Building the Beta version of the FIFO Profit Calculator

Website: https://uposcar.com/tools/pnl-fifo-calculator

Why I Built It

So there I was, escaping the rain to move to sunny Spain. Until I started preparing to move, I never had to worry about selling my shares and stocks because we have ISA accounts in the UK. Any profit from shares, or even interest from savings, is protected from tax. And then you don't even have to worry about completing a self-assessment.

In Spain, however, even if you have an ISA account, when you profit from selling (or disposing of) your assets, you trigger a taxable event, and you've got to pay (unless you're under some exemption like the Beckham Law). On top of that, when working out how much tax you have to pay, you can't just use the same method as in the UK.

The UK uses a pooling method with weighted averages to calculate the cost basis when working out your gains. Spain, however, uses the FIFO (First-In-First-Out) method for calculating gains.

I wanted to track my PnL (profit and loss) so I could work out how much tax I needed to put aside whenever I sold any shares. I needed a really simple tool. So I built one!

Limitations of the tool

While it doesn't work out taxes, the tool is free and calculates the PnL for one stock at a time. If you've got a tonne of trades going across a lot of stocks, well, it's probably too simple for your needs. However, if people are interested, I'll consider developing that tool to have more features.

It's not mobile-friendly, yet, but I look forward to working on that soon.

Remember to always seek advice from a professional about taxes if in doubt.

Now you can find the tool here:

https://uposcar.com/tools/pnl-fifo-calculator