Photo Size Lab — Megapixel, Print Size & Image File Size Calculator

Multiply width × height in pixels and divide by 1,000,000. For example, a 6000 × 4000 photo is 24,000,000 pixels = 24 megapixels. The Megapixels tab above does it instantly.

Divide pixels by DPI: 6000 ÷ 300 = 20 inches, 4000 ÷ 300 = 13.3 inches. So a 24 MP (6000×4000) photo prints at 20 × 13.3 inches at 300 DPI — plenty for a 16 × 20 inch frame.

DPI (dots per inch) is a printer setting: how many ink dots land per inch of paper. PPI (pixels per inch) describes image density on a screen. For printing they play the same practical role — pixels per inch on paper. A '300 DPI print' means the printer maps 300 image pixels onto each inch.

Not always. 300 DPI is the standard for prints viewed up close (up to ~12 inches wide). Larger prints are viewed from farther away, so you can drop to 240 DPI up to 24 inches, 150 DPI for posters, and 100 DPI or less for billboards — the viewing distance hides the lower resolution.

Divide cm by 2.54 to get inches, then multiply by DPI. Example: a 20 × 30 cm print at 300 DPI = 7.87 × 11.81 inches × 300 = 2362 × 3543 pixels (8.4 MP). The Print Size tab accepts cm directly.

At 300 DPI: 8 × 300 = 2400 by 10 × 300 = 3000 pixels, i.e. 7.2 megapixels. Almost any modern camera or phone exceeds this, so an 8×10 print is easy.

Roughly 7 MB at quality 90 (≈10:1 compression) — but it is only an estimate. Real 24 MP JPEGs range from ~4 MB (simple scene, high compression) to ~15 MB (busy, noisy scene at high quality). Use the File Size tab with your quality setting.

Quality 90 compresses about 10:1, quality 80 about 15:1 — so the same 24 MP photo is roughly 7.2 MB at q90 and 4.8 MB at q80. Visually, q80–90 is nearly identical for most photos; the difference only shows on close inspection or heavy editing.

HEIC is typically about 50% smaller than JPEG at the same visual quality — a 24 MP photo that is 7.2 MB as JPEG q90 is roughly 3.6 MB as HEIC. That is why phones default to HEIC. The File Size tab compares both side by side.

Much bigger. A 24 MP camera's 14-bit RAW is 42 MB of sensor data, versus ~7 MB for the same shot as JPEG q90 — about 6× larger. The trade-off is editing latitude: RAW keeps far more highlight and shadow detail.

Divide card capacity by file size: 64 GB ÷ 7.2 MB ≈ 8,888 JPEGs (24 MP, q90), or 64,000 ÷ 42 ≈ 1,524 RAW files. The Storage tab computes this for any card size and file size.

Upload 1080 × 1350 pixels (4:5 portrait) — it is the tallest format allowed in the feed and gets the most screen space. Square posts are 1080 × 1080; Stories and Reels are 1080 × 1920. Instagram compresses everything to these widths anyway.

1280 × 720 pixels (16:9), under the 2 MB upload limit. Channel art is 2560 × 1440, but keep important content inside the 1546 × 423 safe area so it is visible on every device.

3:2 — the classic DSLR/mirrorless ratio (6000 and 4000 share a greatest common divisor of 2000). The ratio is shown as information only here; for resizing or cropping calculations use our aspect ratio calculator.

No. Photo Size Lab runs 100% in your browser — you only type numbers, and nothing (not even those) is sent anywhere. There are no accounts, no uploads, and no tracking.

JPEG compression is content-dependent: a flat blue sky compresses far better than a detailed, noisy crowd scene. Estimates in this tool use standard quality-to-ratio anchors (q90 ≈ 10:1, q80 ≈ 15:1, q50 ≈ 30:1); real files commonly land within ±2× of the estimate.