Free calculator
Time-Lapse Calculator
A one-hour event played back as a 10-second clip at 24 fps needs 240 frames, one every 15 seconds, and plays 360 times faster than real time. Enter how long you will shoot, how long the clip should run and its frame rate to get the interval to set on the camera.
Free, no sign-up. Runs in your browser.
This web tool uses the formulas of the Time Lapse calculator in the CineMath app, also gives the exact interval, prints the formula with your inputs as typed, and needs a clip of at least one frame. Save, share and get the Pro tools in the app.
How it works
frames = clip × fps
interval = real ÷ frames
speed-up = real ÷ clipPut the real duration in seconds (minutes × 60). The frame count is shown to the nearest frame, but the interval is worked out from the exact figure: 10 seconds at 23.976 fps is 239.76 frames.
Where
- real
- How long the event lasts, in real time(s)
- clip
- How long the finished clip runs(s)
- fps
- The timeline rate the frames will play at(fps)
under 1 s → ms
under 60 s → sec
60 s and up → minSeconds and minutes are shown to one decimal place, milliseconds to the nearest whole one. The calculator warns when the interval is under a second, and when the plan needs more than 10,000 frames.
Fitting the exposure inside the interval
The exposure and the camera's write time both have to fit between shots: a 25-second star exposure cannot run at a 20-second interval. An exposure of about half the interval gives smooth, blurred motion; a short one gives a crisper, more staccato look. The time-lapse guide covers exposure, card space and long-term shoots, and hyperlapse and day-to-night covers ramping the exposure as the light changes.
Worked example
A two-hour sunset into a 10-second clip at 23.976 fps
- Frames: 10 s × 23.976 fps = 239.76, so shoot 240
- Interval: 7,200 s ÷ 239.76 = 30.03 s
- Speed-up: 7,200 s ÷ 10 s = 720×
Set the intervalometer to 30 seconds: 240 frames, 720× faster than real time.
Quick reference
Interval at 24 fps, by event length and clip length
| Event | 5 s clip | 10 s clip | 15 s clip | 30 s clip |
|---|---|---|---|---|
| 30 min | 15.0 sec | 7.5 sec | 5.0 sec | 2.5 sec |
| 1 hour | 30.0 sec | 15.0 sec | 10.0 sec | 5.0 sec |
| 2 hours | 1.0 min | 30.0 sec | 20.0 sec | 10.0 sec |
| 4 hours | 2.0 min | 1.0 min | 40.0 sec | 20.0 sec |
| 8 hours | 4.0 min | 2.0 min | 1.3 min | 40.0 sec |
Save, share and get the Pro tools in the CineMath app
CineMath is a free download for iPhone, iPad and Mac, with this calculator built in. In version 1.3, coming soon to the App Store, CineMath Professional saves calculations to your history, shares them as links, and adds the Camera Database and Data Planning.
Questions
How do I work out a time-lapse interval?
Multiply the clip length in seconds by the frame rate to get the frames you need, then divide the event length in seconds by that number. A one-hour event into a 10-second clip at 24 fps is 3,600 ÷ 240 = 15 seconds between shots.
How many photos do I need for a 10-second time-lapse?
At 24 fps, 240; at 25 fps, 250; at 30 fps, 300. The count depends only on the clip length and the frame rate, not on how long the event lasts. Shooting a few extra gives you room to trim the start and end.
What interval should I use for a sunset?
Plan from the shot you want. For a two-hour sunset in a 10-second clip at 24 fps, shoot every 30 seconds. Shorter intervals make motion smoother and give a longer clip; a common range for sunsets and slow clouds is 5 to 10 seconds if you want more frames to choose from.
Why does the calculator warn about intervals under 1 second?
Each exposure, plus the time the camera takes to write the file, has to fit inside the interval. Below a second, many cameras cannot keep up, especially with raw files, so check your camera can shoot and save at that rate, or shoot video and speed it up instead.
Should I use 23.976 or 24 fps?
Use the frame rate of the timeline the shot will sit in. At 23.976 a 10-second clip is 239.76 frames, so you shoot 240, and the interval for a two-hour event becomes 30.03 seconds instead of 30: the same setting on the camera.
What does the long-shoot warning mean?
Plans over 10,000 frames get a reminder of how many hours the shoot runs. At 24 fps that is a clip longer than about 7 minutes. Check the card space, the battery or mains power and the weather will last the whole shoot.