How to Use MyFIRE: Your Complete Getting Started Guide

Retirement calculators have a reputation for being cold, confusing, and full of fields that make you feel like you're doing your taxes. MyFIRE is different — but it does ask for real numbers, and knowing which numbers to enter (and why) makes all the difference.

This guide walks you through every step with a running example. Meet Jamie: 38 years old, earns $90k a year, has been saving steadily for a decade, and wants to know if retiring at 55 is actually possible. By the end of this guide, Jamie — and you — will have a complete picture.

New to the FIRE movement? Start with What is FIRE? first, then come back here.

The very first inputs are your Current Age, Semi-Retire Age, and Full Retire Age. These three numbers define the shape of your entire plan.

• Current Age — how old you are right now. Easy.
• Semi-Retire Age — the age when you'd like to step back from full-time work. Maybe you go part-time, freelance, or switch to something lower-stress. You still earn some income here, but less.
• Full Retire Age — when you stop working entirely and live off your portfolio and Social Security.

You can set Semi-Retire and Full Retire to the same age if you plan to go straight from full-time to done. Many people find a two-phase approach gives them more breathing room — especially before Social Security kicks in.

This section asks for what you've already saved. It covers four buckets:

• 401(k) / 403(b) — your workplace retirement account balance today
• Roth IRA — your after-tax retirement account. Enter the current balance.
• Taxable brokerage — any investment accounts outside of retirement accounts (Vanguard, Fidelity, Schwab accounts not labeled "IRA")
• Cash savings — money market, HYSA, or cash set aside for retirement (not your emergency fund)

Don't include your emergency fund, home equity, or possessions. Only include assets you'd actually draw on in retirement.

Now tell the planner how much you're adding each year. There are three inputs here:

• Annual 401(k) contribution — what you put in, plus any employer match. The 2026 limit is $24,500; with a 50% match on 6% of salary, that can push total contributions well above $30k.
• Annual Roth IRA contribution — the 2026 limit is $7,500 ($8,600 if you're 50+). Enter $0 if you're over the income limit for direct contributions.
• Expected Social Security benefit — check your estimate at ssa.gov. Enter your monthly benefit at your planned retirement age. If you're unsure, $1,500–$2,000/month is a reasonable placeholder for someone earning $90k.

This is the assumed annual growth rate for your investments during the accumulation phase. It matters more than almost any other input — a 1% difference over 20 years can mean hundreds of thousands of dollars.

Here's what's realistic:

• 7% — the historical real return of the US stock market after inflation. This is the standard FIRE planning assumption.
• 6% — more conservative. Appropriate if you hold bonds or are nervous about future returns.
• 8–9% — optimistic. The nominal (pre-inflation) historical return. Fine for stress-testing, but don't plan on it.

MyFIRE also asks for a withdrawal-phase return — what your portfolio earns once you're actually retired and drawing it down. This is typically 0.5–1% lower than your growth rate, because most people shift to a more conservative allocation as they approach and enter retirement.

This is the most important number in your plan. Monthly spending in retirement determines your entire target — because your portfolio needs to be 25× your annual spending to be considered financially independent.

Think carefully here. Include:

• Housing (mortgage, rent, or property taxes if paid off)
• Food, utilities, transport
• Healthcare — this is often the biggest surprise. Budget $600–$1,000/month before Medicare at 65.
• Travel, hobbies, and "fun money" — early retirement often costs more than people expect because you're actually living your life

Once you've filled in the inputs, the planner shows a set of KPIs — key numbers that tell the story of your retirement. Here's what each one means:

• Corpus at Full Retire — your projected portfolio size on the day you stop working. If this is above your FI target, you're good. If it's below, the plan needs adjustment.
• Bridge Fund — the amount you need in taxable accounts to fund the gap between when you retire and when your retirement accounts (59½) and Social Security become available. Learn more about bridge funds.
• Wealth at 90 — how much is left in your portfolio if you live to 90. A positive number means your plan is sustainable. A large positive number means you're being too conservative with spending.
• Monthly Surplus/Gap — whether your retirement income (portfolio withdrawals + Social Security + any part-time income) covers your planned spending each month.

Your Two Command Centres

MyFIRE organises your results into two tabs: Plan and Analysis.

The Plan Tab is your home base. It shows:

• Monthly Savings Targets — how much to save each month in your bridge fund and retirement accounts
• Year-by-Year Projection — your portfolio at every age from now to 100
• Your Freedom Dashboard — a summary of your 6 most important numbers (see below)

The Analysis Tab goes deeper:

• 4% Rule Check — does your corpus support your planned spending?
• Monte Carlo Simulation — 1,000 randomised market scenarios to test your plan's resilience
• Scenario Comparison — compare your current plan against two saved alternatives side by side
• AI Insights — personalised analysis of your specific numbers

A good approach: start with the Plan tab to understand your numbers. Switch to Analysis once you want to stress-test them or explore what-if scenarios.

