MRI Calculator (Monthly Retirement Income)
Use this calculator to estimate how much monthly retirement income your savings strategy may support.
What is an MRI calculator?
On this page, MRI stands for Monthly Retirement Income. The calculator estimates how large your retirement nest egg could become and converts that balance into a monthly income estimate based on your retirement timeline and return assumptions.
This is useful when your goal is practical and concrete: “How much can I spend each month when I stop working?” rather than “How big does my portfolio need to be?”
What this calculator estimates
- Projected nest egg at retirement from current savings + monthly contributions.
- Sustainable monthly income at retirement over your expected retirement years.
- Inflation-adjusted income in today’s dollars so the result is easier to understand.
- Required nest egg to support your desired monthly income goal.
- Estimated contribution gap so you know if your plan is on track.
How the MRI calculation works
1) Project growth before retirement
Your current savings are compounded monthly at your expected pre-retirement return. Then monthly contributions are added and also compounded.
2) Translate your income goal for inflation
If you want $5,000/month in today’s dollars, you will likely need a larger nominal amount by the time you retire. The calculator inflates your target forward using your inflation assumption.
3) Estimate retirement income
At retirement, the calculator treats your nest egg as a pool that must provide monthly withdrawals over your retirement duration. It uses your expected return during retirement and your life expectancy to estimate a sustainable monthly payout.
Example interpretation
Suppose your result shows:
- Projected nest egg: $1.45M
- Estimated monthly retirement income: $6,100 (future dollars)
- Inflation-adjusted income: $3,900 (today’s dollars)
That means your portfolio might support $6,100/month at retirement date prices, which may feel like about $3,900/month in current purchasing power. If your goal is $5,000/month in today’s dollars, you likely need to increase contributions, delay retirement, or raise return assumptions (carefully).
How to improve your projected MRI
Increase monthly contributions
Even modest contribution increases can compound significantly over long timelines.
Start earlier
Time is a dominant factor. Early contributions have more years to grow.
Review portfolio allocation
A portfolio aligned with your risk tolerance and time horizon can improve long-term outcomes, but higher return assumptions should always be realistic.
Delay retirement by a few years
This helps in three ways at once: more contribution time, fewer withdrawal years, and potentially larger Social Security or pension benefits.
Common mistakes when using retirement calculators
- Confusing nominal and real dollars: Always check whether values include inflation.
- Using aggressive return assumptions: Optimistic numbers can hide future shortfalls.
- Ignoring retirement duration risk: A longer retirement requires a more durable withdrawal plan.
- Forgetting taxes and healthcare: Real-world retirement spending is usually higher than expected.
Important note
This MRI calculator is a planning tool, not financial advice. Markets are uncertain, and actual outcomes will vary. Use the output as a starting point, then stress-test with conservative assumptions and consult a licensed advisor for a personalized plan.
Bottom line
If your goal is financial clarity, MRI is one of the best metrics to track. A clear monthly income target can guide your savings rate, retirement date, and investment strategy more effectively than vague “someday” goals.