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Crop Zoom Resolution Calculator

Resolution left after cropping in to simulate a longer lens.

Original width

Original height

Crop zoom factor

Lens focal length

How it works

Cropping by a factor z divides both width and height by z, so the pixel count falls by z². The field of view matches a lens z times longer. This is a free way to reach farther when you cannot change lenses, but high-ISO noise and softness become more visible. Keep the crop above the resolution your print or screen needs. Example: A 2× crop of a 6000 × 4000 px photo leaves 3000 × 2000 px, or 6 MP, and frames like a 100 mm lens.

FAQ

Is this calculator free?

Yes. No signup is needed and nothing you enter is stored.

Is the result exact?

Results are rounded for display. For financial, medical, or legal decisions, confirm with a professional.

Do my numbers leave my device?

No. The calculation runs in your browser.