How this instrument works
Time-lapse photography compresses a long real-world duration into a short video by capturing frames at a slow interval and playing them back at a normal video frame rate. This calculator answers the two questions every time-lapse shoot needs answered before pressing the shutter: how many total frames will the shoot produce, and how many seconds of final footage will that turn into once played back.
The number of frames captured is simply the total shoot duration divided by the interval between shots -- shoot for 60 minutes at a 5-second interval and you'll capture 720 frames. Playback duration then depends on frame rate: those 720 frames, played back at the cinema-standard 24 frames per second, run for exactly 30 seconds of finished video, regardless of how long the original shoot took to capture them.
Getting the interval right matters: too short an interval wastes storage and produces more frames than needed for a smooth result, while too long an interval can make fast-changing subjects, like clouds, crowds or construction, look jerky rather than smooth once sped up. This calculator lets you test different intervals against your available shoot time before committing a memory card and battery to the actual capture.
- Enter Total shoot duration (minutes) -- how long you'll be capturing frames for, e.g. 60 for a one-hour shoot.
- Enter Interval between frames (seconds) -- how often the camera fires, typically set on an intervalometer.
- Enter Playback frame rate (fps) -- the frame rate of your finished video, commonly 24, 25 or 30fps.
- Read Number of frames captured and Playback duration, in seconds and minutes, beneath the inputs.
- Shorten the interval or lengthen the shoot to get more frames and a longer final clip, at the cost of more storage and shooting time.
Worked example -- 60-minute shoot at a 5-second interval
Enter a 60-minute total shoot duration, a 5-second interval between frames, and a 24fps playback frame rate. Number of frames captured comes out to floor((60 x 60) / 5) = floor(720) = 720 frames. Playback duration is 720 / 24 = 30 seconds, or exactly 0.5 minutes -- a full hour of real time compressed into a 30-second clip.
Questions
How do I choose the right interval for my time-lapse subject?
It depends on how fast your subject changes: slow-moving subjects like clouds or a sunset typically work well with a 3-10 second interval, moderately paced subjects like construction or plant growth often use intervals from minutes to hours, and fast subjects like crowds of people or traffic can use intervals under 2 seconds to avoid a jerky, strobing result once sped up. A shorter interval always produces a smoother-looking time-lapse, at the cost of more frames and storage.
Why does playback frame rate change the length of my finished clip?
Because the same number of captured frames plays back faster or slower depending on how many are shown per second -- 720 frames at 24fps runs 30 seconds, but the identical 720 frames at 30fps runs only 24 seconds, since more frames are displayed each second. Choosing a playback frame rate is really choosing how much you're compressing the original shoot duration into the final clip.
What playback frame rate should I use for my time-lapse?
24fps is the traditional cinema standard, unchanged since the introduction of sound film in the late 1920s, and gives time-lapse footage a familiar 'film' look. 30fps is the standard NTSC video frame rate common in North American broadcast and web video, while 25fps is the PAL standard used across much of Europe and Asia -- any of the three work technically; the choice mostly comes down to matching the rest of your project's convention.
How many frames do I need for a time-lapse of a specific length?
Multiply your target playback duration in seconds by your chosen frame rate -- a 10-second clip at 24fps needs 240 frames. Then work backward to find your interval: divide your planned shoot duration, in seconds, by that frame count to get the interval between shots. This calculator's formula runs the opposite direction, from shoot duration and interval to frame count and playback length, so plan your target length first, then adjust the inputs to match.
Does a shorter interval always make a better time-lapse?
Not necessarily -- a shorter interval produces more frames and a smoother result, but it also means more storage used, more battery drained, and more images to process afterward, with diminishing visual benefit once the interval is already short enough to avoid jerkiness for your specific subject. Matching interval to how fast the subject actually changes generally gives the best trade-off between smoothness and practicality.