---
title: "How Long Will Money Last Calculator"
canonical: "https://www.simplyinsurance.com/how-long-will-money-last-calculator/"
description: "How long will money last calculator - how it estimates your retirement runway, the inputs it needs, and what the 4% rule says about withdrawals."
silo: "annuities"
published: "2026-07-24"
author: "sa-el"
source: "Simply Insurance"
---
**How long will your money last in retirement?** A retirement money-last calculator estimates your runway by dividing your savings by your annual spending — but inflation, taxes, investment returns, and withdrawal strategy all shift that number significantly. Most planners target 25–30 years of income; the 4% rule suggests withdrawing no more than 4% of your balance per year to make savings last 30 years. Adding guaranteed income sources like Social Security or [an annuity](https://www.simplyinsurance.com/compare-annuity-quotes-online/) can stretch — or even eliminate — the risk of outliving your money.

---

## How Long Will Money Last Calculator: What It Is and How It Works

A "how long will money last" calculator is a simple but powerful tool. You plug in your current savings, your expected monthly spending, and an assumed rate of return, and it tells you how many months or years your nest egg will survive. That's it at the core — but the details matter enormously.

### What inputs does a retirement money calculator need?

Most calculators ask for the same handful of numbers:

- **Current savings balance** — the total you're starting with
- **Monthly (or annual) withdrawal amount** — what you plan to spend
- **Expected annual return** — what your portfolio earns while you draw it down
- **Inflation rate** — how fast your cost of living rises each year
- **Additional income** — Social Security, pension, part-time work

Some tools also ask your age, so they can flag whether you're on track for a 20-year or 35-year retirement horizon.

### How to read your results — months vs. years of runway

Most calculators spit out a number in months. Convert that to years (divide by 12) and compare it to your expected retirement length. If you retire at 65, you'll want your money to last at least to age 90 — that's 25 years, or 300 months. If the calculator says 240 months, you have a gap to close.

### Why small changes in withdrawal rate dramatically shift your timeline

This is the part that surprises most people. Pulling an extra $200 a month doesn't just cost you $200 — it costs you the growth that $200 would have generated over the next decade. A portfolio earning 6% annually behaves very differently depending on whether you're withdrawing 3%, 4%, or 5% of it each year. That difference can translate to a 10–15 year swing in how long your savings survive.

---

## How Long Will Money Last Calculator: Withdrawal Rate Edition

Your withdrawal rate is probably the single biggest lever you control. Everything else — market returns, inflation, taxes — is partly outside your hands. Your spending isn't.

### Setting a sustainable monthly withdrawal amount

A common starting point: take your total savings and multiply by 4%, then divide by 12. That gives you a monthly withdrawal that, historically, has lasted 30 years across most market conditions. On a $600,000 portfolio, that's $2,000 a month. On $1 million, it's about $3,333.

If that number is lower than your actual expenses, you either need more savings, more income from other sources (Social Security, an annuity, part-time work), or a plan to spend less in early retirement.

### Fixed vs. flexible withdrawal strategies compared

| Strategy | How it works | Upside | Risk |
|---|---|---|---|
| Fixed dollar | Withdraw the same amount every month | Predictable budget | Doesn't adjust when markets drop |
| Fixed percentage | Withdraw a set % of current balance | Naturally shrinks in bad years | Variable income month to month |
| Guardrails method | Adjust spending when portfolio crosses thresholds | Balances stability and flexibility | Requires discipline to cut spending |
| Bucket strategy | Segment savings into short/mid/long-term buckets | Protects near-term spending | Complex to manage |

Most retirees do best with some flexibility. Cutting spending by 10–15% in a bad market year can add years to your runway.

### How sequence-of-returns risk shortens your timeline

Here's a scenario that doesn't get enough attention: two retirees with identical portfolios and identical average returns can end up with wildly different outcomes depending on *when* bad years hit. If you get big losses in years one through three of retirement while you're still withdrawing heavily, you lock in those losses permanently. Your portfolio never fully recovers, even if later years are good. This is sequence-of-returns risk, and it's why a calculator showing your "average" return can paint a rosier picture than reality.

