You are translating CSS spacing or type
Convert pixels against the project root font size rather than assuming every design uses the browser default. Open PX ↔ REM converter
Quick math
Converters & calculators
Practical design, storage, print, and kitchen calculations with transparent formulas.
Choose a job
What do you need to do?
Convert
PX ↔ REM converter
Convert CSS pixel and rem values using a configurable root font size.
Convert
Aspect ratio calculator
Calculate a missing width or height while preserving an image or video ratio.
Convert
DPI & PPI calculator
Relate pixel dimensions, print dimensions, and resolution for image output.
Convert
Paper size converter
Compare common ISO and North American paper sizes in millimeters, inches, and pixels.
Convert
Data size converter
Convert bytes across decimal KB/MB/GB and binary KiB/MiB/GiB units.
Convert
Recipe scaler
Scale ingredient quantities from an original serving count to a new yield.
Convert
Cooking unit converter
Convert common kitchen volumes and weights between metric and US units.
What this collection covers
The jobs these tools handle
Conversions where guessing wrong costs a reprint or a failed upload. Work out the pixel dimensions behind an aspect ratio, translate px to rem against your root font size, size an image for a target DPI or paper format, read file sizes across KB, MB, GB and their binary equivalents, and rescale a recipe to a different number of servings.
Choose the calculator by the unit behind the requirement
A screen dimension, a print density, and a storage size may all use numbers called size, but they are not interchangeable. Start from the unit the destination actually specifies.
You are sizing an image for print
Relate pixel dimensions, physical inches, and the intended pixel density; do not treat PPI as a promise of printer quality. Open DPI & PPI calculator
You are comparing storage or upload limits
Check whether the source uses decimal KB/MB/GB or binary KiB/MiB/GiB before comparing values. Open Data size converter
Calculate image dimensions for a print layout
Choose the physical page, decide the usable aspect ratio, and calculate pixels from the intended density before resizing the source image.
1. Confirm the physical page
Look up the exact width and height of the chosen paper size and orientation. Open Paper size converter
2. Check the image shape
Compare the page ratio with the source so you know whether cropping or empty margins will be needed. Open Aspect ratio calculator
3. Calculate target pixels
Combine the intended physical dimensions and PPI to get the pixel dimensions for preparation. Open DPI & PPI calculator
Privacy-first by design
Your work stays with you
Selected files and entered text stay private while you use these tools.
Smooth results
Tips for larger files
Very large files can need more memory, especially on a phone. Keep originals, start with a small batch, and close other heavy apps or tabs if a tool feels slow.