How to use the slideshow length calculator
- Enter the number of photos and the seconds each photo stays on screen.
- If your editor adds a pause between photos, enter it as the transition. Leave 0 when transitions overlap the photos.
- Open More options to add a title slide, a closing slide, or a target length such as the length of a song.
- Read the total in minutes and seconds, then adjust the seconds per photo until it suits the occasion.
Formula
runtime = photos x seconds per photo + (photos - 1) x transition + title seconds + closing seconds
seconds per photo to fit a target = (target seconds - transitions - title - closing) / photos
A transition is counted once between each pair of photos, so n photos have n - 1 transitions. The result is shown as minutes and seconds, and also as total seconds and decimal minutes for editing software.
120 photos at 5 seconds each
One hundred twenty photos at 5 seconds each run 120 x 5 = 600 seconds, which is exactly 10:00.
Add a 1 second transition between photos, a 3 second title slide and a 4 second closing slide. The 119 transitions add 119 seconds, so the total is 600 + 119 + 3 + 4 = 726 seconds, or 12:06. To fit the same 120 photos into 10 minutes with 1 second transitions, each photo gets (600 - 119) / 120 = 4.01 seconds.
Choosing seconds per photo
The right pace depends on the photos and the viewers. A simple portrait may need only a few seconds, while a group photo or a photo with writing on it needs longer. Rather than trusting a single number, run the slideshow once and see whether the pace feels rushed or slow, then adjust here.
If the show goes with music, use the target length option. Enter the length of the song in minutes and the page tells you how many seconds each photo can stay on screen so the last photo ends with the last note.
Related planning
To pick songs for the same event, use the Party Playlist Length Calculator. To lay photos out on a single page instead, try the Image Collage Maker. If the show is part of a larger day, the Wedding Day Timeline Generator can hold a slot for it.
Assumptions and limits
- Every photo is shown for the same number of seconds.
- Transitions are added between photos. If your editor overlaps them with the photos, enter 0.
- Video clips, captions and music fades are not modeled.
- Nothing is uploaded. The arithmetic runs in your browser.
Frequently asked questions
How long is a slideshow of 100 photos?
It depends on the seconds per photo. At 5 seconds each, 100 photos run 500 seconds, which is 8 minutes 20 seconds. At 3 seconds each they run 5 minutes.
How many photos do I need for a 3 minute song?
Divide 180 seconds by the seconds per photo. At 5 seconds each you need 36 photos, and at 4 seconds you need 45. Use the target length box to work backward from the song instead.
Do transitions add time to the slideshow?
Only if the next photo starts after the transition ends. Many editors overlap the two, so they add nothing. Enter the pause only when your editor adds it.
Why does the page show total seconds as well?
Video and slideshow editors often ask for a length in seconds or in decimal minutes, so the page shows both beside the minutes and seconds reading.