Retirement Calculator | TheSmartCalculator

Current Age

Retirement Age

Current Savings ($)

Monthly Contribution ($)

Expected Annual Return (%)

About the Retirement Calculator

Retirement planning sounds overwhelming — but it all comes down to a few key numbers: how much you have saved, how much you save monthly, how long until you retire, and what return you expect. Our Retirement Calculator connects these dots and tells you definitively whether you're on track, and if not, exactly how much you need to save to reach your goal.

It's never too early or too late to run this calculation. The earlier you know your number, the more time you have to course-correct.

How It Works

Enter your current age, desired retirement age, current savings, monthly contribution, expected annual return, and desired monthly retirement income. The calculator projects your balance at retirement using compound growth, estimates how long your savings will last, and shows you the savings gap (if any) along with what monthly contribution would close it.

Formula / Key Reference

Balance at Retirement = Current Savings × (1+r)^years + Monthly Contribution × [(1+r)^n − 1] / r

Monthly Withdrawal Sustainable:

PMT = Balance × r / [1 − (1+r)^(-n)]

Where: r = monthly return rate, n = months in retirement

Real-World Example

Current age: 40

Target retirement age: 67

Years to retirement: 27

Current savings: $85,000

Monthly contribution: $800

Expected annual return: 7%

Desired monthly income in retirement: $4,500/month for 25 years

Balance at retirement:

$85,000 × (1.07)^27 + $800 × 12 × [(1.07)^27 − 1] / 0.07

≈ $558,200 + $723,400 = $1,281,600

This balance funds approximately $9,014/month for 25 years — well above the $4,500 target.

Note: At $4,500/month for 25 years at 5% withdrawal growth, you need approximately $762,000 at retirement. This person is on track with a $519,000 buffer. Social Security income (not included here) would provide additional support.

Common Uses

Determining if your current savings rate will meet your retirement income goal

Calculating how much you need to save monthly to retire at a target age

Evaluating the impact of starting retirement planning later in your career

Modeling different retirement ages to understand the trade-offs

Showing the cost of pausing contributions during financial hardship

Frequently Asked Questions

How much do I need to retire? ▼

A common rule of thumb is the '25× rule': multiply your desired annual retirement income by 25. This is based on the 4% safe withdrawal rate — research suggesting you can withdraw 4% of a diversified portfolio annually with a high probability of never running out of money over 30 years. If you need $60,000/year, you need $1,500,000 saved.

What is the 4% withdrawal rule? ▼

The 4% rule originates from the Trinity Study (1998), which analyzed historical stock and bond return data. It found that a 50/50 portfolio could sustain 4% annual withdrawals for 30 years with a 95%+ success rate. It is a planning heuristic, not a guarantee — sequence-of-returns risk and unusually long retirements may require a lower withdrawal rate (3–3.5%).

Should I count Social Security in my retirement calculation? ▼

You can include it, but conservatively. The average Social Security benefit in 2024 is approximately $1,900/month. You can get your personal estimate at ssa.gov. Factor in that Social Security may face funding challenges beyond 2034 under current projections, so some planners use 75–80% of the estimated benefit as a conservative assumption.

What is the best retirement account to use? ▼

The main options are: 401(k)/403(b) — pre-tax contributions, tax-deferred growth, taxed at withdrawal; Roth IRA/Roth 401(k) — after-tax contributions, tax-free growth and withdrawal; Traditional IRA — pre-tax if deductible, otherwise post-tax. Most advisors recommend contributing to a 401(k) up to the employer match, then maxing a Roth IRA, then returning to the 401(k) if income allows.