FIRE & Independence

FIRE Spending Rate Stress Tester

Test portfolio survival at different spending rates with projected balances at 10, 20, and 30 years.

Stress Test Results

Current withdrawal rate

4.00%

Max sustainable rate

6.20%

At your current spending, portfolio survives the full analysis period.

Spending Rate Comparison

Rate	Spending	Year 10	Year 20	Year 30	Survives
3.0%	$30,000.00	$1,509,106.82	$2,382,305.78	$3,935,796.73	Yes
3.5%	$35,000.00	$1,432,766.06	$2,134,409.33	$3,323,053.68	Yes
4.0%	$40,000.00	$1,356,425.30	$1,886,512.89	$2,710,310.63	Yes
4.5%	$45,000.00	$1,280,084.54	$1,638,616.44	$2,097,567.58	Yes
5.0%	$50,000.00	$1,203,743.79	$1,390,719.99	$1,484,824.53	Yes

How to use it

Enter portfolio value, current annual spending, expected return, inflation, and time horizon. Use your actual spending number rather than a general estimate.
Read the spending rate comparison table to see projected balances at 10, 20, and 30 years for withdrawal rates from 3% to 5%. Focus on which rates keep the portfolio positive through your full horizon.
The max sustainable rate shows the highest withdrawal percentage that survives the entire time horizon. If your current rate exceeds this, you are on a depletion path.
Compare 3.5% and 4.5% withdrawal rates side by side. The difference in 30-year outcomes is often dramatic and shows how sensitive your plan is to small spending changes.
Re-run after major market moves, spending changes, or when your time horizon shifts. Track your current withdrawal rate against the max sustainable rate over time.

AI Integrations

Contract, discovery endpoints, and developer notes for agent use.

Always available for agents

Tool contract JSON

https://aifinhub.io/contracts/fire-spending-stress-tester.json

Stable input and output contract for this exact tool.

Human review

People can use the browser page to sense-check outputs and charts, but agents should still execute against the contract and discovery endpoints.

/agent-tools.json - machine-readable tool index.
/llms.txt - human-readable model discovery guide.
/.well-known/webmcp.json - WebMCP capabilities manifest.
/.well-known/ai-plugin.json - plugin-style discovery manifest.

{
  "tool": "fire_spending_stress",
  "portfolio_value": 1000000,
  "annual_spending": 40000,
  "expected_return_percent": 7,
  "inflation_percent": 2.5,
  "time_horizon_years": 30
}

Open tool contract JSON Open AI integrations guide

Expand developer notes

Agent playbook

Resolve FIRE Spending Rate Stress Tester from /agent-tools.json and open its contract before execution.
Validate inputs against the contract schema instead of scraping labels from the page UI.
Open the browser page only when a person wants to review charts, assumptions, or related tools.

Agent FAQ

Should ChatGPT, Claude, or another agent click through the UI?

No. Start with /agent-tools.json, then follow the tool's contract URL. The page UI is for human review, not parameter discovery.

When do tools show Quick and Advanced?

Every tool opens in Quick Start first. Advanced Controls keeps the same scenario, reveals more assumptions or diagnostics, and every tool keeps AI integrations inline below the instructions.

When should an agent still open the browser page?

Open it when a human wants to sense-check the output, review the chart, or keep exploring related tools after the calculation finishes.

Questions people usually ask

What does this stress tester show?

It projects your portfolio balance at 10, 20, and 30 years under five withdrawal rates (3%, 3.5%, 4%, 4.5%, 5%). You can see which rates deplete the portfolio and which keep it growing, helping you choose a sustainable spending level.

Why is this not a Monte Carlo simulation?

This uses deterministic projections with a single expected return and inflation rate. This makes results reproducible and instant in the browser. For volatility-aware modeling, use the FIRE calculator which includes Monte Carlo simulation.

What is a safe withdrawal rate?

The 4% rule (from the Trinity Study) suggests withdrawing 4% of your initial portfolio annually, adjusted for inflation, gives a high probability of lasting 30 years. However, this depends heavily on sequence of returns, actual inflation, and portfolio allocation.

How do I read the max sustainable rate?

It is the highest withdrawal percentage where your portfolio survives the full time horizon. If your current spending exceeds this rate, you are drawing down the portfolio and it will eventually deplete.

What if my portfolio does not survive at 4%?

Either reduce spending, extend part-time income, adjust your portfolio allocation for higher returns, or plan for a shorter retirement horizon. Small spending reductions have outsized effects on portfolio longevity.

Is my data stored?

No. All calculations happen in your browser. Nothing is stored or transmitted.