Shutter Angle Calculator

Convert a cine shutter angle and frame rate into the equivalent shutter speed — the 180° rule for natural motion blur and beyond. Calculated in your browser.

Shutter speed

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Exposure time per frame-

Show the math

A rotary shutter exposes each frame for a fraction of its duration set by the angle:

shutter time = angle ÷ (360 · fps)

The classic 180° angle gives the natural-looking motion blur of film, at 24 fps that is a 1/48 s shutter (rounded to 1/50 in practice).

All math runs in your browser.

What this does

A shutter angle calculator converts a cine shutter angle and frame rate into the equivalent shutter speed — the 180° rule for natural motion blur and beyond.

How to use it

  1. Enter the frame rate.
  2. Enter the shutter angle.
  3. Read the equivalent shutter speed.
  4. Compare to the 180° baseline.

How it works

A rotary shutter exposes each frame for that fraction of a second. A 180° angle — half the frame interval — gives the motion blur audiences read as natural.

shutter speed = angle ÷ (360 × fps)

Understanding your result

The 180-degree result is the reference because it produces the motion blur audiences read as natural, halve the angle and motion looks crisp and stuttery (the classic war-film look), widen it and fast action smears. So choose the angle for the feel you want, then let the calculator give the shutter speed, rather than picking a shutter speed first and getting unnatural motion by accident.

Example

180° at 24 fps is a 1/48 s shutter.

Sources & methodology

Last updated .

Frequently asked questions

How is shutter angle converted?

A rotary shutter exposes each frame for angle ÷ (360 × fps) seconds, so a 180° angle at 24 fps gives a 1/48 s shutter.

What is the 180-degree rule?

Setting the shutter angle to 180° (half the frame interval) produces the motion blur audiences associate with natural-looking film and video.

Is anything uploaded?

No. Everything is calculated in your browser — nothing you enter leaves your device.