3:2 Aspect Ratio
3:2 equals exactly 1.5:1, a terminating decimal. For an exact whole-pixel 3:2 frame, the width must be divisible by 3. If W mod 3 = 0, then H = 2W ÷ 3 is a whole number; otherwise the calculated height is fractional and any rounded result is only an approximation.
Why does width divisibility decide exact 3:2 pixels?
Every exact whole-pixel 3:2 frame can be written as 3n × 2n, where n is a positive whole number. The width is therefore always a multiple of 3, and the matching height is always even. This is a stricter test than seeing “1.50” after rounding a calculator display.
For a fixed width, divide by 3 first. A zero remainder means that two thirds of the width is an integer height. A remainder of 1 or 2 means the ideal height lies between pixel rows, so the dimensions must change or be rounded.
Verify a claimed 3:2 size in three steps
- 1Input the width
Use the final exported pixel width, before a viewer rescales it.
- 2Calculate the remainder
Evaluate W mod 3. A remainder of zero is required for an exact integer height.
- 3Check the result
Calculate H = 2W ÷ 3, then confirm W × 2 equals H × 3.
1366-pixel width
1366 mod 3 = 1
1366 × 2 ÷ 3 = 910.666666…
Rounded height = 911
1366 × 2 = 2732
911 × 3 = 2733
The products differ by one, so 1366 × 911 is close to 3:2 but not exact.
Exact and approximate 3:2 pixel sizes
The exact rows below all have a width remainder of zero. The approximate rows expose the fractional ideal height and the effect of rounding to the nearest pixel.
| Pixels | W mod 3 | Decimal ratio | Verdict |
|---|---|---|---|
| 1080 × 720 | 0 | 1.500000 | Exact |
| 1500 × 1000 | 0 | 1.500000 | Exact |
| 1800 × 1200 | 0 | 1.500000 | Exact |
| 1920 × 1280 | 0 | 1.500000 | Exact |
| 3000 × 2000 | 0 | 1.500000 | Exact |
| 6000 × 4000 | 0 | 1.500000 | Exact |
| 1366 × 911 | 1 | 1.499451 | Approximate |
| 1367 × 911 | 2 | 1.500549 | Approximate |
| 1921 × 1281 | 1 | 1.499610 | Approximate |
For 1366 × 911, the relative error is |1366 ÷ 911 − 1.5| ÷ 1.5 × 100 = 0.036590%. A displayed value of 1.50 can hide that difference, while the integer cross-products reveal it immediately.
How do you calculate the missing side?
When width is known, use H = W × 2 ÷ 3. When height is known, use W = H × 3 ÷ 2. Exact whole-pixel output requires the division to finish on an integer.
If a fixed width does not divide by 3, change it to the nearest multiple of 3 when exactness matters. Around 1366 pixels, both 1365 × 910 and 1368 × 912 are exact 3:2 grids; 1366 × 911 is the rounded compromise.
Which print sizes are exact 3:2, and how much gets cropped?
Exact landscape print sizes include 6 × 4, 9 × 6, 12 × 8, 15 × 10, and 18 × 12 inches. Their long side divided by the short side equals exactly 1.5, so a 3:2 image fills them without ratio cropping.
For the mismatched frames below, assume a landscape 3:2 source is enlarged until it fills the print height, then centered. The crop is removed from the long dimension.
| Print frame | 3:2 source at same height | Total long-side crop | Centered crop |
|---|---|---|---|
| 7 × 5 | 7.5 × 5 | 0.5 in | 0.25 in per side |
| 10 × 8 | 12 × 8 | 2 in | 1 in per side |
| 14 × 11 | 16.5 × 11 | 2.5 in | 1.25 in per side |
The crop formulas are source width = print height × 3 ÷ 2 and total crop = source width − print width. A different crop anchor can move the loss to one side, but it cannot remove the ratio mismatch.
Is 3:2 the same as 2:3?
Yes—the same two terms describe opposite orientations. A landscape image measuring 1800 × 1200 is 3:2. Rotating the same pixel counts to 1200 × 1800 produces the portrait notation 2:3. No pixel count or proportion changes; only width and height exchange places.
Use the main aspect ratio calculator when you need to solve a custom missing side, and retain the divisibility and cross-product checks above when the output must be mathematically exact.
3:2 aspect ratio questions
Is 3:2 exactly 1.5?
Yes. Three divided by two terminates at exactly 1.5. This differs from ratios such as 16:9 and 4:3, whose decimal forms repeat.
Which widths produce an exact whole-pixel 3:2 height?
Widths divisible by 3 do. Write the frame as 3n × 2n with one positive whole number n; for n = 500, the result is 1500 × 1000.
Is 1366 × 911 exactly 3:2?
No. Its decimal ratio is about 1.499451, and its cross-products are 2732 and 2733. The one-unit mismatch proves it is approximate.
Will a 3:2 photo fit an 8 × 10 print without cropping?
No. Filling an 10 × 8 landscape frame from a 3:2 source requires a 12 × 8 source area, so 2 inches of the long dimension are removed in total, or 1 inch from each side when centered.
Sources and calculation scope
The 35mm and DSLR context was checked against the Wikipedia image aspect-ratio overview. The 3:2 printing discussion was checked against the photography print-size discussion and Samantha Jean Photography’s visual print guide.
Every remainder, decimal, cross-product, percentage error, and crop amount on this page was calculated from the dimensions printed beside it. The divisibility rule, one-pixel residual proof, and numeric crop ledger are this page’s added precision layer.