# MP3TAG Maths

**URL:** https://community.mp3tag.de/t/mp3tag-maths/7887
**Category:** Support
**Created:** [February 4, 2009, 8:07pm UTC](https://community.mp3tag.de/t/mp3tag-maths/7887 "2009-02-04T20:07:30Z")
**Posts on this page:** 1
**Showing post:** 1

<div class="post-metadata">

### Author: ![jonhayre](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/j/aca169/32.png) [@jonhayre](https://community.mp3tag.de/u/jonhayre)
#### Post date: [February 4, 2009, 8:07pm UTC](https://community.mp3tag.de/t/mp3tag-maths/7887/1 "2009-02-04T20:07:30Z")

</div>

I have a formula that i would like to use with mp3 tag, but i can't seem to get it to work..

I am a DJ and keep my files tagged nicely with mp3 tag and it does a brill job.. what i want to do tho is to calculate a percentage increase/decrease from a bpm field (handy when mixing)..

the formula in excel is (130-%bpm%)/%bpm% then changed to a percentage (\*100) (i use mix meister bpm analyser to calculate the bpm then this will tell me the percentage i have to increase the track to mix at 130bpm - lazy i am !)

i can't get this to work in mp3 tag as i think it rounds numbers or removes decimal point

i want it to create a new field or place it in the comment field as something like +1.55%

anyone help pls ?

Jon.

---

_[View the full topic](https://community.mp3tag.de/t/mp3tag-maths/7887)._