Financial Independence Spreadsheet: 5 Options Ranked for 2026

Quick answer. The five financial independence spreadsheets worth considering in 2026: Mad Fientist’s free FI Spreadsheet (deep but Excel-first), the Bogleheads/Reddit shared FI workbook (community-built), ProjectionLab as a SaaS alternative ($109/yr or $1,199 lifetime), Aspire Budgeting (free, envelope-focused, weak on FI projection), and our Financial Planning Spreadsheet ($39 one-time, integrated FI projection plus budgeting and net worth). Pick based on what you weight most: depth, support, or cost.

In this article

• The five options compared on FI projection capability, methodology depth, support, and cost
• What FI tracking actually requires vs. what’s nice-to-have
• A side-by-side feature matrix
• Which option fits which user
• A worked example: same person, different tools
• Common shortcomings across the field
• How to migrate between them

A serious FI tracker has to do one thing well: project how many years of work you have left at your current saving rate, and update that projection live as your savings rate or balance changes. Everything else (charts, asset allocation, withdrawal modeling) is helpful but secondary. This post compares the five most-used options against that core requirement and the surrounding nice-to-haves.

What FI tracking requires

Three calculations, in order of priority.

1. Years to FI.

Years to FI = log((FI Number * r + Spending) / (Current * r + Spending)) / log(1 + r)

Where r is real return, Current is current invested balance, Spending is annual spending (which doubles as the FI target divisor at 25x), and FI Number is 25 times annual spending. If that formula looks intimidating, it’s because the math behind FI is annuity math, not simple compounding.

Most spreadsheets simplify by either using a closed-form approximation or running a year-by-year iteration in a column. Both work; the iteration version is easier to read.

2. Savings rate.

Savings rate = (Total annual savings) / (Take-home income)

Or some people use gross income; either is fine as long as you’re consistent. Most FI math is more sensitive to savings rate than to absolute spending; a 50 percent savings rate produces FI in around 17 years regardless of whether you earn $50K or $500K.

3. Current FI ratio.

FI ratio = (Current invested balance) / (FI Number)

How far you are. 0.4 means you’re 40 percent of the way to your FI number.

These three numbers are the dashboard. Everything else is supporting detail.

The five options compared

Option 1: Mad Fientist’s FI Spreadsheet (free, Excel-first)

The original. Mad Fientist’s FI Laboratory included a free downloadable spreadsheet that became the template for the genre.

What it does well

• Deep methodology. Calculates years to FI, projected balance, and net worth over time with serious math.
• Includes scenarios (different savings rates, different return assumptions).
• Free.
• Citation rich; mentioned in dozens of FI blogs.

Limitations

• Excel-first. Conversion to Sheets breaks some formulas.
• Last updated several years ago; methodology is solid but UX is dated.
• Single methodology baked in (specific savings rate framing).
• No support; community discussion happens on the FI forums.
• Doesn’t integrate budget tracking.

Best for people who want the original FI spreadsheet methodology and don’t mind Excel.

Option 2: Bogleheads/Reddit FI workbook (free, community)

Several user-built workbooks circulate on r/financialindependence and the Bogleheads forum. The most-cited is a multi-tab workbook that combines net worth tracking, savings rate calculation, and FI projection.

What it does well

• Built by deeply engaged FI practitioners.
• Often handles edge cases (multiple account types, employer match, taxable vs tax-deferred withdrawal sequence).
• Free, with active forum discussion.

Limitations

• Quality varies by author.
• No central support; updates depend on the original creator’s time.
• Often heavily personalized to the creator’s situation; requires customization.
• Documentation lives in forum threads, which can be hard to search.

Best for spreadsheet-comfortable users who enjoy customizing and want a community-vetted starting point.

Option 3: ProjectionLab (SaaS, $109/yr or $1,199 lifetime)

Not a spreadsheet, but the most-cited alternative for serious FI planning.

What it does well

• Best-in-class UX for retirement and FI projection.
• Monte Carlo simulation, Sankey diagrams, scenario branching.
• Multi-country tax modeling (US, CA, UK, AU, DE, NL).
• Active development, regular feature updates.

Limitations

• Not a spreadsheet. Closed math; you can’t audit the formulas.
• Recurring or large lifetime cost.
• Data syncs via Firebase; not strictly offline.
• No spreadsheet export if you want to leave.

Best for users who value Monte Carlo and visual scenarios, are comfortable with the cost, and don’t care about formula transparency. See ProjectionLab Alternative for the full comparison.

Option 4: Aspire Budgeting (free, donation-funded)

Aspire is a Google Sheets envelope budgeting template. It includes basic FI math but the focus is monthly budgeting.

What it does well

• Free, privacy-clean, donation-funded.
• Strong envelope/zero-based methodology.
• Active Reddit community (r/aspirebudgeting).

Limitations

• FI projection is light; main focus is monthly budgeting.
• Steep onboarding curve.
• Single methodology (envelope) may not fit all users.
• No formal support or update SLA.

Best for users primarily focused on monthly budgeting with FI as a secondary interest. See Aspire Budgeting Alternative for the budget comparison.

Option 5: FinancialAha Financial Planning Spreadsheet ($39 one-time)

Our entry. Integrates FI projection with budget tracking, net worth, retirement, and goals in a single workbook.

What it does well

• Google Sheets native, mobile-friendly.
• One-time cost.
• Connected to the rest of our template suite (Net Worth Tracker, Annual Tax Planner, Retirement Projections).
• Active maintenance with email updates.
• Email support.
• Country-agnostic (no hard-coded tax assumptions).

