UK VAT Calculation change

[molevid]

Hello,

I have now been running my database with no great issues for nearly a year now. I now have a problem which I am sure is easy to fix however have been unable to figure out.

We had a VAT (tax) change here starting 1st January 2010, I could change the calculation no problem however it changes all the database records so when we look back at old invoices it has the incorrect VAT on it.

Can somone advise how to calculate the VAT field @ 15% for invoices raised before 1st Jan 2010 and 17.5% for invoices rasied after 1st Jan 2010? Currenlty the VAT calculation is: nett amount * .175

I have tried to use the "if" function when making the VAT calculatuion however this either calculates at one rate or does not calculate at all. FYI I have tried the following:-

If (invoice date < 1/1/2010, Net amount * .175) or If (invoice date < 1/1/2010, Net amount * .15)

Any help here would be appreciated.

Thanks

[comment]

See if this helps:

http://forum-en.filemaker.com/t5/Using-FileMaker-Pro/VAT-changing-back-to-17-5/td-p/44186

[IdealData]

however it changes all the database records so when we look back at old invoices it has the incorrect VAT on it.

The fundamental mistake here is that you have used a hard coded approached. You need to record the prevailing VAT rate in a separate field (VAT rate) on each invoice and use the calculation:

Nett amount * VAT rate

Edited March 10, 2010 by Guest