When is it okay to give myself a raise as a founder?

Tie a raise to what the business can carry, not to how long you have gone underpaid. A sensible trigger is when steady revenue or a fresh round means your salary is a small, predictable line that will not shorten runway in a way that scares you. Move toward a number that covers a normal life in your city rather than a lavish one, so you stop quietly subsidising the company from your savings. Talk to your co-founders, and to your board if you have raised, so the change is on the record rather than a secret. Step it up gradually instead of in one jump. Keep in mind that higher salary is taxed as income, and slabs and rules change, so confirm the take-home with a CA. The point is to make brave decisions from a place of stability, not to reward yourself.