TimerPlanAbout TimerPlan
TimerPlan is a set of free browser tools for keeping time: countdowns that ring, a stopwatch, clocks for other places, calculators for the arithmetic of hours, and colour panels that turn a screen into a light. Everything runs inside the page, on any modern browser, with nothing to install.
Why it exists
Because a timer is a thing you set and stop watching, and most browser timers are built for the state where you are watching. We measured three ways of building a countdown in a frozen tab: the common ones lost 119 and 147 seconds out of 150, and the method used here lost none. The measurement, the script and the numbers are on the timer accuracy page.
The same reasoning runs through the rest of the site. Alarms are scheduled in advance rather than triggered at zero, so they sound from a background tab. The screen is held awake while anything runs, because a phone that goes dark on the kitchen counter is a timer that failed. Hours appear in both h:mm and decimal, because 7:30 is 7.5 and the other reading costs people money.
How it is built
Plain HTML, CSS and JavaScript, with no framework and no third-party script beyond advertising and the consent tool that legally accompanies it. No tool sends a request while it is working, nothing is uploaded, and nothing is stored on your device — settings travel in the address bar so that a link carries them instead.
Sources are listed on the pages that make factual claims, and where a browser genuinely cannot do something — stop another app’s music, change screen brightness, ring after the tab is closed — the page says so rather than implying otherwise.
Who runs it
TimerPlan is operated by maicrosites, which runs a small family of single-purpose calculator sites. Corrections and requests are welcome: the address is on the contact page, and the fastest way to get something fixed is to say which page and what it got wrong.
A Pro subscription removes the advertising and saves the plans and logs across all of those sites; the counting, the timers and every calculator stay free and unlimited without an account. What is included is on the Free and Pro page.