One number, updated as you go. Built in two minutes from your salary and your rent.
Take-home, after tax. A rough number is fine.
The one number everybody knows exactly. It decides most of your budget, so guessing it just wastes your time later.
Essentials come from your rent, not a rule of thumb. One slider changes how the rest splits.
One number to watch. Log what you spend and it moves.
Up to a minute. You approve it in your bank's own app, then land back here.