Limitations

• Deterministic projection only; no Monte Carlo. (For Monte Carlo, pair with ProjectionLab as a one-time stress test.)
• Newer than Mad Fientist’s; less established in the FI community.
• $39 vs free options.

Best for users who want maintained software, integrated budget plus FI tracking, and a one-time cost.

Side-by-side feature matrix

A worked example: same person, five tools

Marcus is 32, $180K invested, $35K annual spending, $90K take-home, saves $35K/year. He runs his FI scenario through each tool.

Mad Fientist’s spreadsheet: Plug current balance, savings rate, and target. Output: years to FI = 12.4 at 7 percent real return.

Bogleheads workbook: Same inputs. Output: 12.5 years. Slight variance from rounding and assumed return formulas.

ProjectionLab: Same inputs plus Monte Carlo. Output: median 12.3 years, 90th percentile 9.5 years (good market), 10th percentile 16.8 years (bad market).

Aspire: Aspire’s FI section gives the savings rate (39 percent take-home, 30 percent of gross with employer match) and roughly translates to a 14 to 17 year horizon based on the standard savings-rate-to-years table. Less precise than the dedicated tools.

FinancialAha Financial Planning: Same inputs. Output: 12.4 years at 7 percent real, with a sensitivity table showing 14.8 years at 5 percent and 10.7 years at 9 percent.

The deterministic answers cluster at 12.4 years across all the calculator-style tools. ProjectionLab adds the confidence band (9.5 to 16.8 years range), which is genuinely useful additional information.

When the answer is something other than a spreadsheet

You want Monte Carlo. ProjectionLab. The deterministic median answer from any of the spreadsheets is good for general planning; Monte Carlo is good when you want to know the probability your plan survives.

You want professional advice. A fee-only fiduciary advisor at $250 to $500 an hour for a one-time engagement. They’ll use their own software and produce a multi-page plan. For people with complex situations (business interests, estate considerations, multi-country exposure), this is often worth more than any spreadsheet.

You’re okay with rough math. A simple FIRE calculator on a phone takes 60 seconds. Engaging Data, WalletBurst, FinancialAha’s free FIRE calculator. For an initial sanity check, free calc beats spreadsheet.

The spreadsheets are right when you want to track the same numbers month over month, see the trend, and update your plan as your situation changes. For one-time math, simpler tools win.

Common shortcomings across the field

A few things that no one in this category does well.

Healthcare cost modeling for early retirees. US healthcare between FIRE age and Medicare eligibility (65) is the single biggest variable in early retirement plans. Most tools (including most of the five above) assume employer-comparable coverage continues, which it doesn’t.

Roth conversion ladder modeling. A common FIRE tactic is converting tax-deferred to Roth in low-income early-retirement years. Few spreadsheets handle this elegantly; ProjectionLab does it best, our Annual Tax Planner does it adequately, others ignore it.

Sequence-of-returns risk visualization. A bad first decade in retirement is much worse than a bad last decade. Deterministic projections smooth this away; only Monte Carlo captures it. Pair a spreadsheet with ProjectionLab one-time runs for stress testing if this matters.

Income from non-portfolio sources in retirement. Part-time work, rental income, royalties, business interests. Most tools assume your retirement income is portfolio withdrawals plus Social Security. Reality is messier.

Migration paths

If you’re already using one and curious about another, the moves are mostly painless.

Mad Fientist or Bogleheads to FinancialAha: Open the FinancialAha Financial Planning Spreadsheet. Copy your current balances, contributions, and target spending into the Inputs sheet. Reconcile the years-to-FI output against your old version (should match within rounding).

Aspire to FinancialAha: Aspire’s transactions tab exports as CSV; paste into the FinancialAha transactions sheet. The category mapping needs light remapping. The FI projection is new content; fill in the inputs once.

ProjectionLab to FinancialAha: Export ProjectionLab plan as JSON. Translate the inputs (current balances, contributions, target retirement age) into the FinancialAha Inputs sheet. The deterministic median output should match ProjectionLab’s median Monte Carlo outcome.

FinancialAha to anything: Your data lives in the file. Copy values out as CSV; paste into the new tool.

Recommendation by user type

Someone just starting FI: Free options first. Mad Fientist’s spreadsheet or our free Financial Planning lite is enough to get a number.

Someone tracking FI seriously over years: Pay for a maintained tool. Either FinancialAha Financial Planning ($39 once) or ProjectionLab if Monte Carlo matters ($109/yr or $1,199).

Someone who wants budgeting plus FI in one place: FinancialAha Financial Planning ($39) or build out from Aspire (free) with patience.

Someone with a complex US tax situation: ProjectionLab plus a fee-only advisor consultation. The combination handles edge cases that no single tool does well.

Someone outside the US: FinancialAha (country-agnostic) or build from a Bogleheads workbook with localized tax rules.

Get the template

• Financial Planning Spreadsheet — 40-year life projection with net worth, cash flow, and FIRE in one file.
• Retirement Financial Planning Projections — 40-year accumulation and withdrawal projection with configurable assumptions.
• Personal Finance Bundle — Financial Planning plus Net Worth plus Annual Tax Planner, at a bundled price.
• Personal Finance Bundle — Financial Planning plus Net Worth plus Annual Tax Planner, at a bundled price.

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• ProjectionLab Alternative: Retirement Projections in a Spreadsheet You Can Audit
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