Understanding 12:12, 16:8, 18:6, and 20:4 as Tracking Schedules

The numbers in a schedule such as 16:8 are a compact way to describe time. The first number is the number of hours in the fasting window; the second is the number of hours in the eating window. Together, they describe a 24-hour schedule.

Read the notation

Simple Fast offers these schedule labels:

• 12:12 means 12 hours in the fasting window and 12 hours in the eating window.
• 16:8 means 16 hours in the fasting window and 8 hours in the eating window.
• 18:6 means 18 hours in the fasting window and 6 hours in the eating window.
• 20:4 means 20 hours in the fasting window and 4 hours in the eating window.

Each pair adds up to 24 hours. The label describes the duration assigned to each window, not a specific clock time. For instance, 16:8 does not say when your fasting window begins; it only names the duration of the fasting window and the eating window.

These labels describe timing only. They do not tell you which schedule to choose, what to eat, or whether a schedule is appropriate for you. Use the notation here to understand and record a schedule you have already chosen.

Write down the timing you plan to track

Before tracking, note the schedule label and the clock time your fasting window begins. Then note when that window ends and the eating window begins. A simple reference can keep the durations connected to the times in your day:

• Schedule: [your chosen label]
• Fasting window begins: [your chosen time]
• Eating window begins: [your chosen time]

Fill in the times based on your existing plan. If a window crosses midnight, include the date or day with the time so the transition is clear when you look back. If you change the start time, update your note too; otherwise, you may compare the timer with a schedule you no longer mean to track.

Track the windows, then review the record

Simple Fast includes a live fasting and eating-window timer to help you follow the time in your schedule. The app also offers a weekly chart and streaks for reviewing tracking activity over time. Use those views as a record of what you tracked, rather than as a score or an evaluation of your health. Consistent notes about your chosen schedule can also make it easier to understand what a chart is showing.

Simple Fast is a local-only tracker for recording timing, not medical advice. Before changing your eating patterns, consult a healthcare professional who can consider your individual circumstances. The schedule labels and tracking views do not determine which pattern is right for you.

Once you know how to read the numbers, preparing a record is straightforward: write down the label you have already chosen, note its clock-time reference, and use the tracker to follow the timing. If you want a simple way to track fasting and eating windows and review your week, explore Simple Fast.