I mainly write custom windows programs to help automate imaging workflow for clients but occasionally I write the odd useful utility program.
vatcalc 2.0 allows you to change any of the values in the boxes (just press the tab key to the box you require and enter a value) vatcalc will then update the other variables allowing you for instance to work out the exclusive and vat values when entering a retail vat inclusive price – handy for those vat returns.
You can buy vatcalc from the shop section of this website.