Best Free Retirement Calculator in 2026
Retirement calculators range from simple spreadsheet formulas to institutional-grade Monte Carlo simulations. The difference matters: a calculator that assumes normally distributed returns and uses historical averages will give you a very different answer than one that models fat tails and uses forward-looking assumptions.
Comparison table
| Tool | Monte Carlo | Fwd-looking | Fat tails | BTC | SWR grid |
|---|---|---|---|---|---|
| Portfolio Lab | ✓ | ✓ | ✓ | ✓ | ✓ |
| cFIREsim | ✓ | ✗ | ✗ | ✗ | ~ |
| FICalc | ✗ | ✗ | ✗ | ✗ | ✓ |
| FireCalc | ✓ | ✗ | ✗ | ✗ | ✗ |
| Fidelity Planner | ✓ | ~ | ✗ | ✗ | ✗ |
1. Portfolio Lab
Monte Carlo simulation with 10,000 paths using Cornish-Fisher adjustment for skewness and kurtosis. Uses J.P. Morgan 2026 forward-looking assumptions instead of historical returns. Full withdrawal rate grid across 13 rates and 6 time horizons. Bitcoin as a built-in asset class.
Best for: Anyone who wants their retirement simulation based on where markets are going, not where they have been. FIRE planners who need to model 40-50 year horizons. Investors considering Bitcoin in their retirement portfolio.
Limitations: Newer platform. No social security modelling. No tax-bracket analysis.
2. cFIREsim
Popular in the FIRE community. Uses historical market data to simulate thousands of overlapping retirement periods. Shows survival rates across different starting dates.
Best for: FIRE planners who want to see how their plan would have survived every historical starting year. Simple, focused interface.
Limitations: Historical returns only (no forward-looking). Assumes normal distribution. US-centric. No Bitcoin. No custom asset class support.
3. FICalc
Clean, focused withdrawal rate calculator. Tests different withdrawal strategies (constant dollar, percent of portfolio, guardrails). Based entirely on historical US data.
Best for: Comparing withdrawal strategies side by side. Clean UX. Understanding how guardrails affect portfolio longevity.
Limitations: Not Monte Carlo (historical periods only). No forward-looking assumptions. Limited asset class options. No Bitcoin.
4. FireCalc
One of the original retirement calculators. Monte Carlo using historical US data going back to 1871. Functional but dated interface.
Best for: Long historical data. Testing against the full range of US market history including the Great Depression and 1970s stagflation.
Limitations: Dated interface. Normal distribution assumption. US-only. No Bitcoin. No forward-looking option.
5. Fidelity Retirement Planner
Comprehensive financial planning tool with Monte Carlo simulation, income modelling, and social security estimates. Requires a Fidelity account.
Best for: Fidelity customers who want integrated planning across all their accounts. Income modelling and spending categories.
Limitations: Requires Fidelity account. Proprietary assumptions (not transparent). No Bitcoin. No custom optimization methods.
What actually matters in a retirement calculator
- Forward-looking assumptions. Historical US returns include a 40-year bond bull market. If the next 30 years look different, your retirement plan needs to account for that.
- Fat-tail modelling. Real markets have crashes that are more severe and frequent than a normal distribution predicts. Cornish-Fisher adjustment captures this.
- Withdrawal rate grid. Testing a single withdrawal rate gives you one data point. A full grid across rates and time horizons shows where the safe zone actually is.
- Transparency. If you cannot see the assumptions, you cannot trust the output.
Test your retirement plan
10,000 Monte Carlo simulations. J.P. Morgan assumptions. Free.