What "chance of success" means

Chance of success is the share of 5,000 simulated retirements in which your money never ran out before your planning age.

You'll see two numbers. The paycheck is pinned to a 90% chance — the highest spending that survived in 9 of 10 runs. The line "X% chance your $__/mo spending is covered" is different: it's the probability that the spending you entered, not the paycheck, lasts to 95. If you spend less than your paycheck, that number is above 90%; if more, below.

One nuance: a run counts as a success even if the spending guardrail had to trim discretionary spending after a bad year — the money lasted, but not every year was fully funded. MangoDime also tracks how often spending was never cut; that figure is reported separately where it appears.

The dashboard badge translates the percentage: On track at 90% or above, Mostly on track from 75%, At risk from 50%, Needs attention below that.