With this simple app you can quickly find the answer.
On the 4th January the standard rate of VAT in the UK increased from 17.5 per cent to 20 per cent.
Enter in the current price and in a flash it will show you what the price would have been at the old VAT rate, and the price excluding VAT. You can enter either the new price, the old price or price excluding VAT to calculate the other prices.
Note: this application is for fun and education purposes only; it does not have any warranties or guarantees, nor is it endorsed by HMRC.