The best FIRE calculator depends on whether you are building savings, checking retirement withdrawals, or deciding to work less. Start with FireFolio for an editable path to financial independence, FI Calc or FIRECalc for historical retirement scenarios, and WalletBurst for Coast FIRE. Consider ProjectionLab or Boldin when you need a broader household plan. The six choices below serve different jobs; their order is not a score.
How we chose these calculators
We selected tools with a distinct planning use, a public explanation of their approach, and enough visible information to understand where to start. This is an editorial comparison of public tools and provider documentation checked October 21, 2026, not a controlled accuracy benchmark or a hands-on review of every paid feature. FireFolio publishes this guide and is one of the products included. External links are direct, without affiliate tracking.
Before comparing results, match spending, dollar basis, retirement duration, contributions, and income timing. A historical success percentage, a simulated success percentage, and a constant-return projection answer different questions. A larger projected balance does not make a calculator better.
| Calculator | Useful starting question | Access / main boundary |
|---|---|---|
| FireFolio | How could saving and spending change my FIRE timeline? | Free public planner; account for saving online. Simplified assumptions. |
| FI Calc | How did a withdrawal approach fare in historical periods? | Public simulator; historical coverage is not a forecast. |
| FIRECalc | Would this spending have exhausted my portfolio in past periods? | Public calculator; inspect its spending and portfolio defaults. |
| WalletBurst | Could I stop retirement contributions and retire later? | Public Coast tool; current bills still need funding. |
| ProjectionLab | How do life events and cash flows fit together? | Basic and paid tiers; verify which features your tier includes. |
| Boldin | How do accounts, income, and taxes fit a retirement plan? | Free Basic and paid PlannerPlus; advanced features depend on tier. |
1. FireFolio: for connecting today’s choices to a FIRE timeline
Use the public planner to connect invested assets, monthly contributions, and annual retirement spending. Its simple mode projects accumulation at a constant return after inflation and estimates a retirement target with simulated return paths. You can change the retirement horizon, return assumptions, and later income, then compare scenarios. Public exploration does not require an account; saving plans online does.
Best fit: someone who wants to understand which inputs move the date and then explore a related household decision. Use Life scenarios for a career break or pay cut. The simple planner is not an account-by-account tax engine, and its simulated target is not a guarantee of retirement safety.
2. FI Calc: for comparing retirement withdrawal strategies
FI Calc evaluates retirement plans against historical data. Its public interface includes a withdrawal-strategy selector, asset allocation, additional income, and extra withdrawals. It is a useful choice when your question is how spending would have behaved after retirement, rather than how quickly contributions might reach a target.
Look at spending variability as well as portfolio survival. A strategy can preserve a balance by allowing spending to fall below what you need. Historical results describe the periods and rules tested; they do not establish the probability of your future outcome.
Sources: FI Calc · Historical retirement simulator ↗ (opens in a new tab)
3. FIRECalc: for a historical second opinion
FIRECalc begins with spending, portfolio value, and retirement length, then compares historical starting periods. Additional controls address income, spending models, and portfolio assumptions. It is a useful second opinion when you want to see how the same plan would have faced different market histories.
Inspect the defaults before interpreting the result. Match your intended horizon and portfolio assumptions, and distinguish a fixed spending plan from a flexible one. Historical coverage cannot include economic conditions that have not yet happened.
Sources: FIRECalc · Retirement calculator and methodology ↗ (opens in a new tab)
4. WalletBurst: for the Coast FIRE question
WalletBurst’s Coast FIRE tool connects your age, retirement age, invested assets, spending, contributions, growth, inflation, and withdrawal assumption. Choose it when you want to explore whether existing investments could grow toward a later retirement target without more contributions.
Reaching a Coast threshold does not mean you can stop earning. Your present living costs still need a source of income while the portfolio stays invested. Test less favorable growth assumptions before treating the threshold as a career decision.
Sources: WalletBurst · Coast FIRE calculator ↗ (opens in a new tab)
5. ProjectionLab: for a broader picture of life and cash flow
ProjectionLab is worth exploring when you want a visual financial plan with simulation and more detailed life-event modeling. Its pricing page lists a free Basic tier and paid tiers; cash-flow projections, tax features, and comparison capabilities have tier-specific availability.
Start with the public feature comparison and confirm that the feature you need is included before subscribing. Extra detail helps only if you can maintain the inputs and understand the model. We have not independently audited its tax calculations or tested every paid workflow.
Sources: ProjectionLab · Pricing and feature comparison ↗ (opens in a new tab)
6. Boldin: for organizing a detailed retirement plan
Boldin offers a free Basic plan and paid PlannerPlus, with a provider comparison covering planning and advanced analysis. Consider it when retirement involves several accounts, income sources, and tax questions that a single target number cannot organize.
Check the current feature table and subscription terms rather than assuming that every advertised capability is free. Our recommendation is about the planning use case, not an independent validation of its tax or investment outputs.
Sources: Boldin · Pricing and plan features ↗ (opens in a new tab)
Read the original.
- FI Calc · Historical retirement simulator ↗ (opens in a new tab)
Public configuration includes withdrawal strategies, extra income, extra withdrawals, and historical simulations. Reviewed October 21, 2026.
- FIRECalc · Retirement calculator and methodology ↗ (opens in a new tab)
Historical starting-period comparisons and controls for spending, income, and portfolio assumptions. Reviewed October 21, 2026.
- WalletBurst · Coast FIRE calculator ↗ (opens in a new tab)
Coast threshold explanation with growth, inflation, contributions, and retirement-age inputs. Reviewed October 21, 2026.
- ProjectionLab · Pricing and feature comparison ↗ (opens in a new tab)
Provider lists Basic and paid plans with different planning capabilities. Check the current tier before choosing a feature. Reviewed October 21, 2026.
- Boldin · Pricing and plan features ↗ (opens in a new tab)
Provider comparison of Basic, PlannerPlus, and advisory offerings. Reviewed October 21, 2026; purchase terms can change.
The FIRE application and exercises are FireFolio’s original interpretation. No affiliation or endorsement is implied. Sources checked October 21, 2026. Educational material, not individualized investment advice.