Night flight time calculator.
Work out how much of a sector counts as night, from the two aerodromes, the UTC date and the block times, on the civil-twilight definition that SERA and Part-FCL are written around.
The two ends of the sector
Pick the aerodromes from the list, or type coordinates for a strip that is not in it. Night is computed along the great circle between the two positions, so a westbound sector that chases the sunset gets the right answer.
Date and times
The date is the UTC date of the off-block time. An on-block time earlier than the off-block time is read as the next UTC day.
Every time on this page is UTC. Enter UTC and read UTC. Local time, summer time and a timezone offset are all ways to get an answer that is an hour or two out, and a night entry that is an hour out is a night entry that is wrong.
Choose a departure and an arrival, then enter the UTC date, off-block time and on-block time to get the night time.
In the EASA ATPL exam
Night is an Air Law definition first. The examiner tests whether you know it is bounded by civil twilight rather than by sunset and sunrise, and that a Member State may prescribe something else. General Navigation then asks the same thing as a working problem, because when an aircraft is in night depends on where it is as much as on what the clock says.
That pairing is why the terminator matters. A westbound sector stays in twilight longer than the aerodrome it left, and a sector at high latitude in June can log no night at all, which is a navigation answer reached from a legal definition.
Exam-style example
An evening sector from Manchester to Palma de Mallorca on 15 October 2026, run through this calculator. Off blocks 17:30 UTC, airborne 17:45 UTC, on the ground 20:05 UTC, on blocks 20:15 UTC.
- Inputs: EGCC Manchester at 53.3494 north, 2.2795 west, to LEPA Palma de Mallorca at 39.5517 north, 2.7388 east, on 15 October 2026, with those four UTC times.
- Block time is 17:30 to 20:15, which is 2:45.
- Evening civil twilight ends at 17:48 UTC at Manchester and at 17:37 UTC at Palma, so the sector goes off blocks in daylight and flies into darkness.
- Walking the great circle a minute at a time finds one day-to-night crossing, at 17:48 UTC, three minutes after take-off.
- Night therefore runs from 17:48 UTC to on blocks at 20:15 UTC, in one unbroken period.
Night 2:27, day 0:18, block 2:45. Sunset at Manchester was 17:13 UTC, before the aircraft moved, so logging night from sunset would have claimed the whole 2:45 and 18 minutes that are not there.
Common trap: The two ends disagree, and the answer belongs to neither of them. Twilight ends 11 minutes earlier at Palma than at Manchester that evening, and the aircraft spends the sector between the two. Reading the departure aerodrome's time off a table and applying it to the whole flight is the error the moving-position calculation removes.
How night flight time is computed
The definition, the formula, a worked example and how it shows up in the ATPL exams.
How night flight time is computed
The definition, the formula, a worked example and how it shows up in the ATPL exams.The EASA night definition, quoted
Regulation (EU) No 923/2012 (SERA), Annex, definition (97): "'night' means the hours between the end of evening civil twilight and the beginning of morning civil twilight. Civil twilight ends in the evening when the centre of the sun's disc is 6 degrees below the horizon and begins in the morning when the centre of the sun's disc is 6 degrees below the horizon".
Regulation (EU) No 1178/2011 Annex I (Part-FCL), point FCL.010: "'Night' means the period between the end of evening civil twilight and the beginning of morning civil twilight or such other period between sunset and sunrise as may be prescribed by the appropriate authority, as defined by the Member State."
SERA is pure civil twilight. Part-FCL keeps that wording and then opens a door: a Member State may prescribe a different period between sunset and sunrise, and where one has, that prescribed period is what governs the night hours you claim towards a licence, a rating or a currency requirement. Find out what your own authority has prescribed before you log a figure from any calculator, this one included. What this tool computes is the civil-twilight definition.
Why sunset plus 30 minutes does not work
The rule of thumb assumes the gap between sunset and the end of civil twilight is a constant. The sun sets steeply near the equator and shallowly near the poles, and the same place changes through the year, so the gap runs from about 20 minutes near the equator to over an hour in northern Europe in summer.
Above roughly 60.5 degrees of latitude in midsummer the gap never closes at all: the sun stops short of 6 degrees, evening civil twilight never ends, and none of that night can be logged. A fixed 30-minute allowance would hand you hours that do not exist there, and would start your night 10 minutes late every evening in the tropics.
