The formula
We count how many AI calls each developer makes in a month, then cost each call: the text read (cheaper for the part reused from cache) plus the text written. The payoff side is simpler - the hours the tool saves × what an hour of that developer's time is worth.
Questions
How much does an AI coding tool cost per developer?
Tens of dollars a month for normal use, more for heavy use. Reusing the codebase from cache brings that down a lot.
Is a flat subscription or pay-as-you-go cheaper?
For light, steady use a flat monthly subscription is usually simpler and cheaper. For heavy use it depends on volume - work out the pay-as-you-go cost here and compare it.
How much faster does it need to make me to be worth it?
Surprisingly little - developer time is expensive, so even a 1–3% boost usually covers the cost. The calculator shows your exact break-even.