Fasting Timer
A simple timer for tracking a fasting window -- pick a duration, start, pause or end it, and see elapsed and remaining time. It keeps running across refreshes, and everything stays in your browser.
Fasting window
Status: Not started · Duration: 16 hours
0% complete
Elapsed
Remaining
Started
Ends
The start time and duration are saved only in this browser (localStorage) so the timer survives a refresh. Nothing is sent to our servers.
Health note: This is a timer only -- it does not recommend fasting and is not a treatment. Fasting may not be appropriate for everyone. If you are pregnant or breastfeeding, have a medical condition (such as diabetes), take medication, have a history of eating disorders, or are under 18, please consult a qualified healthcare professional before fasting. Stop and seek help if you feel unwell.
How this timer works
Choose a preset or custom duration and press Start. The timer records the start time in your browser and calculates elapsed and remaining time from it every second, so it stays accurate even if you close the tab or restart your browser. Pausing stops the clock until you resume; paused time is not counted. When the chosen duration is reached, the page shows a message and -- if you allowed it -- a browser notification. Stop & reset clears the current session.
Is fasting right for me?
Not necessarily. Fasting is not suitable for everyone. People who are pregnant or breastfeeding, have diabetes or other medical conditions, take medication (especially for blood sugar or blood pressure), have a history of eating disorders, are underweight, or are under 18 should speak to a qualified healthcare professional first. This timer does not recommend fasting and is not a treatment.
Does the timer keep running if I close the page?
Yes. The start time is saved in your browser, so the timer shows the correct elapsed and remaining time when you come back -- even after a refresh or browser restart. Notifications only appear while the page is open.
Where is my data stored?
Only in your own browser's local storage on this device: the start time, chosen duration and pause state. Nothing is sent to our servers or included in analytics. Use 'Delete timer data' to remove it.
What durations can I choose?
Presets of 12, 14, 16, 18, 20, 24 and 36 hours, or a custom duration from 1 to 72 hours.
Disclaimer: This tool is for general information and time tracking only and is not medical advice. See our Disclaimer and Terms of Use for more detail.