What happens if inflation averages 4 percent?

Specific retirement question

This scenario compares a higher inflation setting with other assumptions kept close. The key question is how quickly purchasing power erosion can shorten success odds in early and mid-retirement years.

It is an educational simulation. The output does not guarantee a result and does not replace personalized planning.

Inputs used

• Current age: 40
• Target retirement age: 57
• Current savings: $500,000
• Monthly contribution: $2,000
• Expected return: 7.0%
• Inflation: 4.0%
• Annual spending: $65,000 in today’s dollars
• Withdrawal rate: 3.5%
• Volatility: 17%

Result summary

Estimated FIRE number: about $1,860,000 when inflation is set to 4%.

Projected portfolio: around $700,000 at age 57 in deterministic modeling.

Safe withdrawal amount: roughly $24,500 from the projected portfolio.

Success rate: around 61% in this inflation-stress setup.

Tradeoff analysis

• Higher inflation target: pushes spending to rise faster than nominal growth alone.
• Portfolio durability: a portfolio that appears sufficient in nominal terms may be insufficient in real terms.
• Spending categories: discretionary categories often absorb shocks unevenly, so category-level planning helps.
• Timing flexibility: the value of optional spending cuts increases when inflation is high.

Monte Carlo interpretation

A 61% success rate means only 610 simulated paths survived this inflation stress profile. This signals that sequence plus inflation can dominate a simple average-return lens.

Use this result to compare against your preferred spending flexibility, especially in the first 10 years of retirement.

Sensitivity notes

• At 3% inflation, FIRE target can be materially lower for the same lifestyle assumptions.
• At 4.5% inflation, many runs fail earlier unless spending can flex.
• Higher return assumptions can improve success, but not always enough to offset sustained inflation drag.
• Changing retirement age by two years can often do more than a small inflation change in expected outcomes.

Common mistakes

• Assuming historical average inflation will persist without testing a higher setting.
• Treating category spending as fixed and not adaptable under inflation pressure.
• Using the deterministic FIRE number without reviewing simulation spread.

Scenario links

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