Image Resolution Calculator

Enter your image's width and height in pixels along with a DPI/PPI value to calculate megapixels, print size (in inches and cm), aspect ratio, and estimated file size. The Image Resolution Calculator helps photographers, designers, and print professionals understand exactly what their image dimensions mean in the real world.

px

Horizontal pixel count of your image

px

Vertical pixel count of your image

dpi

Dots or pixels per inch. 72 dpi = screen, 300 dpi = print quality

Bits per pixel — affects uncompressed file size estimate

Results

Megapixels

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Print Width

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Print Height

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Print Width (cm)

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Print Height (cm)

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Aspect Ratio

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File Size (TIF uncompressed)

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File Size (JPG ~80%)

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Print Dimensions Breakdown (Width vs Height in inches)

Results Table

Frequently Asked Questions

What is the difference between DPI and PPI?

PPI (pixels per inch) refers to the pixel density of a digital image or screen — it describes how many pixels exist in one inch of the image file. DPI (dots per inch) is a print term describing how many ink dots a printer places per inch. In practice, when preparing images for print, you set your image's PPI to match the printer's DPI requirement (typically 300 for quality prints).

How many megapixels do I need for a quality print?

For a standard 4×6 inch photo at 300 DPI, you need about 2.1 megapixels. A high-quality 8×10 print requires roughly 7.2 megapixels. Large format prints (16×20 inches at 300 DPI) need around 28.8 megapixels. Most modern smartphones and DSLRs produce more than enough resolution for common print sizes.

What resolution should I use for web vs. print?

For web and screen display, 72–96 PPI is standard — higher resolution wastes bandwidth without visible benefit on screen. For home or office printing, 150–200 DPI is acceptable. For professional photo prints, 300 DPI is the industry standard. Large format banners and posters viewed from a distance can often use 100–150 DPI.

How is megapixel count calculated?

Megapixels are calculated by multiplying the image width in pixels by the height in pixels, then dividing by one million. For example, a 4000×3000 pixel image is 4000 × 3000 = 12,000,000 pixels, or 12 megapixels.

How do I calculate the print size of my image?

Divide the pixel dimensions by the DPI to get the physical print size. For example, a 3000-pixel wide image at 300 DPI will print at 3000 ÷ 300 = 10 inches wide. Multiply by 2.54 to convert inches to centimetres (10 in × 2.54 = 25.4 cm).

What is a good aspect ratio for photos?

The most common aspect ratios are 3:2 (used by most DSLRs and matching standard 4×6 prints), 4:3 (compact cameras and many mobile devices), and 16:9 (widescreen, ideal for video and modern monitors). The best ratio depends on your intended output — print, social media, or video.

Why is the uncompressed TIF file so much larger than the JPG?

A TIF (TIFF) file stores every pixel's full color data without compression, making it lossless but very large. A JPG file uses lossy compression to discard some visual data, reducing file size by roughly 90% or more at 80% quality with minimal visible quality loss. For archiving and printing, TIF is preferred; for web sharing, JPG is more practical.

Can I increase DPI to improve print quality without a larger original file?

No — simply increasing the DPI setting in software without adding actual pixels is called upsampling or interpolation. It does not add real detail; the software guesses at new pixel values. True resolution improvement requires capturing or scanning the image at a higher pixel count. For best results, always start with the highest resolution original available.

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