FIRE Calculator

Like most FIRE people, I'm a bit of an Excel geek. I work extensively with the platform and I also track my finances every month on it.

I've designed a spreadsheet which lets you understand when you can FIRE. As you will not be able to take a private pension until aged 57, if you decide to retire before this date you will need a "bridge" account. I recommend a S&S ISA on a platform like Vanguard, but obviously do your own research on what works for you.

You can access it on GoogleSheets here

How to use:

The only cells you need to alter are in bright yellow, you can then play around with the fire date to see how much more you need in your "bridge" account.

1. Enter you year of birth in cell G1

2. Enter the expected growth in cell G2 (rule of thumb historically is 7%

3. Enter how much money you will need to live off during your "bridge" period in cell G6. This is between when you FIRE and when you can take your private pension (57). Factor in whether you will have any mortgage costs by then and childcare etc

4. Enter your current "bridge" pot in cell G9. Include how much you currently have in long term savings, and any other assets.

5. Enter your current pension pot (cell G15) and how much you plan on contributing per year (G17)

The number in red under "needed" indicates that I am going to fall short of my target. I either need to lower my "estimate per year", increase my current pot, or alter my "Age FIRE".

6. To alter your "Age FIRE", click the drop down (G7) and choose a new age to FIRE.

Below, I have chosen 51 rather than 50, as this is the soonest I can FIRE using the current pot and estimate per year required figures. However, you may notice that by altering this, my pension has breached the £1m limit (due to me having an extra year before I FIRE, contributing to my pension).

6. To alter your pension, so it doesn't breach the lifetime allowance. Reduce the contributions per year (G17)

Overall, this spreadsheet is very flexible and gives you a good indication about what is possible given your current situation, savings & pension pots, as well as expectations about what kind of income to expect later on in life.

Any feedback just let me know! There are a few niggles like assuming the overall pension pot is spread over 24 years whereas in real life there will be a 25% tax free element, the Pension Lifetime Allowance will likely increase in the future also the pension age may well change in the future also.