Everyday
Fuel, unit prices, tips and splitting the bill.
Things you need once, urgently, and then never think about again. It splits cleanly in two: about half of these check that a piece of hardware is working, and the rest sort out a kitchen or a bill.
Test the machine, or measure the kitchen
The hardware checks — microphone, webcam, keyboard, dead pixel, monitor, colour blindness, the on-screen ruler and the tally counter — use the browser’s own device APIs and keep nothing. The microphone test shows a live level meter and records no audio; the webcam test shows you the feed and saves no frame. That is the useful property when you are debugging a call five minutes before it starts and would rather not upload your face to find out the camera works.
The kitchen half converts by ingredient rather than by factor, which is exactly why cups to grams is here and not under Converters: a cup of flour and a cup of honey are the same volume and nothing like the same weight, so it has to be a lookup table. Coffee and cocktail ratios, sourdough hydration, portion sizes and ingredient scaling all work the same way. Tipping and the printable graph paper are here because there was nowhere better. Fuel cost and electricity are Home & workshop.