Hi, I’m Andrew. I built this because FIF tax made no sense to me either.

A couple of years back I had a handful of overseas shares and a looming IR3. Even with an accounting degree behind me, the FIF rules read like a foreign language, and the spreadsheet I cobbled together took a whole weekend and still felt wrong.

So I built the thing I wished existed: a calculator that does FDR and the comparative-value method, picks the lower one, and shows its working against the IR461 examples. In plain English, for free.

It follows IRD’s published guidance and the Income Tax Act 2007.

• It runs entirely in your browser.
• There’s no account to make and no server collecting your portfolio. Your numbers never leave this device.
• Chartered accountant Jack Smith reviewed the calculations and the guides (June 2026), so the figures hold up.

I keep it accurate because I use it myself. If something looks off, or a broker changes its export and an import breaks, I genuinely want to hear about it. That feedback is what keeps the tool honest.