A simple 30-minute example
Imagine an open event at 09:00 and a close event at 09:30. FoldLog assigns that 30-minute interval to the unfolded state. If you use the screen for five minutes and then leave the phone open with the screen off, the recorded unfolded interval is still 30 minutes.
The example describes the calculation; it is not a measurement from your device. FoldLog does not inspect which apps you use or read their screen activity.
How the duration is calculated
Each saved event has a timestamp and an open or close state. Time until the next event belongs to the previous state. The day view uses these intervals to draw its ring or strip timeline and summarize time spent folded and unfolded.
A phone can remain in one state across a date boundary. Daily totals describe the part of that timeline inside the day, rather than treating every opening as a session entirely contained in one date.
Why a long session can be misleading
A long unfolded interval might mean the phone stayed open on a desk. It can also follow a missing close event. Check the event list and automation setup before treating an unusually long interval as active use.
The app may add a marked recovery event when it is open and the observed device state disagrees with the saved state. This helps correct the timeline, but it does not reconstruct every missed transition or reveal exactly what you did during a gap.
Compare like with like
Use opening count to understand how frequently you open the phone. Use unfolded duration to understand how long it remains open. Consult the system’s Screen Time information when your question is about app use or screen activity.
For a useful comparison, keep recording enabled and compare days with similar coverage. FoldLog’s Patterns view uses sufficiently recorded days and shows insights only when enough data is available. A few incomplete days are a weak basis for a trend.
Look closer at the underlying records
Start with the Today event list and look for the open and close events around the interval you want to understand. If you use Pro, export CSV from Settings to inspect event timestamps, kinds and sources in a spreadsheet.
The CSV contains event records, not an independent screen-time measurement. Keep that distinction when making your own charts, averages or comparisons.