Automatic tax calculation.

I can't see if this is already in existence, but I want to be able to enter a price (eg: £100) i've set the UK VAT to 20%

so the end price is £80 and £20 Tax.

Is this possible, instead of having to take 20% off each price before entering it....It's a bit time consuming.

My Product Manager extension allows you to enter prices this way. However, I'm not aware of any extension that only offers that by itself.

Thank you for your reply, I tried the demo and can't see how it does this?

You'll want to click "Toggle Columns" and then select "Price (w/Tax)" and from there you can see all you have to do is edit the price w/tax and it will automatically update the price and visa versa. You can set the default tax rate in the settings.

There is a brand new extension that is created exacly for that purpose. See this: Price Input Helper: http://forum.opencart.com/viewtopic.php?f=123&t=68745
Regards,
Guntis