Frame Size Calculator

Find the perfect size for picture frames, poster frames, and bike frames. Convert between inches and centimeters and see standard size matches instantly.

Picture & Poster Frame Size Calculator

Set to 0 for no mat. Typical mats are 1–3 in (2.5–7.5 cm) wide.

Approximate width of the frame moulding.

How the picture frame size calculator works

Picture frame sizing can be confusing because different sites talk about “frame size”, “image size”, “opening size” and “outer size” without clearly explaining the difference. This calculator separates each dimension so you know exactly what you are ordering.

Key definitions

  • Artwork size – the actual width and height of your photo, print or poster.
  • Mat opening – the window cut in the mat board. It is usually 2–4 mm smaller than the artwork on each side so the edges are hidden.
  • Frame opening / mat outer size – the size of the glass and backing board. This is what most frame shops call the “frame size”.
  • Outer frame size – the total size including the visible frame moulding around the glass.

Formulas used

1. Mat opening (if mat is used):

Let artwork width = \(W_a\), height = \(H_a\), and mat overlap on each side = \(o\).
Mat opening width \(W_m = W_a - 2o\)
Mat opening height \(H_m = H_a - 2o\)

2. Frame opening / mat outer size:

Let mat border width = \(b\).
Frame opening width \(W_f = W_a + 2b\)
Frame opening height \(H_f = H_a + 2b\)

3. Outer frame size (including moulding):

Let visible frame border = \(c\).
Outer width \(W_o = W_f + 2c\)
Outer height \(H_o = H_f + 2c\)

Standard picture & poster frame sizes

The calculator compares your required frame opening to a list of common standard sizes and shows the closest matches. If you allow rotation, it will also check whether turning the artwork 90° fits a more common frame.

Category Inches Centimeters (approx)
Small photos 4×6, 5×7, 6×8 10×15, 13×18, 15×20
Medium photos 8×10, 8.5×11 20×25, 21×30
Posters 11×14, 12×16, 16×20, 18×24, 24×36 28×36, 30×40, 40×50, 45×60, 61×91
A-series paper A5, A4, A3, A2, A1 14.8×21, 21×29.7, 29.7×42, 42×59.4, 59.4×84.1

How the bike frame size calculator works

Bike manufacturers use different geometry and sizing labels, but inseam-based formulas give a reliable starting point. This tool uses widely accepted rules of thumb and then maps the result to typical S–XL sizes.

Bike sizing formulas

Let inseam length in centimeters be \(L\).

Road bike frame size (cm): \(L \times 0.67\)

Mountain bike frame size (cm): \(L \times 0.59\)

Hybrid / commuter frame size (cm): \(L \times 0.63\)

The calculator rounds to the nearest whole centimeter and also converts to inches (1 in = 2.54 cm).

Typical bike frame size chart (road bikes)

Rider height Frame size (cm) Letter size
150–160 cm 47–50 XS
160–170 cm 51–54 S–M
170–180 cm 55–57 M–L
180–190 cm 58–61 L–XL
190–200 cm 61–64 XL

FAQ

How much bigger should a frame be than the picture?

For a frame without a mat, choose a frame with the same nominal size as your picture (an 8×10 photo goes in an 8×10 frame). The actual opening is usually 1–2 mm smaller so the picture does not fall through. For a frame with a mat, the frame size equals the outer mat size, and the mat opening is cut slightly smaller than the artwork.

What if my artwork is not a standard size?

The calculator will show the closest standard frame sizes and how much extra border you would have. You can either:

  • Order a custom frame to match the exact opening size, or
  • Use a larger standard frame with a custom-cut mat to fit your artwork.

Is this bike frame size guaranteed to fit?

No online calculator can replace a proper bike fit. Use this tool as a starting point, then check the manufacturer’s geometry chart and, if possible, test ride. Riding style, flexibility and personal preference all affect the ideal size.