How many megapixels do I lose when cropping?

Cropping reduces megapixels proportionally to the area removed. Cropping to half the width and height keeps only 25% of the pixels (one quarter of the area). A 24MP image cropped in half becomes 6MP. High-resolution cameras (45MP+) give more headroom for cropping.

Is cropping the same as using a longer lens?

Cropping gives the same framing as a longer lens, but with lower resolution and no perspective change. A 50mm crop to 2x gives the framing of 100mm but at quarter the megapixels. It also does not change background compression — only physical distance changes perspective.

How much can I crop and still print?

For a sharp A4 print at the 300 DPI photo standard you need about 8.7 megapixels (3508×2480px). So a 24MP image can be cropped to roughly 33% of its area and still produce a quality A4 print. Drop to 240 DPI (fine for general wall prints viewed at arm’s length) and A4 needs only about 5.5 megapixels (2806×1984px), giving even more cropping headroom. Higher resolution cameras allow more aggressive cropping.

Does crop factor from cropping stack with sensor crop factor?

Effectively yes. If you use a 1.5x APS-C sensor and then crop to half the frame, your effective crop factor is 1.5 x 2 = 3x. A 50mm lens would have an effective FOV of 150mm on full frame.

Crop Calculator — Effective Megapixels After Crop

Calculate the effective megapixels remaining after cropping and the equivalent focal length increase.

Original Width

Full-resolution pixel width of the uncropped image (camera spec sheet or file properties)

Original Height

Full-resolution pixel height of the uncropped image (camera spec sheet or file properties)

Crop Width

Pixel width of your cropped selection (read from the editor crop box)

Crop Height

Pixel height of your cropped selection (read from the editor crop box)

How We Calculate This

Effective Megapixels

Cropped MP = (crop width × crop height) ÷ 1,000,000

Pixels retained scale with the square of the linear crop: halving both width and height keeps only 25% of the megapixels.

Equivalent Crop Factor

Crop factor = original width ÷ crop width

Equivalent FL = base focal length × crop factor

The base focal length defaults to 50mm and is adjustable under Advanced Options. The crop factor is taken from the width axis, so the equivalent focal length is only exact when the crop keeps the original aspect ratio (e.g. 6000×4000 → 3000×2000, both 3:2).

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard optical and photographic formulas. Results may vary with specific equipment.