Please note: To be able to download your finished calculations from this site, you will need cookies enabled in your browser.

To enable cookies in your browser, go to or click on the following:

Tools --> Internet Options --> Privacy --> Advanced

To access the tools menu in Windows 7 / Vista / IE9, click on the tools icon on the top right of the browser window.

When in the advanced section:

"Override automatic cookie handling" should be ticked.

"Always allow cookie sessions" should be ticked.

"1st Party cookies" should be set to accept.

"3rd Party cookies" should be set to accept.

When this is done click OK, and then OK again. Before the second OK and if the button is highlighted, click Apply.

You should now be able to use the on-line calculator without problems.