Suite home

Agents can set up a plan. Your browser runs it.

This page is the front door for people and for chat tools. It does not calculate. A configured link opens the savings or retirement calculator, and the math stays on your device.

Open a configured plan Open the calculator

Every plan on this page is a share link: the same URL the calculator’s Copy share link button writes.

Sample: 1975–2024, 50 years
Assets: S&P 500 and 10-yr Treasuries
Not in the sample: 1966 and 1973–74
Framing: An illustration, not advice

Privacy

Browser first. No public compute API.

FIREcalc does not accept calculator inputs on a server. There is no unauthenticated API, no remote MCP server, and no model call from this site. agents.txt and agents.json still say that.

A share link puts the inputs in the URL. That URL can sit in browser history, a chat log, or ordinary hosting logs. Treat it like a note that contains the numbers.

A hosted calculator would be a later, explicit opt-in, with the privacy policy updated first. It is not offered here. Details are in the privacy policy.

Connect

ChatGPT, Claude, MCP, and skills

Nothing is published yet. Each card says what exists today and what to use instead. None of these is an install button.

Not published

ChatGPT

Not in the plugin directory.

A later listing, if it exists, should be skills that build share links. It should not be a server that runs the simulation, and it should not sell anything inside the chat.

Use a share link instead

ChatGPT plugin directory is only the directory. It is not a FIREcalc install.

Not published

Claude

No connector or skill to add.

Paste a firecalc.ai share link into the chat, or point Claude at llms.txt. FIREcalc does not run a server for it.

Read llms.txt

Not published

Local MCP

There is no MCP server to add.

A future MCP, if built, would be local to the person’s own computer unless a separate opt-in says otherwise. No install command is provided, because none should be run.

Read agents.json

Not published

Skills

There is no skill pack to download.

A skill for this site should refuse advice, disclose the 1975–2024 sample, and return a firecalc.ai share URL. Read llms.txt before writing that skill.

Read the methodology

None of these sends your numbers to FIREcalc. There is no public, unauthenticated compute API. A hosted calculator would need an explicit opt-in first.

Deep links

Open a configured plan

These are ordinary calculator URLs. Opening one runs that plan in your browser. The seed makes shuffled paths repeat.

Savings

Early saver, 70/30

Shuffled years
1,000 paths
Seed 246813

Age: 35
Saved: $180,000
Income / spending: $95k / $55k
Goal, today’s $: $1,200,000

Assumptions and share URL

Age 35, $180,000 saved, $95,000 income, $55,000 spending, a $1,200,000 goal in today’s dollars, 70% stocks, 2% real income growth, 1,000 paths, seed 246813.

firecalc.ai/?tab=accumulation&currentAge=35&currentSavings=180000&income=95000&expenses=55000&targetAmount=1200000&stockAllocation=70&incomeGrowth=2&savingsSimulationCount=1000&savingsReturnMode=shuffled&seed=246813

Open this savings plan

Retirement

Retire at 55, historical windows

Historical cycles
35-year horizon
Social Security off

Portfolio: $1,200,000
Spending: $48,000/yr
Stocks: 60%
Tax: Flat 15%

Assumptions and share URL

Retire at 55 with $1,200,000, spend $48,000 a year with inflation, 60% stocks, 35-year horizon, flat 15% tax, Social Security off. Historical cycles ignore the path count. The sample is 1975–2024, so this is not a 1966 test. Seed 246813 is stored on the link and does not change historical windows.

firecalc.ai/?tab=retirement&retirementAge=55&retirementSavings=1200000&annualWithdrawal=48000&retirementStockAllocation=60&withdrawalAdjustment=true&taxRate=15&taxMode=simple&retirementLifeExpectancy=35&simulationCount=1000&retirementReturnMode=historical&includeSS=false&ssMonthlyBenefit=2000&ssClaimingAge=67&includeSpouseSS=false&spouseSSMonthlyBenefit=1500&spouseSSClaimingAge=67&includeOtherIncome=false&monthlyPension=0&pensionStartAge=65&monthlyOtherIncome=0&otherIncomeDuration=0&seed=246813

Open this retirement plan

Retirement

Social Security on, bracket taxes

Shuffled years
2,000 paths
33-year horizon

Portfolio: $900,000
Spending: $54,000/yr
Social Security: $2,400/mo at 67
Tax: MFJ + 4.5% state

Assumptions and share URL

Retire at 62 with $900,000, spend $54,000 a year with inflation, 50% stocks, 33-year horizon. Social Security is on: $2,400 a month at 67, claimed at 67, so the portfolio pays everything until then. Taxes use 2025 married-filing-jointly brackets, a 60/20/20 pre-tax / Roth / taxable mix, and a 4.5% state rate. Social Security income is inside this success rate, so it is not a portfolio-only result. Seed 246813.

