{"uid":"cap_JbmLyXoXBYdVw6RVnVKvT","slug":"investing-math-fire-number-calculator-b131f7b1","name":"Investing Math – FIRE Number Calculator","description":"Financial-independence number from yearly spending and a withdrawal rate, and years to reach it from savings and contributions.","url":"https://invest-math.x402tookit.com/fire-number?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["annualSpending"],"properties":{"realReturnPct":{"type":"number","description":"Yearly return after inflation in percent, default 5"},"annualSpending":{"type":"number","description":"Yearly spending you want to cover"},"currentSavings":{"type":"number","description":"Invested savings today, default 0"},"withdrawalRatePct":{"type":"number","description":"Safe withdrawal rate in percent, 2 to 10 (default 4)"},"yearlyContribution":{"type":"number","description":"What you add each year, default 0"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"asOf":{"type":["null","string"]},"source":{"type":["null","string"]},"reasons":{"type":["array","null"],"items":{"type":"string"}},"summary":{"type":["null","string"]},"verdict":{"type":["null","string"]},"degraded":{"type":["boolean","null"]},"reachable":{"type":["boolean","null"]},"disclaimer":{"type":["null","string"]},"fireNumber":{"type":["null","number"]},"notChecked":{"type":["array","null"],"items":{"type":"string"}},"progressPct":{"type":["null","number"]},"yearsToTarget":{"type":["null","number"]},"currentSavings":{"type":["null","number"]},"impliedMultiple":{"type":["null","number"]},"withdrawalRatePct":{"type":["null","number"]},"monthlySpendingCovered":{"type":["null","number"]}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_JwRSAo37DP8zQm_zN_7Cv","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates the financial-independence target (FIRE number) from annual spending and withdrawal rate, plus the estimated years to reach it given current savings and yearly contributions.","exampleAgentPrompt":"I spend $55,000 a year and have $120,000 invested so far — using a 4% withdrawal rate and adding $18,000 per year, how many years until I hit my FIRE number and what is that target amount?","exampleUseCases":[{"title":"Early retirement timeline for aggressive saver","prompt":"I'm 32, spend $48,000 a year, have $85,000 saved, and contribute $24,000 per year. Using a 4% withdrawal rate and a 6% real return, how many years until I reach financial independence and what's my FIRE number?"},{"title":"Comparing withdrawal rate impact on FIRE target","prompt":"My annual spending is $70,000. Can you calculate my FIRE number under both a 3.5% and a 4% safe withdrawal rate so I can see the difference in how much I need to save?"},{"title":"Checking FIRE progress with no extra contributions","prompt":"I've got $500,000 invested already and spend $40,000 per year. With a 4% withdrawal rate and 5% real return, and no additional contributions, what percentage of my FIRE goal have I hit and how much longer until I'm done?"}],"resultDescription":"Returns the FIRE number (total portfolio needed), years to reach the target, current progress as a percentage, the implied savings multiple relative to annual spending, and how much monthly spending is already covered by current savings. Also includes metadata like withdrawal rate used and current savings echoed back.","failureModes":["Missing required annualSpending parameter returns an error","withdrawalRatePct outside 2–10 range may be rejected or clamped","Negative or zero annualSpending produces nonsensical results","Very high yearlyContribution relative to FIRE gap may return 0 or near-0 years","If currentSavings already exceeds the FIRE number, yearsToTarget may return 0"],"whenToPreferThis":"Use this endpoint when a user needs to compute their FIRE number from annual spending and a safe withdrawal rate, or wants to estimate years to financial independence given existing savings and contributions. It is the right choice for personal-finance agents handling retirement planning, FI/RE goal tracking, or 'how long until I can quit my job' queries. Prefer it over generic compound-interest or savings calculators when the specific FIRE/withdrawal-rate framing is needed.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T13:12:38.306Z","isFirstParty":false,"canonicalSlug":"investing-math-fire-number-calculator-b131f7b1"}