Answers.Body: <p>(115bpm / 120 bpm) * 100 = 95.83% (approx, to 2 decimal places)</p>
  
  <p>Speed change percentages are always confusing.</p>
  
  <p><a href="https://support.apple.com/kb/PH12643?locale=en_US&amp;viewlocale=en_US" rel="nofollow noreferrer">Final cut expresses speed changes as</a>:</p>
  
  <blockquote>
    <p>If you change the speed to 50 percent, your clip becomes twice as long
    [...] 
    If you change the speed to 200 percent, the clip becomes half as
    long</p>
  </blockquote>
  
  <p>So if you go from 120 bpm to 115 (a slower tempo), you are looking for a longer clip, so your percentage should be lower than 100%.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-07-01T08:05:42.007Z
Answers.Text: That should be `(115bpm / 120 bpm)`
Answers.UserDisplayName: Gyan
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-07-01T08:07:41.423Z
Answers.Text: gah... told you it was confusing :) thanks
Answers.UserDisplayName: tomh
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-06-30T20:35:23.693Z
Answers.LastActivityDate: 2019-07-01T08:07:28.593Z
Answers.LastEditDate: 2019-07-01T08:07:28.593Z
Answers.UserDisplayName: tomh
Body: <p>scenario:</p>
  
  <p>I have video matched with audio (song).</p>
  
  <p>I slow the audio (song) down (eg from 120 bpm to 115bpm ie, I know exactly how much slower the new audio is than the original video)</p>
  
  <p>How do I calculate how much to slow down my video by (in Final Cut I have the option of slowing down from 100% speed right down to 1%) so it matches the slow(er) audio?</p>
  
  <p>thanks.</p>
  
Tags: <video><video-editor><audio>
Title: Formula / Calculate how much to slow video down to match audio?
UserDisplayName: T.McL
ThreadText: # Formula / Calculate how much to slow video down to match audio?
  
  (Asked by: username_0 on 2019-06-30)
  
  scenario:
  
  I have video matched with audio (song).
  
  I slow the audio (song) down (eg from 120 bpm to 115bpm ie, I know exactly how much slower the new audio is than the original video)
  
  How do I calculate how much to slow down my video by (in Final Cut I have the option of slowing down from 100% speed right down to 1%) so it matches the slow(er) audio?
  
  thanks.
  
  **Tags:** video, video-editor, audio
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2019-06-30. Score: 0 | Accepted answer
  
  (115bpm / 120 bpm) \* 100 = 95.83% (approx, to 2 decimal places)
  
  Speed change percentages are always confusing.
  
  [Final cut expresses speed changes as](https://support.apple.com/kb/PH12643?locale=en_US&viewlocale=en_US):
  
  > If you change the speed to 50 percent, your clip becomes twice as long
  > [...]
  > If you change the speed to 200 percent, the clip becomes half as
  > long
  
  So if you go from 120 bpm to 115 (a slower tempo), you are looking for a longer clip, so your percentage should be lower than 100%.
  
  > **Comments:**
  > **username_2**: That should be `(115bpm / 120 bpm)`  
  > **username_1**: gah... told you it was confusing :) thanks  
  
  ---
  
  