firecalc.ai/?tab=retirement&retirementAge=62&retirementSavings=900000&annualWithdrawal=54000&retirementStockAllocation=50&withdrawalAdjustment=true&taxRate=15&taxMode=detailed&taxFilingStatus=mfj&taxPreTaxPct=60&taxRothPct=20&taxTaxablePct=20&taxOptimizeOrder=true&taxStateRate=4.5&retirementLifeExpectancy=33&simulationCount=2000&retirementReturnMode=shuffled&includeSS=true&ssMonthlyBenefit=2400&ssClaimingAge=67&includeSpouseSS=false&spouseSSMonthlyBenefit=1500&spouseSSClaimingAge=67&includeOtherIncome=false&monthlyPension=0&pensionStartAge=65&monthlyOtherIncome=0&otherIncomeDuration=0&seed=246813

Open this plan

The same keys are what the in-app Share button writes. firecalc-io.js builds and reads them without the page.

Stress packs

Named historical stress packs

Six real stretches of the 1975–2024 table. A pack runs a retirement plan through those exact years, in order, in the browser, and says which years it used. Each link below is a challenge link: it names the pack and nothing else.

A pack runs for the plan’s length, never past 2024. There is no pack for 1966 or 1973–74, which are before the table. There is also none for Black Monday or the COVID crash, because 1987 and 2020 were up years in annual data. Agents can add pack=<id> to a retirement share link to open that pack with the plan’s numbers.

For a chat assistant

Ask for the real knobs, then hand back a link

Ask firstAsk which calculator, the return path (shuffled years or historical cycles), the stock mix, taxes, and whether Social Security is on. Do not invent a 7% return.
Build the linkBuild a https://firecalc.ai/ URL with the share keys. Do not send the numbers to a FIREcalc server. There isn’t one.
Disclose the sampleSay the sample is US large-cap stocks and 10-year Treasuries from 1975 through 2024. It does not include 1966 or 1973–74. This is an illustration, not advice.
Hand offSend the person here for charts, the path table, and editing. Chat is a poor place to scrub a plan.

Deep config

The knobs are specific. A toy summary is not.

A useful assistant uses the controls the site already has. Hiding them, or substituting a generic Monte Carlo, will not match FIREcalc.

Returns

Shuffled years draw each year independently from 1975–2024. Historical cycles walk the years that actually followed. There is no custom mean, volatility, or fee. “Monte Carlo” here means that shuffle, not a normal distribution.

Mix

One allocation: S&P 500 total return versus that year’s 10-year Treasury total return. Treasuries can be negative. There is no international sleeve, cash bucket, or glide path.

Taxes

Flat rate, or 2025 federal brackets with an account mix and a state rate. The “optimize withdrawal order” switch does not change results, because separate account balances are not tracked.

Social Security and other income

Off by default. Benefit at age 67, claiming age 62–70, optional spouse, a nominal pension, and other income with a duration. Turning them on raises the success rate. Say so.

Inflation and horizon

Inflation is the CPI on each historical row. Retirement can raise spending with that CPI. You cannot type a flat 3% inflation rate. Retirement length is 5–50 years. The savings search stops at 50 years.

Seed

Shuffled paths keep a seed until you reshuffle. The share URL carries it, so two people opening the same link see the same paths. Historical cycles do not use the seed.

What the engine leaves out

Fees, a glide path, and a separate cash bucket.
Returns before 1975, and markets outside US large-cap stocks and 10-year Treasuries.
Early-withdrawal penalties, RMDs, NIIT, IRMAA, and ACA premiums.
Inflation adjustment on a pension. It stays flat in nominal dollars.

Suite map

What exists, and what does not

One engine, several questions. Only the rows marked Live are on the site.

Years to a savings goalLiveOn the calculator. Goal is today’s purchasing power. Contributions are income minus spending, and never below zero.
Retirement survivalLiveOn the calculator. Success means the portfolio is above zero at the end of every year of the horizon.
Share linkLiveOn the calculator. firecalc-io.js encodes and decodes the same query keys.
Spending or stock-mix stressChart onlyA chart after you run retirement or savings. Not a separate tool.
Social Security claimingInput onlyAn input (62–70), off unless you turn it on. No side-by-side 62 vs 70 tool.
Coast, barista, sabbaticalNot builtCoast is not “set spending equal to income”; the savings model does not solve for a coast number.
Named historical stress packsLiveOn the retirement results. Six named stretches inside 1975–2024, each with its exact years and a share card drawn in the browser. See the pack list.
Chat plugin, skills, MCPNot publishedSee the cards above. They are not install buttons.

Methodology

Files for people and agents

Success, returns, inflation, taxes, and Social Security are defined in the long methodology note. llms.txt, agents.txt, and agents.json name this page as the suite home. They still say there is no MCP server and no public compute API.