Road Mountain / MTB Gravel City & hybrid BMX Dirt jump Triathlon / TT Kids Women Men

BIKZER · Sizing guides

Bike size calculator by height and inseam

Start your bike search with your measurements. Choose a riding discipline, enter your height and add your inseam if available. Road frame sizes, MTB labels and children’s wheel sizes describe different things.

Editorial responsibility: Gonzalo Caballero González · Reviewed: 2026-09-18

BIKZER / Sizing guides

Find your reference bike size

Your sizing reference

Enter your measurements to check the chart.

Read our method and limitations →

01 / How to measure

Height

Stand barefoot against a wall and look straight ahead.
Place a level book on your head and mark its lower edge.
Measure from the floor to the mark. Repeat to check consistency.

02 / How to measure

Inseam

Stand barefoot against a wall with your feet slightly apart.
Hold a level book between your legs with firm, comfortable pressure.
Measure from the floor to the top edge. Do not use your trouser inseam.

From a chart to a particular bike

The calculator compares measurements with reference ranges. It shows all matching rows when ranges overlap and flags a conflict when height and inseam disagree. A match is a shortlist, not a guaranteed fit. Look up the exact model and year before buying: a medium or a 54 can have different dimensions in another range.

What to check on a test ride

Check that you can get on and off with control and reach the brakes comfortably. Set the saddle within the seatpost limits, then assess your reach to the handlebar. A stem adjustment can refine a suitable position, but it cannot make every frame suitable. Compare the geometry and adjustment range before deciding.

Choose the right guide

Road and gravel riders should compare stack and reach; mountain bikers also need room to move over the bike. BMX charts use top tube references, while children’s bikes are often grouped by wheel size. The men’s and women’s guides explain proportions and contact points without using gender as a sizing coefficient.

Frequently asked questions

What bike size do I need at 175 cm?

It depends on the discipline and model. In Bikzer’s road chart, 175 cm matches 55–56. Adding inseam can confirm that row or reveal a conflict; do not transfer this number to an MTB.

Is wheel size the same as frame size?

No. A wheel size can be used on several frame sizes. For children, wheel size groups the options but does not replace a fit check.

Why is there no result?

A bike type or valid measurement may be missing, or the measurements may fall outside the chart. We do not invent a size outside the available ranges.

Sources and model checks

Reference size chart

Road

Bikzer reference ranges are not universal size conversions between brands. Overlapping ranges provide several options. Charts always show both units.

Scroll the table sideways to see every column.

Reference size chart · Road
Frame (cm)	Rider height	Reference inseam
47-49	150–158 cm4′ 11.06″–5′ 2.2″	70–73 cm27.56–28.74 in
49-51	158–163 cm5′ 2.2″–5′ 4.17″	73–76 cm28.74–29.92 in
51-53	163–168 cm5′ 4.17″–5′ 6.14″	76–79 cm29.92–31.1 in
53-55	168–173 cm5′ 6.14″–5′ 8.11″	79–82 cm31.1–32.28 in
55-56	173–178 cm5′ 8.11″–5′ 10.08″	82–84 cm32.28–33.07 in
56-58	178–183 cm5′ 10.08″–6′ 0.05″	84–87 cm33.07–34.25 in
58-60	183–188 cm6′ 0.05″–6′ 2.02″	87–90 cm34.25–35.43 in
60-62	188–193 cm6′ 2.02″–6′ 3.98″	90–93 cm35.43–36.61 in
62+	193–210 cm6′ 3.98″–6′ 10.68″	93–110 cm36.61–43.31 in

Mountain / MTB

Bikzer reference ranges are not universal size conversions between brands. Overlapping ranges provide several options. Charts always show both units.

Scroll the table sideways to see every column.

Reference size chart · Mountain / MTB
Frame	Rider height	Reference inseam
XS	145–155 cm4′ 9.09″–5′ 1.02″	69–73 cm27.17–28.74 in
S	155–165 cm5′ 1.02″–5′ 4.96″	74–78 cm29.13–30.71 in
M	165–176 cm5′ 4.96″–5′ 9.29″	79–83 cm31.1–32.68 in
M/L	173–180 cm5′ 8.11″–5′ 10.87″	81–86 cm31.89–33.86 in
L	177–188 cm5′ 9.69″–6′ 2.02″	84–89 cm33.07–35.04 in
XL	188–195 cm6′ 2.02″–6′ 4.77″	89–91 cm35.04–35.83 in
2XL	195–203 cm6′ 4.77″–6′ 7.92″	91–97 cm35.83–38.19 in

BMX

Bikzer reference ranges are not universal size conversions between brands. Overlapping ranges provide several options. Charts always show both units.

Scroll the table sideways to see every column.

