Now that Revolut got their UK banking license, I wanted to see if it would make sense to use them for the purposes of opening a savings account. They have fairly competitive rates and the fact that they pay out interest daily is quite a nice flexibility for shorter term holdings (most banks pay interest only every month or even months and sometimes you will not accrue any if you take it out before the full period).

One interesting factor to consider is that Revolut has a tiered interest rate, which depends on which Revolut plan you pay for. For those unfamiliar, the Revolut tiers give you access to nicer cards (stainless steel or even platinum coated), reduce costs (e.g., forex on weekend, and reducing/removing foreign transfer fees), and a multitude of 3rd party deals (e.g., NordVPN, ClassPass, WeWork, etc..).

To me that meant that this is an obvious optimization case, where I wanted to compute which amounts you would need to have in your savings account to both break even, and to justify paying for the next tier up.

I wanted to approach this purely from the perspective of the savings account, so to simplify the solution I treat the value of everything else the Revolut plans as 0.

Solving it is as simple as calculating the daily accumulating interest rate, and comparing the expected returns (minus the effective tax rate) versus the Revolut plan costs.

My first solution was a hand-written Rust implementation (because I still love Rust) that prints a nice ascii table.

But I realized I knew a few people that might be interested in the break even points, so I used OpenCode + GLM 5.1 (my current agentic setup for personal projects, after I recently cancelled my Anthropic subscription), and told it to make me a single HTML file version with graphs and inputs to help people figure out which plan makes the most sense for everyone.

Disclaimer that the interest rates and tax rates are only correct as of the current time of writing, and this is not financial advice.

You can check out the tool and figure out for yourself here Revolut UK Savings Plan Comparator.