FIRECalc vs Flexible Retirement Planner

FIRECalc is a free web calculator for assessing whether savings, planned spending, and other resources could sustain retirement. It tests plans against historical market conditions beginning in 1871 and reports how often the portfolio would have remained funded for the selected term across historical starting years. Users can include Social Security, pensions, and other income or spending adjustments. Spending options include inflation-adjusted constant amounts, Bernicke's Reality Retirement Plan, and a percentage of the remaining portfolio. Portfolio settings allow historical investment portfolios, fees, and consistent or random returns. Planning inputs can include a future retirement date, annual contributions before retirement, and future lump-sum changes. Defaults are a 75% stock-index and 25% bond-fund portfolio, a 0.18% fund fee, and inflation-adjusted spending over 30 years. FIRECalc says it cannot predict future returns and does not provide tax planning. The homepage reports data through January 1, 2026, updated April 17, 2026. It says it does not store financial entries; temporary spreadsheet and graphic files are deleted after about 15 minutes.

Flexible Retirement Planner models retirement outcomes with Monte Carlo simulation and reports the probability that a plan succeeds. It runs 10,000 simulated paths spanning savings accumulation and retirement spending. Users can compare Stable, Flexible, and Conservative spending policies, test different assumptions, and use sensitivity analysis to see which inputs affect results most. The standalone version lets users save inputs and maintain multiple what-if scenarios, and it works offline. The planner includes income and savings growth projections, withdrawal planning, detailed tax modeling, and Social Security modeling. Standalone downloads are provided for Windows and Mac/Linux; the Windows version does not require Java. The planner is free for individual non-commercial use, and educators and trainers may use it for educational purposes. A voluntary contribution of any amount unlocks a personal-use license key. Commercial use, including by financial planners, is not authorized or supported. Its maker, Random Walk Ventures LLC, created it in 2006.