Portrait Aspect Ratio Calculator for Vertical Video & Images

How to Use Our Portrait Aspect Ratio Calculator

To scale your media correctly, you’ll need its original size and one measurement of the new size you’re aiming for. This tool calculates the missing dimension for you.

• Original Width: Enter the width of your source image or video in pixels (px).

• Original Height: Enter the height of your source image or video in pixels (px).

• New Width OR New Height: Enter one of the new dimensions you want to achieve. For instance, if you’re creating an Instagram Story that must be 1080px wide, enter “1080” in the “New Width” field. The calculator will solve for the corresponding height to maintain the original aspect ratio.

Understanding Your Results

The number provided by the calculator is the corresponding dimension (width or height) needed to resize your media without distorting it. This ensures the final image or video is a perfectly scaled version of the original.

A portrait aspect ratio simply means the rectangle’s height is greater than its width. This is the standard for smartphone screens and is dominant on social media platforms like Instagram, TikTok, and for traditional photo prints like 5×7 or 8×10.

The Formula for Perfect Proportions

To prevent your images from looking squashed or stretched, the calculator maintains the original proportional relationship using a standard formula:

When you input a new width, it solves for the new height like this:

This simple math is the key to professional-looking resized content.

Common Portrait Aspect Ratios & Their Uses

Different platforms and mediums are optimized for specific vertical ratios. Knowing which one to use is critical for making your content look its best.

Frequently Asked Questions About Portrait Ratios

What are the best aspect ratios for Instagram in 2025?

Instagram uses several different aspect ratios depending on the placement. For the best results:

• Stories & Reels: Use 9:16 (1080×1920 px). This is non-negotiable for a professional look that fills the screen.

• Feed Posts: You can use square (1:1), but for maximum impact, use 4:5 (1080×1350 px). This vertical format takes up more of the user’s screen as they scroll, grabbing more attention than a square or landscape post.

• Profile Picture: 1:1 (e.g., 320×320 px).

How do I change a landscape image to portrait?

You must crop the landscape image. You cannot simply resize a wide (landscape) image into a tall (portrait) one without extreme distortion. You have to choose which part of the original image to keep.

Concrete Example: Cropping a 16:9 Landscape Photo to a 4:5 Portrait Post

1. Original Image: You have a landscape photo from your TV screen or a video still that is 1920×1080 pixels (16:9).

2. Target Ratio: You want to create a 4:5 portrait post for Instagram.

3. Choose a Dimension: Let’s say you want the final height to be 1350 pixels (a common Instagram dimension).

4. Calculate the New Width: Use the 4:5 ratio. New Width = (Height / 5) * 4. So, (1350 / 5) * 4 = 1080 pixels. Your target resolution is 1080×1350.

5. The Crop: Your original image is only 1080 pixels tall, so you can’t make it 1350px tall without losing quality. Instead, let’s start with the width. Your original is 1920px wide. You need to crop it down to a 4:5 ratio. The best way is to set a fixed crop box in an editing tool (like Photoshop or a free online editor) to a 4:5 ratio. You would then move this box over the most important part of your landscape image (e.g., a person’s face) and crop. The sides of the original image will be discarded.

What’s the difference between portrait and landscape orientation?

It’s a simple distinction:

• Portrait: The image is taller than it is wide. (e.g., 9:16)

• Landscape: The image is wider than it is tall. (e.g., 16:9)

The terms come from art: a “portrait” of a person is typically painted on a vertical canvas, while a “landscape” of scenery is typically painted on a horizontal one.

Why did 9:16 become the standard for phones?

The 9:16 aspect ratio became the standard because it’s the natural inverse of 16:9, which is the universal standard for HDTVs and most video content. When you turn a 16:9 TV on its side, you get a 9:16 rectangle. Since people naturally hold their phones vertically, designing apps and video platforms to fill that 9:16 space created the most immersive, full-screen experience without requiring users to turn their phones.

What is the best portrait ratio for printing photos?

This depends on standard photo paper sizes.

• For 4×6 inch prints, use the 2:3 aspect ratio. A DSLR camera shooting vertically at full-frame produces a 2:3 image that will print perfectly without cropping.

• For 5×7 inch prints, the ratio is 5:7. This is slightly different from most camera sensors, so minor cropping will be necessary.

• For 8×10 inch prints, the ratio is 4:5. This is a great match for Instagram’s preferred vertical feed post size and is a very popular fine art printing size.

How does aspect ratio affect composition in photography?

Aspect ratio is a fundamental part of photographic composition. A taller, narrower ratio like 2:3 or 9:16 forces the viewer’s eye to move up and down, making it excellent for emphasizing height, elegance, and singular subjects (like a person standing or a tall building). A wider ratio encourages the eye to move side-to-side, better for capturing expansive scenes. Choosing your aspect ratio before you shoot can dramatically change the mood and focus of your photograph.

What are “safe zones” for 9:16 video?

When you post a 9:16 video on platforms like TikTok or Instagram Reels, the app overlays buttons, your username, the caption, and other UI elements on top of your video. The “safe zone” is the central area of the screen that is guaranteed not to be covered by these elements. If you are adding important text, logos, or subtitles to your video, you must keep them within this safe zone to ensure they are visible to all users. The exact dimensions vary slightly, but generally, avoid putting critical elements in the top 15% and bottom 25% of the screen.

What does full-frame 3:2 mean?

“Full-frame” refers to a camera sensor that is the same size as a classic 35mm film negative, which is 36mm x 24mm. The aspect ratio of this sensor is 36:24, which simplifies to 3:2. When you hold a full-frame camera vertically to take a portrait, the native aspect ratio of the image is 2:3. This is why the 2:3 ratio is so deeply ingrained in the language of professional photography.

Do I need to worry about Pixel Aspect Ratio (PAR) for social media?

For 99% of users creating content for social media, the answer is no. Modern cameras, phones, and editing software almost exclusively use “square pixels” (a Pixel Aspect Ratio of 1:1). This means the pixel itself is perfectly square. Older digital video formats sometimes used non-square (rectangular) pixels to stretch or squeeze an image into a certain display standard. Unless you’re working with archaic video formats, you can assume your PAR is 1:1 and only focus on the Display Aspect Ratio (DAR), like 9:16.

Can I just rotate a landscape video to make it portrait?

Technically yes, but the result will almost always be unusable. If you rotate a 16:9 landscape video, you will end up with a very narrow 9:16 video with massive black bars on the top and bottom, showing the original video playing sideways in the middle. The proper way to convert landscape video to portrait is to reframe it by cropping into the original frame, keeping the most important part of the action in the center of the new vertical view.

Once you’ve calculated the right dimensions for your portrait image, you might need to ensure its resolution is high enough for printing. You can use our DPI Calculator to check if your image quality is suitable for a physical print. If you need to work with landscape or square formats, our general Aspect Ratio Calculator can help.