A real answer based on your savings rate, current age and target lifestyle.
Find your real retirement timeline
Your retirement age under different conditions
The most widely-used retirement target is the "25x rule" — multiply your desired annual retirement spending by 25 to find your target nest egg. This comes from the 4% safe withdrawal rate: a portfolio of that size can theoretically sustain 4% annual withdrawals (adjusted for inflation) for 30+ years without running out.
The biggest lever in this calculation isn't your income — it's your savings rate and how early you start. Someone saving 15% of income from age 25 will often retire years earlier than someone saving 25% starting at age 40, purely due to compounding's relationship with time.
Don't forget Social Security or pension income in your real planning — this calculator shows the nest egg needed to fully self-fund retirement, but guaranteed income sources reduce how much you personally need to have saved.