# Portrait Aspect Ratio Calculator

URL: https://speedycalculator.com/calculators/other/portrait-aspect-ratio/
Last updated: 2026-10-30

> The portrait aspect ratio calculator sizes vertical images and videos – 9:16 stories and reels, 4:5 feed posts, 2:3 and 3:4 prints – giving the matching height or width and the largest portrait crop you can take from a landscape photo.

## Inputs

- Portrait ratio
- Ratio width (smaller number)
- Ratio height (larger number)
- I know
- Width
- Height
- Original image width
- Original image height

## Results

- Ratio (width ÷ height)
- Height
- Width
- Crop width
- Crop height
- Share of the original kept
- Pixel count (if pixels)
- The same shape in landscape (height ÷ width as w:1)

## 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
```

## Explanation

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

RatioUseSize9:16Stories, Reels, Shorts1080 × 19204:5Feed posts, 8×10 in1080 × 13502:3Pinterest, 4×6 in1000 × 15003:4Phone photos upright3000 × 40005:75×7 in prints1500 × 2100

### Inputs explained

FieldWhat to enterPortrait ratioChoose 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 numberRatio height (larger number)A numberI knowChoose one: The width, The height, A landscape image to cropWidthA numberHeightA numberOriginal image widthA numberOriginal image heightA 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)]

## 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.

## FAQ

**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.


## Sources

- [Wikipedia – Aspect ratio (image)](https://en.wikipedia.org/wiki/Aspect_ratio_(image))
- [Instagram Help Centre – Photo resolution](https://help.instagram.com/1631821640426723)
- [Wikipedia – Photo print sizes](https://en.wikipedia.org/wiki/Photo_print_sizes)