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Frame Rate Converter

Convert between frame rates, get the exact per-frame duration in milliseconds, and see how your clip length changes.

Free · No sign-up · Runs in your browser
Frame duration @ 30fps
33.33ms
Frames @ 30fps
300frames
Source frames @ 60fps
600frames
Conformed length
20.00s
Conformed length is what you get if you play the 60fps frames back at 30fps without resampling — useful for speed ramps and timelapse math.
HOW IT WORKS
01

Set source & target fps

Choose the frame rate you have and the one you want.

02

Enter clip length

Type how many seconds your clip runs.

03

Read the math

Get per-frame duration, total frames, and the conformed length.

Frame rate, frame duration, and clip length

Frame rate (fps) is how many still images play per second. Its inverse is frame duration — the milliseconds each frame stays on screen. Knowing both is essential when you cut on exact frames, sync audio, build animations, or plan slow-motion and timelapse effects.

Resample vs conform

There are two ways to "convert" frame rate. Resampling keeps duration and speed constant by adding or dropping frames — what an editor does when you change project fps. Conforming reinterprets the existing frames at a new rate, which changes speed: 60fps footage conformed to 24fps becomes smooth slow motion. The conformed-length output above is the math behind that.

ScreenBuddy for Mac records smooth high-frame-rate screen capture and lets you speed up or slow down sections on the timeline. See the app.

FAQ

Frequently Asked Questions

How many milliseconds is one frame at 30fps?
One frame at 30fps lasts 33.33 ms (1000 ÷ 30). At 24fps it is 41.67 ms, at 25fps 40 ms, and at 60fps 16.67 ms. The calculator shows this instantly for your target frame rate.
What happens when I convert 60fps to 30fps?
It depends on intent. If you "resample" to keep the same duration, the tool drops every other frame and the clip stays the same length. If you "conform" the frames to 30fps, the same 60fps frames now take twice as long to play, creating a 50% slow-motion effect — the conformed-length output shows exactly how long it becomes.
Does changing frame rate change video speed?
Only if you conform without resampling. Re-timing the existing frames to a different fps changes the playback speed (the basis of slow-motion and timelapse). Proper frame-rate conversion that resamples keeps speed constant by interpolating or dropping frames.
Which frame rate should I record at?
30fps is the safe default for screen recordings and talking-head video. 60fps is better for fast motion, gameplay, and smooth cursor movement. 24fps gives a cinematic look. Match your delivery platform and your source content.
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