About this calculator
A retirement calculator projects a nest egg at a target retirement age and tells you how much income that egg will produce. It combines two phases of math: accumulation (compounding contributions until retirement) and decumulation (drawing income while the remaining balance still grows).
The 4% rule, briefly
The widely-cited "4% safe withdrawal rate" comes from the Trinity Study: a retirement portfolio of 60% stocks/40% bonds that withdraws 4% of the initial balance (adjusted for inflation each year) survived 30+ years in nearly every 30-year period in US history. At 5% withdrawal, a non-trivial number of historical periods exhausted the portfolio. At 3%, almost none did — but you live more frugally.
The single biggest variable
Years saving compound far more than contribution amount. Saving $500/month from age 25 to 65 at 7% returns produces about $1.2M. Saving $1,500/month from age 45 to 65 at the same rate produces about $790k — three times the contribution rate, two-thirds the result. Start early.
Sequence of returns risk
A 30% market drop in year 1 of retirement is catastrophic; the same drop 10 years in is recoverable. This calculator doesn't model sequence risk — it assumes steady returns. In reality, planning for a sustained downturn in the first 5 years (e.g., 60% equities glide-path-ing down to 40% by retirement, or holding 2-3 years of expenses in bonds) is what separates resilient plans from fragile ones.