Wake at 5:00 am
Four bedtimes, each one a whole number of sleep cycles before the alarm, with a quarter of an hour allowed for actually falling asleep.
Go to bed at 9:15 pm
5 cycles and 7h 30m asleep: the row nearest eight hours.
| Get into bed | Cycles | Time asleep |
|---|---|---|
| 7:45 pm | 6 cycles | 9h |
| 9:15 pm | 5 cycles | 7h 30m |
| 10:45 pm | 4 cycles | 6h |
| 12:15 am | 3 cycles | 4h 30m |
7h 30m asleep
The night nearest eight hours, laid on a clock face.
The two assumptions
Move either one and every time above moves with it. The settings follow you around the site.
What a 5:00 am alarm asks of the evening
Five o'clock pulls every row of the table back into the evening. Six cycles means lights out at 7:45 pm, five cycles at 9:15 pm, and four cycles at 10:45 pm. Three cycles, at 12:15 am, is the only row that crosses midnight, and it is the one row that leaves the evening whole.
In London a 5:00 am alarm goes off in daylight only from late May to the middle of July, when sunrise comes as early as 4:43 am. For the rest of the year it rings in the dark, and from the middle of December to the middle of January the sun is not up until after 8:00 am, three hours later. In New York the earliest sunrise of the year is 5:24 am, so this alarm is dark on every day of the year. Johannesburg's earliest sunrise, 5:07 am at the end of November, misses it by seven minutes, and Cape Town and Sydney are later still.
The six-cycle bedtime of 7:45 pm comes before sunset in London from about the second week of April to the start of September, and in New York from late April to late August. South of the equator the months swap over: in Cape Town it is light at 7:45 pm from early December to early February, and in Sydney from late November to the middle of February. Johannesburg never gets there, because its latest sunset of the year is 7:05 pm. The five-cycle bedtime of 9:15 pm is in daylight in London alone, and only from about 9 June to 10 July.
Every bedtime on this page comes before the clocks change, which is never earlier than 1:00 am in any of these cities. On the night they go forward, each row gives an hour less in bed than the table says, and on the night they go back, an hour more. Johannesburg and Cape Town keep the same clock all year, so there the table holds every night.
With the shift planner's default of an hour and a half between the alarm and the start, 5:00 am is the alarm for a shift that starts at 6:30 am. The early rota on the planner starts at 6:00 am and asks for 4:30 am instead.
Further afield, Tokyo's earliest sunrise is 4:25 am, so there a 5:00 am alarm is light from late April to the middle of August. Moscow has almost the same stretch, with sunrise as early as 3:44 am in June. In Beijing it is light from the middle of May to the middle of July, and in Berlin for the same weeks as London. Madrid, on the same clock as Berlin but seventeen degrees further west, never sees the sun before 6:44 am. Nowhere near the equator gets there either: Singapore's sunrise never comes before 6:46 am and Nairobi's never before 6:11 am. Chicago, Toronto and Los Angeles are dark at 5:00 am on every day of the year as well.
Sunrise and sunset: the NOAA solar equations, for each city centre in 2026, to the nearest minute.
Every time on this page comes from two numbers: a cycle of 90 minutes and 15 minutes between getting into bed and being asleep. Neither is a measurement of you. The reference pages say where each one comes from.
A quarter of an hour either way
If the alarm is set to something near but not exactly 5:00 am, the table for it is a page of its own.
The other direction
Already in bed and deciding when to set the alarm? The sleep-now page runs the same sum forwards from the time where you are.