Not the same as “available balance”
Banks show cash that still has obligations attached. Safe-to-spend is a planning number: cash you can use without breaking promises you care about.
What goes into it
Upcoming bills you believe are accurate, savings targets you do not want to steal from, and sometimes a conservative buffer for irregular expenses.
It should be explainable in one sentence. If you cannot explain it, the number is not trustworthy yet.
Why it lowers anxiety
Anxiety spikes when decisions compete with unknowns. A single spendable signal collapses many unknowns into one check before you tap pay.