A portrait (vertical) frame is taller than it is wide, so its ratio is written with the smaller number first: 9:16, 4:5, 2:3, 3:4. Vertical formats have exploded with phones – Stories, Reels, TikTok and YouTube Shorts are 9:16, while Instagram feed posts look biggest at 4:5 – and they remain the natural shape for portraits, posters, book covers and many print sizes.
Sizing a portrait image works like any aspect ratio: multiply the known width by h/w to get the height, or the known height by w/h to get the width. A 1080 px wide story at 9:16 must be 1920 px tall; a 4:5 post is 1080 × 1350. Print sizes follow the same logic – 4 × 6 in and 8 × 12 in are 2:3, 8 × 10 in is 4:5 and 5 × 7 in is 5:7.
Most photos start life as landscape frames, so the third mode finds the biggest portrait crop that fits inside your original and how much of the picture survives. A 6000 × 4000 camera file cropped to 4:5 keeps 3200 × 4000 – just over half of the frame – so compose with room to spare.
How to use the Portrait Aspect Ratio Calculator
- Portrait ratio
- Ratio width (smaller number)
- Ratio height (larger number)
- I know
- Width
- Height
- Original image width
- Original image height
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Choose the portrait ratio (or enter your own), then the size you know. The other side is the known side times the ratio; for a crop, the calculator keeps the full height if the frame is wide enough and otherwise the full width.
Worked example
A 4:5 post that is 1080 px wide must be 1080 ÷ 0.8 = 1350 px tall. Cropping a 6000 × 4000 landscape photo to 4:5: 6000 ÷ 4000 = 1.5 is wider than 0.8, so keep the full 4000 px height and a width of 4000 × 0.8 = 3200 px – 53.3% of the original.
Portrait sizes
| Ratio | Use | Size |
|---|---|---|
| 9:16 | Stories, Reels, Shorts | 1080 × 1920 |
| 4:5 | Feed posts, 8×10 in | 1080 × 1350 |
| 2:3 | Pinterest, 4×6 in | 1000 × 1500 |
| 3:4 | Phone photos upright | 3000 × 4000 |
| 5:7 | 5×7 in prints | 1500 × 2100 |
Inputs explained
| Field | What to enter |
|---|---|
| Portrait ratio | Choose one: 9:16 – Stories, Reels, TikTok, Shorts, 4:5 – Instagram and Facebook feed, 2:3 – 4×6 in prints, Pinterest, 3:4 – phone photos held upright … |
| Ratio width (smaller number) | A number |
| Ratio height (larger number) | A number |
| I know | Choose one: The width, The height, A landscape image to crop |
| Width | A number |
| Height | A number |
| Original image width | A number |
| Original image height | A number |
What each result means
- Height = [Width]÷[Ratio (width ÷ height)]
- Width = [Height]×[Ratio (width ÷ height)]
- Share of the original kept = [Crop width]×[Crop height]÷([Original image width]×[Original image height])×100
- The same shape in landscape (height ÷ width as w:1) = 1÷[Ratio (width ÷ height)]
Formula
For a portrait ratio w:h (w < h): height = width × h ÷ w · width = height × w ÷ h · crop from W × H: width = H × w ÷ h (if that fits), else height = W × h ÷ w
Worked example
Inputs — Portrait ratio: 4:5 – Instagram and Facebook feed; I know: The width; Width: 1,080.
Results — Ratio (width ÷ height) = 0.8; Height = 1,350; Pixel count (if pixels) = 1.458 MP; The same shape in landscape (height ÷ width as w:1) = 1.25.
Key terms
- Portrait orientation
- A frame taller than it is wide.
- 9:16
- Vertical full-screen phone format, 0.5625:1.
- 4:5
- Vertical format of 0.8:1, used for feed posts and 8 × 10 prints.
Frequently asked questions
What size is a 9:16 Instagram story?
1080 × 1920 px.
What is the best portrait size for Instagram posts?
4:5 at 1080 × 1350 px – the tallest shape the feed shows without cropping.
How do I calculate the width for 2:3?
Multiply the height by 2/3. A 1500 px tall image needs 1000 px width.
Is 3:4 the same as 4:3?
Same shape rotated: 3:4 is portrait (taller), 4:3 is landscape (wider).
What ratio is an 8 × 10 print?
4:5. A 3:2 camera file must be cropped to fit it.
How much of a 3:2 photo survives a 9:16 crop?
37.5%: 6000 × 4000 becomes 2250 × 4000.