Bike Size Charts
Trail, XC, and hardtail sizing

Mountain Bike Size Chart

Find a starting mountain bike frame size from height and inseam. Wheel size is a separate choice from S/M/L.

Find my starting sizeOpen the size calculator
Frame sizes
XS–XXL · 6 sizes
Rider height
4'11"–6'8"
Height (cm)
150–204 cm
Inseam check
67–98 cm

Mountain size finder

Find my MTB size

Letters first, traditional inch frame second. Wheel size is a separate choice.

  • Height picks the size from the published chart.
  • Inseam confirms standover and the size to compare.
  • The chart below marks the matching size.
ft
in

Recommended. Helps confirm clearance, not wheel size.

Mountain bike size chart by height

Letter sizes with typical traditional frame measurements. Wheel size is not a frame size.

Size

XS

Traditional frame

13–14"

Height: 150–160 cm

Inseam: 67–72 cm

Size

S

Traditional frame

15–16"

Height: 158–169 cm

Inseam: 71–77 cm

Size

M

Traditional frame

17–18"

Height: 167–178 cm

Inseam: 76–82 cm

Size

L

Traditional frame

19–20"

Height: 176–188 cm

Inseam: 81–87 cm

Size

XL

Traditional frame

21–22"

Height: 186–198 cm

Inseam: 86–93 cm

Size

XXL

Traditional frame

23"+

Height: 193–204 cm

Inseam: 91–98 cm

Start with height. If two sizes overlap, use cycling inseam to choose.How to measure

Riding style

XC vs trail vs enduro sizing

XC

Shorter travel and often longer reach on modern race bikes. Do not copy an old hardtail size.

Trail

Reach and standover matter more than S/M/L. Size down if you want quicker handling.

Enduro

Longer travel bikes often fit larger. Confirm published reach, not the letter alone.

Frame vs wheels

MTB wheel size is different from frame size

27.5, 29, and mixed or mullet setups change handling. They are not a substitute for XS through XXL. Height does not map to 29 by itself.

Mountain kit

Helmet, a light, a lock, a bottle, and a pant-leg strap. Frame size and wheel size are separate choices.

See more in Shop
Giro Register II MIPS adult bike helmet

Giro

Register II MIPS

Everyday adult helmet with MIPS and a simple dial fit.

Universal Adult, 54–61 cm

View on Amazon

Price and availability on Amazon

NiteRider Swift 300 USB bike headlight

NiteRider

Swift 300

Compact USB headlight for commuting and dusk rides.

Handlebar mount, 300 lumens

View on Amazon

Price and availability on Amazon

Kryptonite Evolution Mini-7 U-lock with cable

Kryptonite

Evolution Mini-7 with 4′ cable

Hardened U-lock plus a cable for wheels or a locked-together pair.

Fits most road, gravel, and hybrid frames

View on Amazon

Price and availability on Amazon

CamelBak Podium Chill 21 ounce bike bottle

CamelBak

Podium Chill 21 oz

Insulated squeeze bottle for everyday rides.

Fits a standard ~73 mm cage

View on Amazon

Price and availability on Amazon

Green Guru narrow pant-leg strap

Green Guru

Narrow pant-leg strap

Upcycled inner-tube strap that keeps a pant leg off the chain.

Adjustable hook-and-loop, about 16 in long

View on Amazon

Price and availability on Amazon

As an Amazon Associate we earn from qualifying purchases. Affiliate disclosure.

Mountain sizing notes

Match the reach, not the letter.

MTB letters change between seasons and riding families. Reach and standover hold up better than the label.

Take your own measurements4 checks

  1. Letters replaced inches

    Modern mountain bikes are sized XS to XXL. Older bikes used 15–19 inch seat-tube labels, and those numbers still turn up on used listings next to the letter sizes.

    Check: On a pre-2015 bike, match reach rather than the inch label.

  2. Frame size is not wheel size

    27.5, 29, and mixed or mullet setups are wheel choices. They change handling and standover slightly, but the frame size decides whether the bike fits you.

    Check: Choose the frame size first, then the wheel size for your terrain.

  3. Reach matters more than standover

    Sloping top tubes make standover easy on almost every size. A frame can clear your inseam and still be too long, especially on a current trail bike with a long front center.

    Check: Compare published reach on the sizes you are considering.

  4. Between two mountain bike sizes

    Smaller usually means quicker steering and more room to move; larger means more stability at speed. XC, trail, and enduro shift where that balance sits, so the letter alone cannot settle it.

    Check: Size down for tight trails; size up only when the reach still feels short.

Related guides

Choose the right chart for your bike

Once you have a starting size, compare the chart for your bike type or exact model.

Trek mountain bike size chart

Compare Trek MTB sizes and geometry.

Read

Giant mountain bike size chart

Compare Giant MTB sizes and geometry.

Read

Specialized mountain bike size chart

Compare Specialized MTB sizes and geometry.

Read

How to choose a bike size

Start with height and inseam, then use fit and handling to choose between sizes.

Read

Questions

FAQ

Quick answers to common bike-sizing questions.

What size mountain bike frame do I need?

Match height to XS through XXL, then confirm inseam and reach. Traditional inch labels such as 17-18 inch usually sit near M.

Should I size up or down on a mountain bike?

Size down for maneuverability and size up for stability, but only after standover and reach both work.

Is MTB size based on height or inseam?

Height sets the first range. Inseam confirms standover, and reach determines how stretched the cockpit feels.

Does my height tell me to ride 27.5 or 29?

No. Wheel size is separate from frame size. Many sizes are offered in more than one wheel option.

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