How to Calculate Filmmaking Math

The formulas behind everyday production math, each with a worked example you can check by hand.

How to Calculate Aspect Ratio

Get Your Resolution

Find the width and height of your video in pixels (e.g., 1920x1080)

Divide Width by Height

Divide the width by the height: 1920 ÷ 1080 = 1.778

Simplify the Ratio

Name the ratio: 1.778:1 is 16:9 (16 ÷ 9 = 1.778)

Formula

Aspect Ratio = Width ÷ Height

Example

Example: 3840 × 2160 (UHD) → 3840 ÷ 2160 = 1.778:1 = 16:9

Common Values

16:9 (1.78:1)1.85:1 (Flat)2.39:1 (Scope)4:3 (1.33:1)1:1 (Square)

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Aspect Ratio Calculator

How to Calculate Speed Percentage for Frame Rate Changes

Identify Your Frame Rates

Note the frame rate you shot at and the frame rate of your timeline

Apply the Formula

Speed % = (Playback FPS ÷ Shooting FPS) × 100

Interpret the Result

Less than 100% = slow motion, more than 100% = fast motion

Formula

Speed % = (Playback FPS ÷ Shooting FPS) × 100

Example

Example: 24fps playback ÷ 120fps shooting = 0.2 × 100 = 20% (5x slower)

Common Values

60fps→24fps = 40% (2.5x slower)120fps→24fps = 20% (5x slower)24fps→60fps = 250% (2.5x faster)

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Speed Change

How to Calculate Target Length Speed Adjustment

Measure Current Length

Get the current duration of your clip

Set Target Length

Determine the desired final duration for your clip

Calculate Speed Adjustment

Speed % = (Current Length ÷ Target Length) × 100

Formula

Speed % = (Original Duration ÷ Target Duration) × 100

Example

Example: a 2:00 clip to fit 1:30 = (120 s ÷ 90 s) × 100 = 133% speed

Common Values

2:00→1:30 = 133% (faster)1:00→1:30 = 67% (slower)3:00→2:00 = 150% (faster)

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Target Length

How to Add and Subtract Timecode

Align the Timecodes

Write timecodes in HH:MM:SS:FF format (Hours:Minutes:Seconds:Frames)

Add Each Component

Add frames, seconds, minutes, and hours separately

Handle Carry-Over

Convert excess frames to seconds, seconds to minutes, etc.

Formula

Remember: 25 frames = 1 second (at 25fps), 60 seconds = 1 minute

Example

Example: 01:23:45:12 + 00:45:30:18 = 02:09:16:05 (at 25fps)

Common Values

24fps = 24 frames per second25fps = 25 frames per second30fps = 30 frames per second

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Timecode Calculator

How to Calculate Target Bitrate

Determine File Size Limit

Know your target file size in MB or GB

Get Runtime Duration

Measure the total runtime of your video

Calculate Required Bitrate

Bitrate (Mbps) = (File Size in MB × 8) ÷ (Runtime in seconds)

Formula

Bitrate (Mbps) = (File Size in MB × 8) ÷ Runtime in seconds

Example

Example: 500MB file, 10 minutes = (500 × 8) ÷ 600 = 6.67 Mbps

Common Values

1GB per hour = ~2.2 Mbps500MB per 30 min = ~2.2 Mbps2GB per hour = ~4.4 MbpsSubtract audio (e.g. 0.32 Mbps) for the video bitrate

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Data & Storage

How to Calculate Upload Time

Check File Size

Get the exact file size in MB or GB

Test Upload Speed

Measure your actual upload speed in Mbps (not download speed)

Calculate Upload Time

Time = (File Size in MB × 8) ÷ (Upload Speed in Mbps) ÷ 60

Formula

Upload Time (minutes) = (File Size in MB × 8) ÷ Upload Speed (Mbps) ÷ 60

Example

Example: 2GB file, 10 Mbps upload = (2000 × 8) ÷ 10 ÷ 60 = 26.7 minutes

Common Values

1GB @ 10Mbps = ~13 minutes500MB @ 5Mbps = ~13 minutes4GB @ 20Mbps = ~27 minutes

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Upload Time

How to Calculate Recording Time from Storage

Check Available Storage

Find how much storage space you have available in GB

Determine Data Rate

Know your recording format's data rate in MB/min or Mbps

Calculate Recording Time

Time = Available Storage ÷ Data Rate per minute

Formula

Recording Time = Available Storage (MB) ÷ Data Rate (MB/min)

Example

Example: 64GB card, 4K H.264 at 100 Mbps (750MB/min) = 64000 ÷ 750 = 85 minutes (1h 25m)

Common Values

4K ProRes 422 (UHD, 23.976fps, 471 Mbps): ~3.5GB/min1080p H.264 at 50 Mbps: ~375MB/min4K H.264 at 100 Mbps: ~750MB/min

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Data & Storage

How to Calculate Storage Requirements from Recording Time

Plan Recording Duration

Determine how long you need to record in minutes

Check Format Data Rate

Find your recording format's data rate in MB/min

Calculate Storage Needed

Storage = Recording Time × Data Rate + 20% safety buffer

Formula

Storage Needed = Recording Time (min) × Data Rate (MB/min) × 1.2

Example

Example: 2 hours 4K ProRes 422 = 120 min × 3,533MB/min × 1.2 = 509GB needed

Common Values

1 hour 4K H.264 at 100 Mbps = ~45GB1 hour 1080p H.264 at 50 Mbps = ~22.5GB1 hour 4K ProRes 422 (UHD, 23.976fps) = ~212GB

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Data & Storage

How to Convert Timecode to Frames

Get Your Timecode

Note the timecode in HH:MM:SS:FF format (Hours:Minutes:Seconds:Frames)

Know Your Frame Rate

Identify the frame rate of your footage (e.g., 24fps, 30fps, 60fps)

Calculate Total Frames

Frames = (Hours × 3600 + Minutes × 60 + Seconds) × FPS + Frames

Formula

Total Frames = ((H × 3600) + (M × 60) + S) × FPS + F

Example

Example: 00:01:30:12 at 24fps = (0×3600 + 1×60 + 30) × 24 + 12 = 2172 frames

Common Values

1 second @ 24fps = 24 frames1 minute @ 30fps = 1800 frames1 hour @ 60fps = 216000 frames

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Timecode Calculator

How to Convert Frames to Timecode

Count Total Frames

Get the total number of frames you want to convert

Know Your Frame Rate

Identify the frame rate (24fps, 30fps, 60fps, etc.)

Calculate Each Component

Divide frames by FPS for seconds, then convert to HH:MM:SS:FF format

Formula

Hours = Frames ÷ (FPS × 3600), Minutes = remainder ÷ (FPS × 60), etc.

Example

Example: 2172 frames @ 24fps = 90.5 seconds = 00:01:30:12

Common Values

24 frames @ 24fps = 00:00:01:001800 frames @ 30fps = 00:01:00:007200 frames @ 60fps = 00:02:00:00

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Timecode Calculator

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