A time-lapse turns hours of real time into seconds of video. This calculator works out the exact interval to program into your intervalometer so your final clip lands at the length you want, at the frame rate you want. It also tells you the total shot count and storage requirement so there are no surprises when you arrive on location.
How it works
Three values define every time-lapse:
Total frames = clip length (s) × playback frame rate (fps)
Interval = real-world duration (s) ÷ total frames
Speed-up factor = real-world duration ÷ clip length
So if you want a 20-second clip at 24 fps, you need 480 frames. Spreading those 480 frames across
a two-hour (7,200-second) event gives an interval of 7,200 ÷ 480 = 15 seconds per shot, and the
finished clip plays 360× faster than real life.
Worked example — sunset-to-night sequence
You want to capture a 4-hour sunset-to-night sequence as a 30-second clip at 30 fps:
- Total frames = 30 × 30 = 900
- Interval = 14,400 s ÷ 900 = 16 seconds
- Speed-up = 14,400 ÷ 30 = 480× faster
At 12 MB per RAW frame, that is 900 × 12 ≈ 10.5 GB of storage. A 64 GB card is safe; a 32 GB card is marginal. Shooting JPEG at 4 MB per frame would need only about 3.5 GB, a useful trade-off when you only have a smaller card available.
How subject speed affects the interval
The right interval depends on how fast your subject actually moves through the frame. A cloud that crosses the sky in 10 minutes needs a much shorter interval than a glacier calving event that takes hours. As a starting guide:
| Subject | Recommended interval |
|---|---|
| Fast clouds / traffic | 1–3 seconds |
| Sunsets / building sites | 3–6 seconds |
| Slow cloud formations | 8–15 seconds |
| Celestial objects / stars | 20–40 seconds |
| Plant growth / tidal change | 1–5 minutes |
These are starting points. Calculate the exact interval you need for your chosen clip length, then check it falls within the right range for your subject — if it doesn’t, adjust clip length or coverage duration until it does.
Battery and mechanical considerations
Long time-lapses drain batteries faster than continuous video because the sensor, display, and card all wake briefly for every shot. In cold weather, battery drain accelerates further. Count your expected shot total, multiply by the per-shot energy draw of your camera, and bring a spare battery or an external power bank if the run time exceeds a few hours.
Shutter actuations also matter. Consumer mirrorless and DSLR cameras typically last 100,000–300,000 actuations. A 1,000-frame sequence is trivial; a 10,000-frame one is meaningful if you shoot frequently. Mirror-less cameras with electronic shutters bypass this limit entirely for time-lapses.
Interval vs exposure: the critical constraint
The interval must always be longer than the exposure plus card-write time, or the camera skips a frame and the clip runs short. For a 15-second interval, keep exposure to 5–10 seconds maximum, leaving 5–10 seconds for the card to write. When shooting in very low light with long exposures, the calculated interval may need to be stretched beyond what the maths requires for motion smoothness.
All maths runs locally in your browser; nothing about your shoot is uploaded.