How to Find the Aspect Ratio of Any Image or Video

Knowing a file's aspect ratio tells you its proportions — whether it is square, widescreen, portrait, or something in between. You need this when uploading to social platforms, ordering prints, embedding in documents, or editing in video software.

The fastest method: enter the image or video's width and height into the free aspect ratio calculator. It gives you the simplified ratio in one click. This guide also shows you how to find the dimensions in the first place if you do not have them handy.

Method 1 — Use the Aspect Ratio Calculator (Fastest)

If you know the image or video's pixel dimensions, this is the fastest path:

1. Open the free aspect ratio calculator
2. Enter the width in the first box (e.g., 1920)
3. Enter the height in the second box (e.g., 1080)
4. The calculator immediately shows the simplified ratio: 16:9

No button to press — it calculates in real time as you type. The result is the mathematically simplified ratio using the greatest common divisor, so 3840×2160 gives you 16:9, not 3840:2160.

You can also work backwards: if you know the ratio you need and one dimension, enter the known dimension, select the target ratio from the presets (1:1, 4:3, 3:2, 16:9, 16:10, 21:9, 9:16), enable the lock toggle, and the other dimension calculates automatically.

Method 2 — Find Dimensions From File Properties

If you have the image file but do not know its dimensions:

On Windows: Right-click the image file → Properties → Details tab. Scroll to "Image" section — you will see "Width" and "Height" in pixels. Enter those into the free aspect ratio calculator.

On Mac: Right-click the image → Get Info. Under "More Info" you will see dimensions. Or open in Preview: Tools → Show Inspector → the first tab shows pixel dimensions.

For videos on Windows: Right-click the video file → Properties → Details → look for "Frame width" and "Frame height."

For videos on Mac: Right-click → Get Info, or open in QuickTime and press Command+I to see the inspector with dimensions.

Once you have the two numbers, enter them into the calculator.

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Method 3 — Find Ratio in Apps and Platforms

Some applications show the ratio or dimensions directly:

• Lightroom: Select photo → click the "i" info overlay (press "i" on keyboard) — shows pixel dimensions. Or in the Library module, the Metadata panel shows dimensions.
• Photoshop: Image → Image Size → shows pixel dimensions. Canvas Size shows the current ratio if you look at width:height.
• Windows Photos app: Open a photo → click the "..." menu → File info → shows dimensions.
• Google Photos: Open a photo → click the "i" info button → shows pixel dimensions.
• YouTube Studio: When you upload a video, the platform shows the detected ratio and resolution in the video details.

Why It Matters — Common Situations Where You Need the Ratio

Social media uploads: Instagram, TikTok, and YouTube have specific aspect ratio requirements. Uploading the wrong ratio results in automatic cropping. Instagram posts support 1:1, 4:5, and 1.91:1 — anything else gets cropped. Knowing your image's ratio before you upload tells you whether it will fit natively or get cut.

Printing: As covered in the printing guide, print sizes have their own ratios. Knowing your file's ratio tells you which print sizes will be a clean match versus which will require cropping or borders.

Video editing: When importing footage into editing software, mismatched aspect ratios result in black bars or distorted footage if your project settings do not match the clip's ratio. Check your footage ratio before starting a project.

Web design: Images embedded in web pages should be sized to their intended display area. If you know both the display area's dimensions and the image's original ratio, you can calculate the exact scaling without stretching or distortion.

Frequently Asked Questions

How do I find the aspect ratio of a photo on my iPhone?

Open the Photos app, select the photo, and tap the info button (the "i" icon). The photo dimensions appear in pixels. Then enter those dimensions into a free aspect ratio calculator — the simplified ratio appears instantly. iPhone cameras shoot in 4:3 by default, or 16:9 if set to video mode.

How can I find the aspect ratio of a video without software?

Right-click the video file on Windows → Properties → Details → look for Frame width and Frame height. On Mac, right-click → Get Info. Enter the two numbers into an aspect ratio calculator to get the simplified ratio. Alternatively, open the video in QuickTime and press Command+I.

Is 1920×1080 always 16:9?

Yes. 1920÷120 = 16, 1080÷120 = 9, so 1920×1080 simplifies to exactly 16:9. This is also called Full HD or 1080p. Any resolution that maintains this ratio (like 3840×2160 or 1280×720) will also simplify to 16:9.