Frame Rate Calculator — FPS, Shutter Angle & Slow Motion ToolFrame RateCalculator

24fps (actually 23.976fps for NTSC) is the standard cinema frame rate used in theatrical films worldwide. 25fps is the PAL standard used in European broadcast television. The difference stems from historical electrical frequency standards: 60Hz in North America led to 29.97/23.976fps, while 50Hz in Europe led to 25/50fps. For web delivery, either works, but mixing them on a timeline causes stuttering and audio sync issues. Most international co-productions shoot at 24fps for universal compatibility.

The 180 degree shutter rule is a cinematography guideline stating your shutter speed should be double your frame rate for natural-looking motion blur. The name comes from rotary disc shutters in film cameras, where a 180-degree opening exposes the film for exactly half the frame duration. At 24fps this gives 1/48s, at 25fps it gives 1/50s, and at 30fps it gives 1/60s. Breaking this rule creates distinct looks: a narrower angle (e.g., 90°) produces staccato, sharp movement like in Saving Private Ryan, while a wider angle (270–360°) gives dreamy, smeared motion blur.

23.976fps (often written as 23.98) exists because of NTSC color television. When color was added to the NTSC broadcast standard in the 1950s, the frame rate was slowed by a factor of 1000/1001 to prevent interference between the color subcarrier and audio frequencies. This gave 29.97fps for interlaced broadcast and 23.976fps for progressive cinema content. True 24.000fps is still used in theatrical DCP projection, but virtually all digital camera workflows use 23.976fps for NTSC compatibility.

Divide the playback frame rate by the capture frame rate and multiply by 100 to get speed percentage. For example: shooting at 120fps and playing back at 24fps gives (24 ÷ 120) × 100 = 20% speed, which is 5× slower. A 1-second real-time event captured at 120fps will play back over 5 seconds at 24fps. To find recording time needed: multiply the desired playback duration by (playback fps ÷ capture fps). For 10 seconds of 5× slow-mo at 24fps, you need 10 × (24 ÷ 120) = 2 seconds of recording.

Shutter angle describes exposure time as a proportion of the frame period, originating from rotary disc shutters in film cameras. A 360° angle means the sensor is exposed for the entire frame duration; 180° means half. Shutter speed is an absolute duration (e.g., 1/48s). The key advantage of shutter angle is consistency: a 180° angle always produces the same motion blur character regardless of frame rate, whereas a fixed shutter speed of 1/48s would look different at 24fps versus 60fps. Most cinema cameras display both options.

Match your shutter speed to a multiple of the electrical frequency. In 50Hz regions (Europe, most of Asia, Africa), use 1/50s, 1/100s, or 1/200s. In 60Hz regions (North America, parts of Japan), use 1/60s, 1/120s, or 1/240s. At 24fps, a 172.8° shutter angle gives exactly 1/50s for flicker-free shooting under 50Hz lighting. At 25fps, the standard 180° already gives 1/50s. LED lights may flicker at different frequencies than their power source, so always test with your specific fixtures.

For standard YouTube content, 24fps or 30fps are the most common. 24fps gives a cinematic look, while 30fps feels smoother and is preferred for talking-head videos, vlogs, and tutorials. For gaming content, 60fps is standard. If you plan to add slow motion in post, shoot B-roll at 60fps or 120fps and conform to your 24/30fps timeline.

At 60fps played back at 24fps, you get 2.5× slow motion (40% speed). At 30fps playback, you get 2× slow motion (50% speed). This is subtle slow motion — enough to smooth out action and add a slightly dreamy quality, but not dramatic. For more noticeable slow motion (5× or more), you need 120fps or higher capture rates.

Most narrative cinema is shot at 24fps (or 23.976fps for NTSC compatibility). European productions and broadcast content often use 25fps. High frame rate (HFR) experiments like The Hobbit used 48fps. For slow motion, cinema cameras like the RED V-Raptor can shoot up to 600fps at reduced resolution, and specialized cameras like the Phantom Flex4K can reach 1000fps at 4K.

Overcranking means shooting at a higher frame rate than playback speed, resulting in slow motion. The term comes from manually cranking film cameras faster. For example, shooting at 120fps and playing back at 24fps is overcranking. Undercranking is the opposite — shooting at a lower frame rate (e.g., 12fps played at 24fps) creates a sped-up, jittery look often used for comedy or chase sequences.