Flight Hours Calculator – Decimal & Logbook Time
To log flight time in decimal hours, divide the minutes by 60: 1 h 45 min = 1.75 h, and one tenth of an hour (0.1) = 6 minutes.
For general informational use. Verify critical aviation calculations and weather with an authoritative source.
Related guides
- Free Ground School Toolkit: time, logbook and study tools for student pilots
- Zulu Time (UTC) in Aviation: why flight times are logged and planned in UTC
Minutes to decimal hours: the logbook chart
Many logbooks and operators record time in tenths of an hour, where each tenth is 6 minutes. The chart rounds to the nearest tenth.
| Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|
| 0–2 | .0 | 33–38 | .6 |
| 3–8 | .1 | 39–44 | .7 |
| 9–14 | .2 | 45–50 | .8 |
| 15–20 | .3 | 51–56 | .9 |
| 21–26 | .4 | 57–60 | 1.0 |
| 27–32 | .5 |
Example: a flight of 1 h 47 min is logged as 1.8. Some operators round differently, for example always down or to the nearest twelfth, so follow your own logbook rules and be consistent.
Decimal hours and minutes without mistakes
Hobbs and tach meters show tenths of an hour, many logbooks use hours and minutes, and airline rosters often use hh:mm. Mixing them is a common source of logbook errors. This tool adds a list of times and shows the total both ways.
How to use it
- Enter one time per line as 1:25, 1.4 or 85m.
- Choose whether decimal results are shown in tenths or hundredths.
- Read the total in hours and minutes and in decimal hours.
- Use the quick table to convert minutes to tenths.
Method and calculation
hh:mm entries are converted to minutes, decimal entries are multiplied by 60, and the total is converted back. Tenths use the common logbook convention: 0.1 h = 6 minutes, so 1:25 rounds to 1.4.
Worked example and practical notes
Entries 1:25, 0.8 and 2:10 total 4 h 23 min, or 4.38 decimal hours (4.4 in tenths).
Quick reference
| 1–3 min | 0.0–0.1 |
|---|---|
| 6 min | 0.1 |
| 12 min | 0.2 |
| 18 min | 0.3 |
| 24 min | 0.4 |
| 30 min | 0.5 |
| 36 min | 0.6 |
| 42 min | 0.7 |
| 48 min | 0.8 |
| 54 min | 0.9 |
Accuracy and practical tips
Pick one method for your logbook and stick to it. Rounding each flight to tenths and then adding can give a slightly different total from adding exact minutes.
Simple time arithmetic. Follow your regulator’s and operator’s logging rules.
Last reviewed: October 2026
Frequently asked questions
How many minutes is 0.1 hours?
Six minutes.
How do I convert 1:45 to decimal?
45 ÷ 60 = 0.75, so 1:45 is 1.75 hours (1.8 in tenths).
Can I mix formats?
Yes. Each line can be hh:mm, decimal hours or minutes followed by m.
Why does my total differ from my logbook?
Rounding each flight separately adds small differences. The tool adds exact minutes first.