By Ahsan Khowaja · Updated 27 October 2026
How to use the time lapse calculator
- Choose what you already know. Most people know the event length and interval and want the photo count and clip length. If you know how long the finished clip must be (a 30-second social post, say), choose the interval mode. If you have fixed the interval and clip length, the shooting time mode tells you how long to leave the camera running.
- Enter the event length in hours, minutes or seconds, and the interval, the gap between one photo and the next, in seconds.
- Pick the playback frame rate your editor will use: 24 or 25 fps for a film look, 30 fps for most online video, 50 or 60 fps for very smooth motion.
- Set the average photo size from a recent file on your card. Raw files from a 24-megapixel camera are often 20–40 MB each; a fine JPEG 5–12 MB; a phone HEIC 2–4 MB.
The results update as you type, and the table under them shows what other intervals would give for the same event, so you can see the trade-off before you set the intervalometer. You don't need a time lapse calculator app for this: the page works offline once loaded and fits a phone screen.
The time-lapse formulas
Everything a timelapse calculator does comes from four lines of arithmetic:
- Photos = event length ÷ interval. Both in seconds. 2 hours is 7,200 s; at a 5 s interval that is 1,440 photos. The calculator rounds down, because a 7,203-second event still only fits 1,440 whole intervals.
- Clip length = photos ÷ frame rate. 1,440 photos at 30 fps play for 48 s. The same photos at 24 fps run 60 s, so turning timelapse frames to video length depends on the editor setting as much as on the shoot.
- Speed-up = interval × frame rate. 5 s × 30 fps = 150×: each second of video covers 2 minutes 30 seconds of real time. This is the number that decides how clouds, people or shadows will move.
- Storage = photos × average file size. 1,440 × 25 MB = 36,000 MB, which is 36 GB on a card label (card makers count 1 GB as 1,000 MB).
The interval mode rearranges the first two lines: photos = clip length × frame rate, then interval = event length ÷ photos. An 8-hour workday compressed into a 30 s clip at 30 fps needs 900 photos, one every 32 s.
Worked examples
| Event | Interval | Frame rate | Photos | Clip length | Speed-up | Storage at 25 MB |
|---|---|---|---|---|---|---|
| 2 h | 5 s | 30 fps | 1,440 | 48 s | 150× | 36 GB |
| 45 min sunset | 3 s | 24 fps | 900 | 37.5 s | 72× | 22.5 GB (10.8 GB at 12 MB) |
| 24 h | 30 s | 30 fps | 2,880 | 1 min 36 s | 900× | 72 GB |
| 8 h, 30 s clip wanted | 32 s | 30 fps | 900 | 30 s | 960× | 22.5 GB |
| 20 s clip at 10 s interval | 10 s | 25 fps | 500 | 20 s | 250× | 12.5 GB, shoot for 1 h 23 min 20 s |
The 24-hour row shows why long events need long intervals: at 5 s instead of 30 s the same day would be 17,280 photos and 432 GB, for a 9 min 36 s clip nobody will watch to the end.
Time lapse interval chart: starting points by subject
| Subject | Interval | Why |
|---|---|---|
| Fast clouds, busy street, people | 1–3 s | Movement is already quick; a long gap makes it jerky |
| Slow clouds, sunset, sunrise | 3–10 s | Light changes over 30–60 min; 5 s gives a 20–40 s clip |
| Shadows crossing a room, tides | 10–30 s | Hours of change into a short clip |
| Night sky and star trails | 20–30 s | The interval is set by the long exposure each frame needs |
| Plants, flowers, melting ice | 1–10 min | Change takes hours or days |
| Construction, seasons | 15 min to several hours | Months of shooting, often one frame per daylight hour |
These are starting points photographers commonly use, not rules. The deciding factor is the time lapse speed you want: pick the clip length first, work out the interval, then check that the speed-up looks natural for the subject. Clouds at 150× glide; at 900× they strobe.
Shutter speed, flicker and the interval
The interval must be longer than the exposure plus the time the camera needs to write the file. A 2 s interval with a 1/2 s exposure and a 1 s raw write is already tight; many cameras buffer and then stall, which leaves gaps. Leave at least half a second of margin, or shoot JPEG for short intervals.
For smooth motion, many shooters keep the shutter open for roughly half the interval (a 2 s exposure in a 5 s interval), which is the same 180° shutter convention used in video. That usually needs an ND filter in daylight; the exposure calculator works out how strong. Shooting fully manual (fixed aperture, shutter, ISO and white balance) prevents the brightness flicker that automatic modes introduce between frames.
Storage and the memory card
Time lapse storage adds up faster than normal shooting because you take hundreds of frames you would never take by hand. Multiply the photo count by a real file size from your camera: the 25 MB default suits a 24 MP raw file, but a 45 MP camera can produce 50 MB raws and a phone JPEG may be 3 MB. If the clip is only going online, a 1080p or 4K export needs far less resolution than the camera gives, so you can shoot medium JPEGs and lose nothing visible. The photo storage calculator sizes a whole card or drive, and the video file size calculator tells you how big the exported clip will be.
Looking for elapsed time instead?
"Time lapse" is also what people type when they mean the time that has passed between two clock times, such as 9:15 to 17:40. That is an elapsed time calculator, not a photography tool. Our hours calculator is the time duration calculator for hours and minutes between two times, and the time calculator adds and subtracts hours, minutes and seconds.
