Technology & Computing
Image Aspect Ratio, DPI & Megapixel Calculator
Calculate an image's aspect ratio, total megapixels, and physical print size at a given DPI.
Your inputs
Change any value to update the result instantly.
Megapixels
12
Aspect ratio
4 :3
Print width
13.3333 in
Print height
10 in
Higher DPI shrinks the physical print size for the same pixel dimensions but increases sharpness.
Formula and working
Megapixels = (width px × height px) ÷ 1,000,000; Print size (in) = pixels ÷ DPI
- 1
Collect the inputs
Image width (pixels) = 4,000; Image height (pixels) = 3,000; Print resolution (DPI) = 300
- 2
Apply the formula
Megapixels = (width px × height px) ÷ 1,000,000; Print size (in) = pixels ÷ DPI
- 3
Result
Megapixels = 12
Frequently asked questions
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
Report a mistake or request an improvement
Tell us if a formula, unit, explanation, or result needs attention. Your message will include this calculator’s name and page.
Related calculators
Monitor Pixel Density (PPI) & Retina Viewing Distance Calculator
Calculate a display's pixels-per-inch and the minimum viewing distance at which individual pixels become imperceptible.
Refresh Rate Frame Time Render Budget Calculator
Convert a monitor's refresh rate (Hz) into the frame-time render budget in milliseconds, and see multi-frame budgets.
Antenna Gain to EIRP Calculator
Calculate effective isotropic radiated power (EIRP) from transmitter power, cable loss, and antenna gain.
Fresnel Zone Clearance Radius Calculator (60% Rule)
Calculate the first Fresnel zone radius at midpoint and the recommended 60% clearance for a wireless link.
Gaming Mouse eDPI & 360° Turn Distance Calculator
Calculate effective DPI (eDPI) from mouse DPI and in-game sensitivity, and the physical mouse distance for a 360° turn.
Huffman Coding Compression Ratio & Entropy Calculator
Estimate Shannon entropy and Huffman compression ratio for a symbol set versus fixed-length encoding.