RetireCalcs vs Vanguard Retirement Nest Egg: Monte Carlo Comparison
Vanguard's free Retirement Nest Egg calculator runs Monte Carlo simulations on your portfolio to estimate the probability of running out of money. RetireCalcs uses deterministic projections (specific return assumptions, specific scenarios). Both have value — Monte Carlo for probability, deterministic for understanding what drives the answer.
Vanguard Retirement Nest Egg pros
- Monte Carlo simulation runs 100,000+ randomized market paths — gives a true probability of success
- No account, no login required for the Nest Egg calculator (one of the few Vanguard tools that works for non-customers)
- Output is intuitive: "your portfolio has an 87% chance of lasting 30 years"
- Underlying capital markets assumptions are based on Vanguard's 10-year forecasting model (rigorous methodology)
- Free — Vanguard does not gate this tool
Vanguard Retirement Nest Egg cons
- Limited inputs — only portfolio size, withdrawal rate, retirement length, and asset mix. No tax modeling, no Social Security, no Roth conversion logic
- Single calculator, no broader scenario suite (no FIRE math, no RMD projection, no 401(k)-by-age targets)
- Output is probabilistic, which can be hard to act on (87% success → what should I change to make it 95%?)
- No save/share function — every visit is a fresh entry
- UI has not changed in years and is dense for first-time users
Where RetireCalcs is better
- Broader scenario coverage — 401(k) by age, FIRE math, Social Security claim timing, RMD rules, Roth conversion strategy
- Deterministic projections that show the math driving the answer (not just a probability)
- Step-by-step guides paired with each calculator
- Mobile-first UI, faster page loads
- Easy "what if" comparisons: change one input, see the change, repeat
Use Vanguard Retirement Nest Egg when
When you specifically want a Monte Carlo probability-of-success number for your retirement portfolio. The simulation methodology is rigorous and the output is genuinely useful as a sanity check.
Use RetireCalcs when
For everything else: How much do I need to retire, what is my FIRE number, when should I claim Social Security, should I convert traditional to Roth this year, what are my RMDs going to look like at 75. Most retirement planning questions are not "what is my probability of success" — they are "what change should I make to improve my plan."