Random time generator
One outcome in 1,440
Drawn in your browser · nothing stored
A time appears as soon as the page loads, and the button draws another. The day holds 1,440 minutes and every one of them is equally likely, 00:00 and 23:59 included, so the draw is flat across the whole day rather than crowded into the hours a person would think of.
How to draw a random time
The reason to use a generator rather than think of a time is that people are extremely bad at picking one — asked for a random time, almost everyone lands on a round five or ten minutes, in daylight, and usually in the afternoon. A uniform draw does none of that: it produces 03:47 and 12:01 and 21:38 with exactly the frequency it produces 09:00, which is what makes it useful for sampling and useless for anything you want to feel plausible.
What the number actually is
A time of day is a count of minutes past midnight, and this page draws one whole number from 0 to 1,439 and formats it. Both ends are included, which is why the panel reads one outcome in 1,440 and not 1,439. The draw comes from the browser cryptographic generator with rejection sampling, so the fact that 1,440 is not a power of two introduces no bias toward the early hours, which is the quiet flaw in a naive modulus.
It is a clock reading and not a moment. There is no date attached and no time zone, and nothing here consults your clock, so 14:20 means the same thing in Auckland as in Lisbon and stays the same when the page is opened again tomorrow. That also means the two days a year that are not 1,440 minutes long, when the clocks go forward or back, have no bearing on it: a drawn 02:30 is a valid reading even in a local time zone where that minute does not exist on that particular night.
Repeats, and what the count does
Each draw is independent, so a batch can contain the same time twice. That is more likely than it feels: drawing twenty times from 1,440 minutes gives roughly a one in eight chance that two of them collide, which is the birthday problem and not a fault. If the times have to be distinct, draw them, look, and draw again if two match.
The limits worth knowing
The window is the whole day and cannot be narrowed here. That is deliberate rather than missing: the query this page answers is a random time, and a range is arithmetic. If you want office hours, draw a number from 540 to 1,020 on the random number generator and read it as minutes past midnight, because 540 is 09:00 and 1,020 is 17:00. The same trick is the only way to get a window across midnight, which no single range can express: 22:00 to 02:00 is 1,320 to 1,439 and 0 to 120, so draw from one or the other and accept that the first is slightly the larger span.
There are no seconds. Times are drawn and shown to the minute, so a sampling schedule that needs finer resolution wants a number from 0 to 86,399 instead. And nothing is stored: the times live in the page and a reload replaces them, which is exactly why the seed field exists. Announce a seed beforehand and anybody can reproduce the same schedule afterwards, which is the difference between a random schedule and a defensible one.
What people use it for
- Scheduling unannounced spot checks that cannot be anticipated
- Picking observation times for a survey or a study
- Building test data whose timestamps are not clustered on the hour
- Setting a time for a game, a prompt or a drill
- Choosing when to run a job so a fleet does not all start at once
Questions
Yes, one in 1,440. There is no lean toward working hours, round numbers or the top of the hour.
Yes. 00:00 and 23:59 can both come up, which is why the pool reads 1,440 and not 1,439.
No. Times are drawn to the minute. For finer resolution, draw a number from 0 to 86,399 and read it as seconds past midnight.
Twenty-four hour, so 13:05 rather than 1:05 pm. Subtract twelve from anything above 12:59 to read it the other way.
Not on this page, where the window is the whole day. Draw a number from 540 to 1,020 on the random number generator and read it as minutes past midnight.
Not as one range, because a range cannot wrap. 22:00 to 02:00 is 1,320 to 1,439 plus 0 to 120; draw from whichever, keeping in mind the two spans are not the same length.
More likely than it feels. Draws are independent, so twenty of them carry roughly a one in eight chance that two land on the same minute. That is the birthday problem rather than a fault.
Up to twenty. The slider sets the count and the whole batch redraws when you move it.
Type a seed before drawing. The same seed and the same count always give the same times, so a schedule can be checked after the fact.
None. It is a clock reading rather than a moment, with no date and no zone attached, and nothing here reads your clock.
It has no bearing on the draw. Every minute from 00:00 to 23:59 is drawn regardless of whether a particular local night actually contains it.
The draw uses crypto.getRandomValues with rejection sampling, so 1,440 not being a power of two introduces no bias toward the early hours.
Only with a seed announced in advance. Without one there is nothing for anyone to check afterwards.
No. The times live in this tab and a reload replaces them. Copy them out before you leave.