Image, photo and design calculators

Find the aspect ratio of any width and height, or resize to a new width or height without stretching. Covers 16:9, 4:3, 1:1, 4:5 and 9:16, with pixel tables.

Work out a video's bitrate from its file size and length, or the video bitrate to set for a target file size with the audio subtracted. In Mbps and kbps.

Set up a Procreate or Photoshop canvas in pixels for any print size and DPI, add bleed, or find the pixels a gallery-wrapped canvas print needs.

Convert cm or mm to pixels at 72, 96, 150, 200, 300 or 600 DPI. 3.5 × 4.5 cm is 413 × 531 px at 300 DPI, A4 is 2480 × 3508 px and 1 cm is 38 px in CSS.

Check the contrast ratio of any text and background hex pair against WCAG 2.1: 4.5:1 for AA, 7:1 for AAA, 3:1 for large text and UI parts. Formula shown.

Pick any colour from an image or screenshot and copy its HEX, RGB or HSL code, plus the image's main colour palette. Free, private, works in your browser.

Get the crop factor of any camera sensor, the full-frame equivalent focal length and aperture of your lens, and the megapixels left after cropping.

Enter a lens, aperture and focus distance to get the near and far limits of sharpness, the total depth of field and the hyperfocal distance, plus a table.

Find the DPI of an image at a print size, the print size at 300 DPI, or your mouse eDPI and the matching sensitivity for a new DPI. Explains DPI vs PPI.

Work out the exposure value (EV) of any aperture, shutter speed and ISO, swap one setting for an equivalent one, and get the shutter time behind an ND filter.

Work out the field of view of any camera, lens and sensor, the focal length for a wanted angle, game FOV for any aspect ratio, and telescope true field.

Find the camera lens that fits a subject in the frame, solve the thin lens equation, combine two lenses or close-up filters, and work out a zoom ratio.

Work out heading font sizes from a base size and ratio, build a fluid CSS clamp() font size between two screen widths, or convert points to pixels and inches.

Convert seconds to frames and frames to seconds at any fps, including 23.976 and 29.97, turn timecode into frame numbers, and work out slow motion.

Golden ratio calculator for design, layouts, type and woodwork: enter the longer or shorter side, or split a total into 61.8% and 38.2%, in px, mm or inches.

Convert hex to RGB: paste a hex code like #4A90E2 and get rgb(74, 144, 226), each channel, CSS rgba() and HSL. Reads 3-, 6- and 8-digit codes with alpha.

Calculate an image's uncompressed file size from its width, height and colour depth, estimate the JPEG or PNG size, and scale pixel dimensions by a percentage.

Extract text from an image, screenshot or photo for free. Copy it or download a .txt file. OCR runs in your browser, so the picture is never uploaded.

Work out how many pixels an inch needs at 72, 96, 150, 300 or 600 DPI. 2 × 2 inches is 600 × 600 px at 300 DPI; 8.5 × 11 in is 2550 × 3300 px.

Turn a width and height into megapixels, or a megapixel count and aspect ratio into width and height, and see the largest print at 300, 240 and 150 PPI.

See how many photos fit in 64 GB, 128 GB, 1 TB or your free cloud plan at a typical JPEG, HEIC or RAW size, or how much storage a number of photos needs.

Convert pixels to centimetres and millimetres at 72, 96, 150, 300 or 600 PPI. 100 px is 2.646 cm on a 96 PPI screen; 1080 px is 28.575 cm, or 9.144 cm in print.

Convert pixels to inches at 72, 96, 150, 300 or 600 DPI, for one length or a full width × height. 1920 × 1080 px prints at 6.4 × 3.6 in at 300 DPI.

Find the pixels a poster needs at 100, 150 or 300 PPI, from 11×17 to 36×48 in and A3 to A0, and how far away people must stand before the pixels disappear.

Work out the pixels per inch of any screen from its resolution and diagonal, plus dot pitch and total pixels. Tables for 1080p, 1440p and 4K monitors and TVs.

See how large a photo can print at 300, 200 or 150 PPI in inches and cm, which standard prints (4×6 to 20×30, A4, A3) it fills, and the pixels each needs.

Convert px to em and em to px using the parent element's font size, not the root. 24px in a 16px parent is 1.5em. Shows how nested em values compound.

Convert px to rem and rem to px with the root font size you use. 24px is 1.5rem at the 16px browser default. Formula, conversion table and the 62.5% trick.

Convert RGB to hex: type red, green and blue (0–255) to get the #RRGGBB color code, 3-digit shorthand, HSL and CSS rgb(), with the formula and a color chart.

Turn a screen diagonal and aspect ratio into width, height and area in inches and cm, or the reverse. Compare two TV or monitor sizes by area.

Plan a time-lapse: enter the event length, interval and frame rate to get the number of photos, clip length and card space, or find the interval for a clip.

Find how far to sit from a 32 to 98 inch TV, or what size TV suits your sofa distance, using 30° and 40° viewing angles and 4K and 1080p pixel limits.

Estimate a video's file size from its bitrate and length, in MB or GB, or see how many hours of footage fit on a 64 GB, 128 GB or 1 TB card. 1080p and 4K.