How the sector is computed
The aircraft is walked along the great circle between the two aerodromes a minute at a time. At each step the sun's elevation is computed for that position and that instant, and the step counts as night when the centre of the disc is more than 6 degrees below the horizon. Every change between day and night is then bisected to a fraction of a second, so a crossing is placed rather than rounded to the sampling step.
The solar positions come from the NOAA algorithm, measured against US Naval Observatory published times to within two minutes. Give the optional take-off and landing times as well and the aircraft sits at each aerodrome for the taxi, instead of being treated as down-route while it is still on the ground.
What the tool does not model
It flies a great circle at a constant speed between the two aerodromes, on a spherical earth, so distances run about 0.3 per cent short of the WGS-84 figure and a twilight crossing shifts by a few seconds. It knows nothing about your routeing, a hold, a diversion or a re-route, so a track well off the direct line is a track it has not flown.
Without take-off and landing times it treats the whole block period as airborne, which models the aircraft as already moving down-route during the taxi. Fixing that is what the two optional inputs are for.
This is an aid for filling in a logbook, not an authority over it. The pilot remains responsible for what is logged, and for knowing which definition of night applies to the entry being made.
Good to know
Background and tips for getting the most out of this calculator.
Good to know
Background and tips for getting the most out of this calculator.Everything here is UTC
The date, the block times and the optional airborne times are all UTC, and every time printed back is UTC. A summer-time slip is the fastest route to a night entry that is exactly one hour wrong.
The two ends disagree
Civil twilight ends at a different clock time at each aerodrome, and the aircraft spends the sector between them. Both ends are shown, so the size of the disagreement is visible before you read the answer.
Coordinates for anything unlisted
The picker carries the busiest aerodromes worldwide. For a strip that is not in it, switch either end to coordinates and type a latitude and a longitude in degrees, positive north and positive east.
Frequently asked questions
Tap to read the full background and answers.
Frequently asked questions
Tap to read the full background and answers.- What counts as night in an EASA logbook?
- Night is bounded by civil twilight, not by sunset. SERA, Annex, definition (97) puts it between the end of evening civil twilight and the beginning of morning civil twilight, and fixes civil twilight at the centre of the sun's disc 6 degrees below the horizon. Both the SERA and the Part-FCL wordings are quoted in full in the explanation below. This calculator applies the 6-degree test at the position of the aircraft, not at the aerodrome you left.
- Does Part-FCL define night the same way?
- Almost, and the difference decides what you log. Point FCL.010 repeats the civil-twilight wording and then allows a Member State to prescribe some other period between sunset and sunrise instead. Where your authority has prescribed one, that period governs the licensing side. This tool computes the civil-twilight definition, so check what your own authority has prescribed before logging a figure from it.
- Is night simply the time after sunset?
- No, and no fixed allowance repairs it. The gap between sunset and the end of civil twilight is 20 minutes at Singapore on the March equinox, 35 minutes at Manchester on 15 October 2026, 61 minutes at Copenhagen on the June solstice and 98 minutes at Stockholm on that same night, all computed with this tool. One rule of thumb cannot cover a spread that wide.
- How does the FAA define night?
- With two rules for two purposes. 14 CFR 1.1 defines night as the time between the end of evening civil twilight and the beginning of morning civil twilight, which is what night flight time is logged against. 14 CFR 61.57(b), the night passenger-carrying recency rule, uses a narrower period: one hour after sunset to one hour before sunrise. A landing can be night for the logbook and still fall outside the window that counts for currency.
- What about a flight in the far north in summer?
- Above roughly 60.5 degrees of latitude around the June solstice the sun never reaches 6 degrees below the horizon, evening civil twilight never ends, and there is no night to log. The tool says so in words instead of printing a time that does not exist. The polar winter is the mirror image: at Tromso on the December solstice the sun never rises, yet civil twilight still runs from 08:32 to 12:53 UTC.
- Do I enter local time or UTC?
- UTC, everywhere. One summer-time slip puts the answer an hour out. An on-block time earlier than the off-block time is read as the next UTC day, which is how a sector across midnight is entered, so two identical times are refused as a typo rather than read as a 24-hour sector.
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The definition of night used here is the civil twilight one, read from Regulation (EU) No 923/2012 and Regulation (EU) No 1178/2011 on EUR-Lex. Part-FCL allows a Member State to prescribe a different period between sunset and sunrise for licensing purposes, so check what your own authority has prescribed before logging a figure from this page. Positions are interpolated along a great circle on a spherical earth and take no account of routeing, holding or diversion. The pilot remains responsible for what goes in the logbook.
Last reviewed July 2026