Can You Coast FIRE with a Pension? Here's the Calculator to Find Out

What if your pension could carry you all the way to early retirement — without needing to save another dime?

That’s the central question behind Coast FIRE, a financial independence strategy that’s more flexible (and realistic) than traditional FIRE. And if you’ve got a pension? You may already be closer than you think.

In this post, we’ll walk you through how pensions factor into your Coast FIRE number, the math behind it, and how to use our free Coast FIRE Calculator to find out exactly when you can stop saving and start coasting.

The Problem: You Might Be Over-Saving (or Underestimating Your Pension)

Most people are stuck in a cycle of aggressive saving, afraid they’ll never have enough to retire. But if you have a defined benefit pension, there’s a hidden asset already doing the heavy lifting for your future.

The problem is, few people know how to incorporate their pension into a FIRE plan. Traditional spreadsheets often ignore pensions, or overcomplicate the math. That’s why we built a calculator specifically for this scenario.

But first, let’s get clear on what Coast FIRE actually means — and how your pension fits in.

What is Coast FIRE?

Coast FIRE (short for Coasting Financial Independence, Retire Early) means reaching a point where your existing savings — when left alone to grow — will eventually fund your retirement, even if you stop saving today.

Here’s the logic:

• You invest aggressively early,
• Reach your “Coast number” (the amount you need invested now to grow into your full retirement fund),
• Then stop saving and let compound interest do the work,
• You continue working to cover expenses — but not to save.

The result? Freedom from financial anxiety, optionality, and a powerful psychological shift: you’ve already won.

How to Calculate Coast FIRE with a Pension

To calculate your Coast FIRE number with a pension, you need to account for the guaranteed income your pension will provide in retirement — and subtract its present value from your required future assets.

Let’s break it down.

Step 1: Define Your Retirement Needs

• Annual retirement spending: $S = 40,000
• Retirement age: 60
• Safe withdrawal rate (SWR): 4%

That means you’ll need:

Step 2: Calculate Present Value of Pension

If your pension will pay $P = 15,000 annually starting at age 60, the equivalent value it replaces is:

So your adjusted FIRE target becomes:

Step 3: Coast FIRE Math

You now need $625,000 at age 60. So the question becomes: How much do you need today for it to grow to $625,000 by 60?

Using a growth rate r = 7% and years until retirement t = 30, the formula is:

So if you have ~$76K invested today, and a pension of $15K/year later — you’re done saving. You’ve Coast FIRED.

Why Coast FIRE Works (and Why Pensions Supercharge It)

Most retirement plans are built around anxiety: “Save more, spend less, retire later.” But Coast FIRE flips the script.

With a pension:

• You reduce your target nest egg, since some of your income is guaranteed.
• You hit Coast FIRE sooner, since the required present value is lower.
• You gain clarity, seeing the real impact of your pension on your plan.

Instead of trying to reach $1M in savings, maybe $600K is enough — if you know how to factor in your pension correctly.

Common Mistakes When Trying to Coast FIRE with a Pension

Even smart planners miss these traps:

• Ignoring inflation: Make sure your pension is inflation-adjusted, or account for its erosion over time.
• Overestimating returns: Stick to conservative growth assumptions (6–7% is reasonable).
• Undervaluing your pension: A $15K/year pension is worth hundreds of thousands.
• Not calculating the “Coast number” precisely: Ballpark estimates lead to over-saving or false confidence.

Tools to Help You Coast FIRE (Without a Spreadsheet)

Running the numbers manually is time-consuming. That’s why we created the Coast FIRE Calculator — a free, browser-based tool that:

• Integrates pension income
• Shows if you’ve already hit your Coast number
• Visualizes how your assets grow over time
• Requires zero sign-up or downloads

It’s built for real people. No finance degree required.

Your Next Steps: Coast FIRE in 5 Moves

1. Estimate your annual spending in retirement
2. Calculate your FIRE number using the 4% rule
3. Determine how much your pension offsets this target
4. Use our calculator to find your Coast number
5. Decide: do you want to keep saving — or coast?

Final Thought: If You’ve Got a Pension, You Might Already Be Coast FIRE

Many mid-career professionals are closer than they think — especially if they have a pension. But clarity requires calculation.

Use the Coast FIRE Calculator today and see if you can stop saving sooner than expected. Freedom might be one click away.