How do I use this calculator?
The basic portion of this calculator allows you to calculate the end time of a 36-hour fast or the start time based on the end time.
Calculator Operations:
- Enter the start time of your fast to calculate the end time (which will be 36 hours later).
- Enter the end time of your fast to calculate the start time (which will be 36 hours earlier).
- Choose the solve mode first and complete its visible date-time fields. Start now uses the actual device clock; a blank progress check-in also uses the current device time.
The calculator uses a fixed 36-hour window and lists 12-, 18-, 24-, and 36-hour calendar checkpoints. Progress is measured at the entered check-in time. The optional schedule label is display-only and does not convert time zones.
Use the calculate button when all known values have been entered and use the reset button when you want to clear the values from the calculator.
Calculate a 36-hour window’s exact start or end time, check elapsed and remaining time, and map 12-, 18-, 24-, and 36-hour calendar milestones.
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36-Hour Fast Formula
The following formula is used to calculate the duration of a 36-hour fast:
Variables:
- D is the duration of the fast in hours
The duration is 36 elapsed hours. Add 129,600,000 milliseconds to the start timestamp for the end, or subtract that amount from the end timestamp for the start. Local clock readings may differ across daylight-saving changes.
What is a 36-Hour Fast?
A 36-hour fast is a period of 36 elapsed hours without calorie intake. For example, 8 PM to 8 AM two calendar days later is 36 hours when no daylight-saving change occurs. This calculator only maps times; its 12-, 18-, 24-, and 36-hour milestones do not predict ketosis or health benefits. Fasting is not suitable for everyone and can cause low blood glucose, dehydration, weakness, or fainting. Consult your clinician before prolonged fasting, especially if you have diabetes or take glucose-lowering medication; do not change medication based on this calculator.
How to Calculate 36-Hour Fast?
The following steps outline how to calculate the duration of a 36-Hour Fast.
- First, determine the starting time of the fast.
- Next, add 36 hours to the starting time.
- Finally, calculate the ending time of the fast.
Example Problem:
Use the following variables as an example problem to test your knowledge.
Starting time of the fast: 8:00 AM
Duration of the fast: 36 hours. Starting at 8:00 AM gives a target of 8:00 PM the next day when no daylight-saving change occurs.
