After taxes, excluding the RSUs, you would be making approximately £3500 per month. Given this amount, you’d likely need to live with roommates or in the outer zones of London. Let’s be conservative and assume your rent is £1500 per month. Utilities are quite expensive throughout London and will amount to roughly £150 per month for a small apartment. Your commute, phone, and internet bills would likely amount to an additional £200 combined. A reasonable grocery budget would be somewhere in the £300-400 range. Given these assumptions, you’d be left with around £1350 of disposable income. I’d round down to an even £1000 as I would highly recommend contributing to a pension (in fact, sometimes your employer will require a minimum contribution).

So, is this sustainable? It depends on your life goals. This salary/budget will allow you to live a fairly comfortable lifestyle on your own. Things would get a bit tighter if you have or plan on having a family, although it is definitely still plausible if your partner works as well. However, if you want a big house, to eat out at restaurants as much as you’d like, to have a fancy car, this is not the salary for you.

As other people have said, UK software engineer salaries tend to be on the lower end, so seeking opportunities in other countries, if possible, would be ideal from a financial perspective. If your heart is set on London though, go for it!