Yes. Every tool, game and quiz is open and needs no account, email or subscription. The site is funded by ads, which stay outside the working area of each tool.
Online tools, daily games and quizzes.
Get the task done, play today's puzzle, or find out something about yourself. No signup, straight in your browser.
- Tools
- 389
- Daily games
- 16
- Quizzes
- 55
- Articles
- 60
Today's picks
A fresh selection every day, drawn from the whole catalog.
Tool of the day
BMR Calculator
Estimate basal metabolic rate using the Mifflin-St Jeor equation.
Quiz of the dayConflict Resolution Style Quiz
Discover how you react to conflict with a quiz based on the dual concern model.
Game of the dayGuess the Country
Crack the daily secret country by cross-referencing clues on continent, size, neighbors and direction, in up to 6 tries.
ReadBarcodes and ISBN: the math behind the check digit
EAN-13, UPC-A and ISBN all end in a digit nobody chooses, it is the result of a weighted sum. This guide derives both algorithms by hand, shows how ISBN merged with the barcode in 2007, and proves, with real numbers, which errors each check catches and which slip through.
Catalog by category
389 tools organized by task. All free.
- Runs in your browserMost tools compute everything on your own device.
- No signupNo account, no email, no usage limits.
- No uploadsYour images and files are never sent to any server.
- English and PortugueseThe whole catalog exists in both languages.