Inseam is often more useful for estimating frame and saddle height, while height helps define the commercial size range. Using both is more reliable.

Does the calculator replace a bike fitting?

No. It is useful before buying or for a first setup. Pain, asymmetry and precise performance positioning require a real test or a bike fitter.

Quick bike fit, no account

Calculate bike size, frame and first setup numbers

Enter height and inseam, get frame size, frame range and saddle height — indicative estimate, no account.

Road cyclist illustration for the BikeSize bike size guide

Measure inseam first

Place a book between your legs, press it like a saddle and measure from the floor to the upper edge. This number matters more than height for frame choice.

Always compare geometry

Stack, reach and standover change from brand to brand. Commercial size is useful, but the model geometry decides the real position.

If you are between two sizes

The smaller size tends to be more agile and easier to tune with stem and cockpit setup. The larger size tends to be more stable but harder to shorten.

It is not a bike fitting

This tool helps before buying. If you have pain, asymmetry or performance goals, use a test ride or a bike fitter.

Size

—

Enter height and press Calculate to see size, frame and saddle height.

Frame

—

Height

—

Inseam

—

Saddle

—

Step 2: fine-tune your bike

Use these as a starting point, then adjust on the real bike.

Saddle height

inseam x 0.883

Inseam

Enter your inseam.

Tire pressure

starting estimate

Weight

Tire

Surface

Bike type

Front

—

Rear

—

Smaller or larger size?

quick choice

Smaller size

Larger size

Choose the riding style that matters most.

Geometry to check before buying

Reach

Horizontal length — longer or shorter position.

Stack

Front height — more upright or more aggressive.

Standover

Clearance above the top tube. Critical on MTB and gravel.

Effective top tube

Helps estimate how stretched you will feel. Two bikes with the same size can have very different top tubes.

Reference chart

Road bike sizes
Size	Height (cm)	Inseam (cm)	Frame (cm)
XS	140–152	68–73	46–49
S	153–162	73–77	49–52
M	163–170	77–82	52–55
M/L	171–178	82–86	55–58
L	179–186	86–90	58–61
XL	187–195	90–93	61–63
XXL	196+	93+	63+

MTB sizes
Size	Height (cm)	Inseam (cm)	Frame (cm)	Frame (")
XS	140–154	66–72	33–37	13–14.5"
S	155–164	72–76	37–41	14.5–16"
M	165–174	76–81	41–44	16–17.5"
L	175–184	81–86	44–48	17.5–19"
XL	185–194	86–91	48–52	19–20.5"
XXL	195+	91+	52+	20.5"+

Trekking bike sizes
Size	Height (cm)	Inseam (cm)	Frame (cm)
XS	140–152	68–72	42–45
S	153–162	72–76	46–49
M	163–172	76–81	50–53
L	173–182	81–86	54–57
XL	183–192	86–90	58–61
XXL	193+	90+	62+

Gravel bike sizes
Size	Height (cm)	Inseam (cm)	Frame (cm)
XS	145-157	68-74	46-49
S	158-167	74-79	49-52
M	168-177	79-84	52-55
L	178-187	84-89	55-58
XL	188-197	89-94	58-61
XXL	198+	94+	61+

E-bike sizes
Size	Height (cm)	Inseam (cm)	Frame (cm)
XS	145-157	68-74	43-46
S	158-167	74-79	46-49
M	168-177	79-84	49-53
L	178-187	84-89	53-57
XL	188-197	89-94	57-61
XXL	198+	94+	61+

Kids bike sizes
Wheel/size	Height (cm)	Inseam (cm)	Notes
12"	90-104	34-43	first bike
14"	100-114	40-48	14" wheel
16"	110-124	45-53	16" wheel
20"	120-139	52-62	20" wheel
24"	135-154	60-70	24" wheel
26"/XS	150-164	68-76	26" or XS adult

Frequently asked questions

Height or inseam?

Inseam is better for frame and saddle estimation. Height gives the general commercial size range.

What if I am between two sizes?

Smaller usually feels more agile, larger usually feels more stretched and stable. A real test ride still wins.

Does this work for every brand?

No. Geometry changes by brand and model. Compare the result with the official size chart.