How to use the fasting timer
Three steps, and none of them needs an account. Pick a duration from the quick-start buttons or enter a custom one, press start, and leave it. The countdown runs from that moment and the page shows the exact time your fast ends alongside the time remaining.
If you already ate hours ago
This is the normal case rather than the exception. Most people remember the timer some way into the fast, so the start time is editable and accepts a time earlier than now. Set it to when your last meal actually ended and every number on screen recalculates from there. You can also come at it the other way and run the fasting time calculator first, then hand the result straight to the timer.
While the fast runs
Close the tab, close the browser, restart the machine. The fast is stored as timestamps rather than as a running process, so reopening the page recomputes elapsed time from the real clock and shows the correct figure. Nothing runs in the background and nothing drains a battery.
When it ends, and when it does not
Reaching the target flips the display to your eating window and counts down to when the next fast begins, so the follow-up question has an answer without you asking it. If you break the fast early, press end and the actual duration is recorded beside the target with no commentary attached. A fast you stopped at fourteen hours is stored as fourteen hours, because a history made of real numbers is the only kind worth keeping.
Built around how people actually fast
The most common timer complaint isn't about features: it's "I forgot to press start." Rigid timers turn that small slip into corrupted data or an abandoned day. This timer treats corrections as normal: edit the start time and it recalculates; break your fast early and it records the actual duration beside the target, neutrally; cancel a fast that isn't happening without ceremony. When a fast completes, the timer doesn't stop being useful: it flips to your eating window and counts down to the next fast, so the question "when does my window close?" always has a live answer on screen.
Under the hood it works the only way a reliable web timer can: your fast is stored as absolute timestamps on your device, and every displayed number is recomputed from the real clock. Close the tab for nine hours, reopen it, and the elapsed time is exactly right: no background process required, no drift, no battery cost.
Timer, clock, counter, tracker: one tool
People search for this tool under many names (fasting clock, fasting countdown, fasting counter, intermittent fasting tracker), and the differences matter less than apps pretend. A countdown tells you what remains; a clock places your windows in the day; a tracker remembers what actually happened. This page does all three: the live countdown with percent complete and exact end time, the schedule boundaries from whichever calculator you started from, and automatic local history with averages, medians, your longest fast, and target completion, plus optional streaks if you switch on Motivation Mode. What it deliberately isn't: a calorie counter, a recipe feed, a social network, or a subscription. Reddit threads about fasting apps repeat one sentence in different words, "I just need the timer", and that sentence is this page's entire specification.
Start from a calculation, not a guess
The timer is connected to every calculator on this site: run "When can I eat?", a protocol calculator, or the schedule planner, press "Start fast" on the result, and the timer picks up the exact schedule, including a start time earlier than now if your last meal already happened. Quick-start buttons above cover the common protocols (12:12 through OMAD) and any custom duration up to 7 days for extended fasts. Whichever way you start, the same tested calculation engine defines the boundaries, so the timer never disagrees with the calculators.
Browser timer or a fasting app?
Worth answering honestly, including the parts where an installed app genuinely wins. Most pages comparing these two are published by somebody who wants you to download something.
| This browser timer | A typical fasting app | |
|---|---|---|
| Getting started | Open the page and press start | Install, then usually create an account |
| Cost | Free, with no paid tier at all | Often free to start, with features behind a subscription |
| Where your data sits | In your browser, on your device | Usually on the company servers |
| Push notifications | No. Calendar export covers reminders instead | Yes, and this is the real advantage |
| Lock screen and widgets | No | Yes |
| Works across your devices | Each browser keeps its own history | Syncs, because there is an account behind it |
| Fasting stage labels | Deliberately not shown | Commonly shown, usually without evidence |
Two rows there favour the app and we are not going to pretend otherwise. If a push notification at hour sixteen is the feature that makes you keep a schedule, install something. The same applies to syncing between a phone and a laptop, which needs an account by definition, and an account is the thing this site does not have.
What you get in exchange is that nothing is gated. There is no version of this page where the countdown you used last week moves behind a paywall, because there is no paid tier to move it into. If reminders matter to you, the calendar export turns your fast end and window close into ordinary calendar events with ordinary alerts, which uses a system you already trust rather than asking for a new one.
How it behaves on your device
The usual objection to a timer that lives in a tab is that a tab is a fragile place to keep something for sixteen hours. It would be, if the timer counted. It does not.
Closing the tab, and restarting
Your fast is saved as a start timestamp rather than as a running counter, so every number on screen is recomputed from your device clock each time the page loads. Close the tab for nine hours and reopen it and the elapsed figure is exact. The same holds after closing the browser entirely or restarting the machine.
Phones, and switching between devices
It works the same on a phone browser, and adding the page to your home screen gives you something close to an app icon without an install. What it will not do is follow you between devices: a fast started on your laptop lives in your laptop's browser, because syncing would require an account and a server. That is a deliberate trade rather than a missing feature.
Private windows and clearing site data
Both will lose your history, and it is better to know that now than to discover it later. A private or incognito window discards everything when you close it, and clearing site data removes stored fasts along with everything else. If your history matters to you, export it from the history page as CSV or JSON occasionally. That file is yours and opens in any spreadsheet.
A browser extension that aggressively clears storage can have the same effect. If you run one and want to keep a fasting record, the export is the reliable route rather than trusting the browser to hold it. This is the honest cost of a tool with no account behind it, and it seemed better to name it here than to let you find out in month three.
Why we don't show "fat-burning stages"
Many fasting timers decorate the countdown with stage labels: ketosis at hour 12, autophagy at hour 16, each with an icon. It reads as science and tests as fiction: human research does not support assigning those transitions to precise clock hours, and the true timing varies with your previous meals, glycogen, activity, and individual metabolism. We'd rather show you three numbers that are actually true (elapsed, remaining, percent of target) than five that are decorative. If you want to read about what research does and doesn't establish on fasting physiology, our editorial standards explain how we handle the evidence. Your timer should count time; it shouldn't tell stories.