Reference size chart · BMX
Top tube (TT) / Wheel (in)	Rider height
TT 18"-20" / Ø 20"	135–155 cm4′ 5.15″–5′ 1.02″
TT 20"-20.25" / Ø 20"	147–162 cm4′ 9.87″–5′ 3.78″
TT 20"-20.5" / Ø 20"	157–173 cm5′ 1.81″–5′ 8.11″
TT 20.25"-21" / Ø 20"	167–183 cm5′ 5.75″–6′ 0.05″
TT 20.75"+ / Ø 20"	180–220 cm5′ 10.87″–7′ 2.61″

City & hybrid

Bikzer reference ranges are not universal size conversions between brands. Overlapping ranges provide several options. Charts always show both units.

Scroll the table sideways to see every column.

Reference size chart · City & hybrid
Frame	Rider height
XS	148–158 cm4′ 10.27″–5′ 2.2″
S	158–168 cm5′ 2.2″–5′ 6.14″
M	168–178 cm5′ 6.14″–5′ 10.08″
L	178–185 cm5′ 10.08″–6′ 0.83″
XL	185–193 cm6′ 0.83″–6′ 3.98″
XXL	193–198 cm6′ 3.98″–6′ 5.95″

Gravel

Bikzer reference ranges are not universal size conversions between brands. Overlapping ranges provide several options. Charts always show both units.

Scroll the table sideways to see every column.

Reference size chart · Gravel
Frame (cm)	Rider height	Reference inseam
43/45	144.7–152.4 cm4′ 8.97″–5′ 0″	67.3–71.2 cm26.5–28.03 in
47/48	152.4–167.6 cm5′ 0″–5′ 5.98″	71.2–75 cm28.03–29.53 in
51	167.6–172.7 cm5′ 5.98″–5′ 7.99″	75–77 cm29.53–30.31 in
54	172.7–177.8 cm5′ 7.99″–5′ 10″	76–82 cm29.92–32.28 in
56	177.8–182.8 cm5′ 10″–5′ 11.97″	81–85 cm31.89–33.46 in
58	182.8–187.9 cm5′ 11.97″–6′ 1.98″	84–87.1 cm33.07–34.29 in
61	187.9–195.5 cm6′ 1.98″–6′ 4.97″	87.1–91.1 cm34.29–35.87 in

Dirt jump

Bikzer reference ranges are not universal size conversions between brands. Overlapping ranges provide several options. Charts always show both units.

Scroll the table sideways to see every column.

Reference size chart · Dirt jump
Wheel and geometry	Rider height
24" · TT ~20"-22"	135–155 cm4′ 5.15″–5′ 1.02″
24" · TT ~20"-22.7"	150–175 cm4′ 11.06″–5′ 8.9″
26" · Reach ~410-415 mm; standover ~710-715 mm	155–170 cm5′ 1.02″–5′ 6.93″
26" · Reach ~425-435 mm; standover ~710-715 mm	170–210 cm5′ 6.93″–6′ 10.68″
26" · TT ~21"-24.5"	160–185 cm5′ 2.99″–6′ 0.83″

Triathlon / TT

Bikzer reference ranges are not universal size conversions between brands. Overlapping ranges provide several options. Charts always show both units.

Scroll the table sideways to see every column.

Reference size chart · Triathlon / TT
Frame (cm)	Rider height	Reference inseam
47-49	150–160 cm4′ 11.06″–5′ 2.99″	65–70 cm25.59–27.56 in
50-52	160–170 cm5′ 2.99″–5′ 6.93″	70–75 cm27.56–29.53 in
53-54	170–175 cm5′ 6.93″–5′ 8.9″	76–80 cm29.92–31.5 in
55-56	176–182 cm5′ 9.29″–5′ 11.65″	80–85 cm31.5–33.46 in
57-59	183–190 cm6′ 0.05″–6′ 2.8″	85–90 cm33.46–35.43 in
60-62	190–205 cm6′ 2.8″–6′ 8.71″	90–110 cm35.43–43.31 in

Kids

Children’s reference based on Trek’s guide, converted to centimetres. Fit also depends on the model, brake reach and minimum saddle height. The 26″ range is capped at 158 cm in this tool.

Scroll the table sideways to see every column.

Reference size chart · Kids
Wheel	Rider height	Reference inseam
12″	91.44–99.06 cm3′ 0″–3′ 3″	38.1–45.72 cm15–18 in
16″	104.14–121.92 cm3′ 5″–4′ 0″	40.64–55.88 cm16–22 in
20″	114.3–137.16 cm3′ 9″–4′ 6″	48.26–63.5 cm19–25 in
24″	124.46–149.86 cm4′ 1″–4′ 11″	58.42–71.12 cm23–28 in
26″	142.24–158 cm4′ 8″–5′ 2.2″	≥ 63.5 cm≥ 25 in