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Target Length Calculator

Calculate required frame rate to achieve specific runtime from source material

Purpose

The Target Length Calculator determines the exact speed percentage and effective frame rate needed to fit source material into a specific target duration. Essential for broadcast timing and content that must fit precise time slots.

When to Use

Common Scenarios

  • • Fitting 2 hours of 24fps footage into exactly 110 minutes for broadcast
  • • Matching content to specific commercial time slots
  • • Creating content for exact streaming platform requirements
  • • Adjusting archive material to modern broadcast standards
  • • Synchronizing multiple clips to a master timeline

Professional Applications

  • • Broadcast programming schedules
  • • Commercial break timing
  • • Festival submission requirements
  • • Educational content time limits
  • • Live event timing constraints

Step-by-Step Guide

  1. Select Target Length Calculator

    Choose from the calculator types row

  2. Set Frame Rate

    Use the dropdown to select your working frame rate (affects timecode calculations)

  3. Enter Clip Length (Current Duration)

    Input your source material's current duration:

    • Hours: 00-23
    • Minutes: 00-59
    • Seconds: 00-59
    • Frames: 00 to (fps-1)
  4. Enter Target Length (Desired Duration)

    Use the same format to enter your desired final duration

  5. View Results

    Shows the required speed percentage and new effective frame rate

Example Calculations

Real-World Examples

Film to Broadcast Slot
Clip Length: 02:00:00:00 (2 hours)
Target Length: 01:50:00:00 (110 minutes)
Frame Rate: 24 fps
109.09% speed
Effective: 26.18 fps
Commercial Break Timing
Clip Length: 00:30:15:00
Target Length: 00:30:00:00
Frame Rate: 29.97 fps
99.17% speed
Effective: 29.72 fps
Festival Requirements
Clip Length: 01:32:45:12
Target Length: 01:30:00:00
Frame Rate: 23.976 fps
103.06% speed
Effective: 24.71 fps
Educational Content
Clip Length: 00:22:30:00
Target Length: 00:20:00:00
Frame Rate: 25 fps
112.50% speed
Effective: 28.13 fps

Understanding Results

Speed Percentage

  • • Above 100%: Content will play faster and shorter
  • • Below 100%: Content will play slower and longer
  • • Exactly 100%: Source already matches target length

Effective Frame Rate

This is the theoretical frame rate your content will appear to have after speed adjustment:

  • • Useful for planning audio pitch correction
  • • Helps determine quality impact of speed change
  • • Reference for motion blur expectations

Pro Tips

📐 Timing Precision

  • • Always verify audio sync after speed changes
  • • Consider using optical flow for better quality on large changes
  • • Small changes (under 5%) are often imperceptible
  • • Plan for potential quality degradation with speed increases above 115%

⚠️ Important Considerations

  • • Audio pitch will change unless separately corrected
  • • Large speed changes may affect motion smoothness
  • • Consider your audience's perception of speed changes
  • • Test on a sample clip before applying to entire project

🎬 Broadcast Tips

  • • Use for meeting broadcast timing requirements
  • • Essential for commercial break planning
  • • Helps with international format conversions
  • • Save calculations for future reference with similar content

Troubleshooting

Very high speed percentage (above 200%)

Cause: Target length is much shorter than clip length

Solution: Double-check your time inputs - you may have swapped clip and target lengths

Speed shows as exactly 100%

Cause: Clip length and target length are identical

Solution: Verify your target length is different from source, or no change is needed

Results seem incorrect

Cause: Frame rate mismatch or timecode entry error

Solution: Ensure frame rate matches your project and verify all timecode fields are correctly filled

Related Calculators

Speed Change Calculator

Calculate speed percentage for frame rate conversions

Timecode Calculator

Available in CineMath app

← Speed Change CalculatorTarget Bitrate Calculator (in App) →