FIRE Calculator

A FIRE calculator estimates how much you need to invest to reach financial independence and how long it may take to get there. In most cases, your FIRE number equals annual spending divided by your safe withdrawal rate, then adjusted using your current portfolio, monthly investing, and expected return.

A FIRE calculator helps you estimate the portfolio size needed to become financially independent and retire early. FIRE stands for Financial Independence, Retire Early. Instead of focusing on a traditional retirement age, the goal is to build a portfolio large enough that a modest annual withdrawal can cover your ongoing living expenses. The core idea is simple: if your investments can sustainably fund your spending, paid work becomes optional rather than mandatory.

Most FIRE planning starts with annual spending, not income. Someone earning $150,000 but spending $60,000 needs a very different portfolio from someone earning the same amount and spending $100,000. A FIRE calculator uses that spending target, a safe withdrawal rate such as 4%, your current invested assets, and your future monthly contributions to estimate a FIRE number and timeline. That makes the concept practical, because you can see whether you are five years away, twenty years away, or already close to financial independence.

In real-world use, a FIRE calculator is helpful when deciding how much to save after a raise, whether a lower spending level would accelerate financial independence, or how sensitive your plan is to different return assumptions. It is also useful for Coast FIRE or Lean FIRE comparisons, because you can test lighter or more conservative spending targets without changing the underlying math. A FIRE calculator does not guarantee a retirement date, but it gives you a disciplined framework for planning around spending, savings rate, and portfolio growth instead of relying on rough guesses.

1. Enter your current age so the calculator can estimate the age at which you may reach financial independence.
2. Add your current invested portfolio, including retirement accounts and taxable investments intended to fund future spending.
3. Type your planned monthly contribution based on how much you expect to invest consistently going forward.
4. Enter your annual spending target, which should reflect the lifestyle you want your portfolio to support.
5. Choose an expected annual return and a safe withdrawal rate, then click Calculate to see your FIRE number, gap, and estimated timeline.

FIRE number = Annual spending / Safe withdrawal rate

• `Annual spending` is the amount you expect to spend each year after retiring.
• `Safe withdrawal rate` is the percentage of your portfolio withdrawn annually, such as 4%.
• `Portfolio gap` equals FIRE number minus your current invested portfolio.
• `Years to FIRE` depends on how quickly contributions and portfolio growth close that gap.

FIRE Number

The FIRE number is the target portfolio needed to support your annual spending using the withdrawal rate you selected.

Portfolio Gap

Portfolio gap shows how much more invested wealth you still need before you can fund the target spending level from your portfolio.

Years to FIRE

This is the estimated time required to reach the target based on your current portfolio, monthly investing, and assumed annual return.

Estimated FIRE Age

Estimated FIRE age converts the timeline into an age-based milestone, which makes the plan easier to compare with career or family goals.

Investment Growth Until FIRE

This metric isolates how much of your progress comes from market growth instead of new contributions, which highlights the value of time in the market.

Assume these inputs for a FIRE plan:

• Current age: 32
• Current invested portfolio: $150,000
• Monthly contribution: $2,500
• Annual spending target: $60,000
• Expected annual return: 7%
• Safe withdrawal rate: 4%

First, the calculator divides $60,000 by 4%, which produces a FIRE number of $1,500,000. Starting from $150,000, the portfolio then grows with monthly contributions of $2,500 and an assumed 7% annual return. Under those assumptions, the portfolio reaches the target in about 16.9 years, or around age 48.9. Contributions over that period total roughly $507,500, while the rest of the progress comes from compounding.

The takeaway is that the target depends heavily on spending, but the timeline depends on both savings rate and market growth. Lowering spending by even $5,000 per year or increasing monthly investing can move the FIRE date forward meaningfully.