame size in seconds
Bike Size Calculator
Enter your height and inseam — get road, mountain, and hybrid frame sizes in seconds.
Kids Bike Size
Find the right wheel size and frame for your child based on age, height, and inseam.
Mountain Bike Size
Get your ideal MTB frame size with standover clearance for confident trail riding.
Road Bike Size
Dial in your road bike frame size for better power transfer and all-day comfort.
How It Works
1
Enter Your Measurements
Your height and inseam are all you need. We walk you through measuring both.
2
Get Your Frame Size
Our formulas match professional bike fitting standards and return your size in seconds.
3
Ride With Confidence
Take your results to the shop or compare directly with 29 brand size charts on our site.
Sizing Guides
Step-by-step guides used by thousands of cyclists every month
8 min read
Quick-reference sizing chart for every bike type — find your frame size by height in one glance.
10 min read
New to cycling? Start here — plain-English sizing advice so your first bike fits right.
9 min read
Frame, standover, and reach guidance for riders 6 ′2 ″ and above.
Popular Articles
In-depth bike fitting and sizing advice from our experts
14 min read
Age-by-age sizing charts, safety tips, and when to size up as your child grows.
15 min read
Professional fitting techniques — saddle height, reach, handlebar position, and cleat alignment.
Brand Size Charts
Official sizing guides from top bike manufacturers
Popular Comparisons
Side-by-side bike sizing analysis
Rider favorites
Top accessory picks across categories — verified live on Amazon.
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Giro
Giro Register MIPS
S 51–55 cm, M 55–59 cm, L 59–63 cm
$83.19
Shop Now →
Niterider
Niterider Lumina Micro 950
950 lm: excellent for unlit roads and trails; 24-hour Femto mode for commuting.
$56.24
Shop Now →
Kryptonite
Kryptonite Evolution Series 4 Standard
Inner dimensions: 4" x 9" (10 x 23cm). Fits frame + single wheel through U + around fixed object. Standard commute size.
$47.95
Shop Now →
Fizik
Fizik Arione R3
Available widths 142, 154 mm; fits sit-bone 120–145 mm
$132.34
Shop Now →
Elite Cycling
Elite Cycling Elite Ombra Water Bottle 550ml
Compact 550ml. Ideal for road racing and small-frame riders.
$9-15
Shop Now →
Ortlieb
Ortlieb Back Roller Pro Classic
Fits standard rear racks with 8-16mm tubular rails. Per-side mounting provides stability. Most popular touring pannier globally.
$190.00
Shop Now →
As an Amazon Associate we earn from qualifying purchases. This helps support our free calculators.
Gear & accessories
Helmets, lights, locks and the rest of the kit — sized and picked.
Why Cyclists Trust BikeSize
Every calculator is free, with no signup required — just accurate results.
Pro-Level Accuracy
Our formulas match the methods professional bike fitters use — inseam multipliers, standover ratios, and reach-stack geometry.
Every Bike Type Covered
Road, mountain, gravel, kids, e-bike, BMX, and triathlon — plus saddle, stem, tire pressure, and crank length tools.
Backed by Real Guides
Each calculator links to a detailed fitting guide so you understand the "why" behind your numbers.
Ready to Find Your Perfect Bike Size?
It takes 30 seconds and costs nothing. Start with the general calculator or jump straight to your bike type.