Six Numbers That Tell Your Whole Story

Scroll to the bottom of the Plan tab and you will find your Freedom Dashboard — a summary card that answers the questions that matter most.

• Life on your terms from age X — the age when your portfolio can fully support your lifestyle without any earned income. This is your FI age.
• Chance you never run out — X% — from the Monte Carlo simulation: the percentage of 1,000 market scenarios where your money lasts to age 90. Above 85% is solid. Above 90% is excellent.
• X years ahead of average — the average American retires at 64. This shows how many years earlier your plan has you financially free.
• Could you go part-time today? — compares your current bridge fund savings to what you would need to semi-retire right now. If it says Not yet, it tells you exactly how much more you need.
• Your FI number — $X.XM — the total portfolio you need to be financially independent, based on the 4% rule and your planned retirement spending.
• You are X% there — your current savings divided by your FI number. Watching this number grow each year is genuinely motivating.

What If You Tried a Different Path?

The Analysis tab includes a 3-way scenario comparison. Your current plan is always Scenario A. You can save two alternatives as Scenario B and C, then compare them side by side on one screen.

This is most useful for questions like:

• What if I retire 3 years earlier — how does that change my wealth at 90?
• What if my partner stops working at 50 instead of 55?
• What if we move somewhere cheaper and cut spending by $1,000 a month?

To save a scenario: adjust your inputs, click the snapshot icon in the comparison panel, and give it a name. Switch your inputs back to your main plan. You can now see both versions compared side by side.

This is one of MyFIRE's most powerful features — and one that few other retirement planning tools offer for free.

The Monte Carlo button runs 1,000 simulated retirement scenarios using randomised market sequences. Instead of assuming a steady 7% return every year, it models what actually happens — good years, bad years, crashes, and booms in random order.

The result is a success rate — the percentage of scenarios where your money lasts until age 90 (or whatever end age you've set).

• 90%+ — very robust. You could probably spend a little more.
• 80–90% — solid. This is where most FIRE planners aim.
• 70–80% — workable but worth revisiting spending or contributions.
• Below 70% — the plan needs adjustment. Small changes to spending or retirement age make a big difference here.

The AI Insights panel is where MyFIRE goes from calculator to advisor. It reads your actual numbers and gives you personalised analysis — not generic tips.

You get 3 free questions per week. Make them count. Here are the questions that generate the most useful answers:

• "What's the single biggest risk to my plan?" — forces the AI to prioritise instead of listing everything
• "If I delay full retirement by 2 years, how much does that change my wealth at 90?" — quantifies a specific trade-off
• "Am I saving in the right account types given my income?" — gets you tax strategy advice specific to your situation
• "What would I need to change to hit 90% Monte Carlo success?" — directly actionable

You can also type questions directly into the chat box below the analysis. The AI knows your plan numbers — so ask specific questions, not generic ones.

Why There Is a Small Cost for AI Questions

MyFIRE AI knows your entire plan — your ages, savings, spending targets, Monte Carlo results and bridge fund gap. It gives you analysis that is specific to your numbers, not generic advice.

We offer 3 free questions every week. Beyond that, there is a small fee:

• $1.97 for 10 questions
• $4.94 for 50 questions
• $9.98 for 200 questions

The honest reason: every AI question has a real computing cost that we pay for. We have kept the price as low as we possibly can so that personalised retirement analysis is accessible to everyone.

Your questions never expire. Buy 50 today and use them over 6 months.

Once your numbers feel right, save the plan. You can create a free account with just an email address — no credit card, no catch.

Saving unlocks cloud sync: your plan is stored securely and available on any device. You can also save multiple named scenarios — "Base Case," "Retire at 50," "What if I go part-time at 45?" — and compare them side by side.

Every time you get a raise, change jobs, or adjust your spending, take five minutes to update your plan. The best retirement plan is one you actually maintain.

Common mistakes to avoid

• Not including Social Security. For most people, $1,500–$2,500/month in guaranteed income dramatically changes the required portfolio size. Include it, even conservatively.
• Using pre-inflation returns. If you use 10% as your return, your spending assumptions need to keep pace with inflation too. Use real (inflation-adjusted) returns of ~7%, or adjust both sides consistently.
• Ignoring healthcare before 65. It's the most commonly underestimated cost in early retirement. Budget $800–$1,200/month per couple on the ACA marketplace.
• Planning for 85. Life expectancy is increasing. Model to 90 or 95. The downside of outliving your money is much worse than the "downside" of having money left over.
• Only running one scenario. Your first scenario is a guess. Run three: optimistic, realistic, and pessimistic. The gap between them tells you how much your plan depends on assumptions holding true.