---

## How Long Will Retirement Savings Last: Running the Numbers

### How much retirement savings do most people need?

A widely cited rule of thumb: save 10–12 times your final salary by retirement. So if you're earning $80,000, you'd want $800,000–$960,000. Another approach is to figure out your annual retirement spending and multiply by 25 (the inverse of the 4% rule). If you need $50,000 a year, you need $1.25 million saved.

Neither number is magic. Your actual target depends on when you retire, what Social Security pays you, whether you have a pension, and how long your family tends to live.

### Mapping savings to expected retirement length

Here's a rough guide assuming a 5% annual return and no inflation adjustment:

| Savings | Monthly withdrawal | Approximate runway |
|---|---|---|
| $300,000 | $1,500 | ~26 years |
| $500,000 | $2,000 | ~30 years |
| $500,000 | $3,000 | ~17 years |
| $1,000,000 | $4,000 | ~30+ years |
| $1,000,000 | $6,000 | ~20 years |

These are ballpark figures. A real calculator — and especially a real financial plan — will layer in your specific tax situation, Social Security timing, and inflation.

### Using Social Security income to extend your savings runway

Social Security is often the most underutilized piece of the retirement puzzle. Every dollar of guaranteed monthly income from Social Security is a dollar you don't have to pull from savings. If you're receiving $2,000 a month from Social Security and your expenses are $4,500, you only need $2,500 a month from your portfolio — a huge difference in how long that portfolio survives.

Delaying your claim from 62 to 70 increases your monthly benefit by roughly 77%, according to the Social Security Administration. That's a powerful way to buy yourself more runway without touching your savings at all.

---

## How Long Will My Savings Last Calculator With Inflation

### Why inflation is the silent drain on retirement funds

Inflation doesn't feel urgent when it's 3% a year. But over 20 years, it cuts your purchasing power nearly in half. A $4,000 monthly budget today will need to be $7,224 in 20 years just to buy the same things — at a steady 3% inflation rate. If your calculator doesn't account for this, it's giving you an optimistic answer.

### How to adjust your calculator inputs for a 3%–4% inflation rate

When using any retirement calculator, set your inflation assumption at 3%–4% unless you have a strong reason to go lower. Healthcare costs in particular tend to run hotter than general inflation — some estimates put medical cost inflation for retirees at 5%–6% per year. If healthcare is a big chunk of your budget, consider using a higher inflation rate for that line item specifically.

### Real vs. nominal returns: which number to use

This trips people up. Your brokerage statement might show a 7% return — that's the nominal return. Subtract your inflation rate and you get your *real* return, the one that actually reflects purchasing power growth. If you're earning 7% and inflation is 3%, your real return is roughly 4%. Use real return when thinking about how much your purchasing power grows; use nominal return when the calculator handles inflation separately (most do).

---

## How Long Will Money Last Calculator With Taxes

### Tax treatment of 401(k), IRA, and Roth withdrawals

Not all retirement dollars are equal after taxes:

- **Traditional 401(k) / Traditional IRA:** Withdrawals are taxed as ordinary income. Every dollar you pull out adds to your taxable income for that year.
- **Roth 401(k) / Roth IRA:** Qualified withdrawals are tax-free. This is powerful — your calculator number is the number you actually keep.
- **Taxable brokerage accounts:** You pay capital gains tax on gains, not the full withdrawal. Long-term capital gains rates (0%, 15%, or 20%) are typically lower than ordinary income rates.

A $4,000 monthly withdrawal from a traditional 401(k) might net you $3,200–$3,400 after federal taxes. From a Roth, you keep all $4,000. That difference compounds dramatically over a 25-year retirement.

### How required minimum distributions (RMDs) affect your timeline

Once you hit age 73 (under current IRS rules), you must start taking required minimum distributions from traditional 401(k)s and IRAs whether you want to or not. The IRS sets the amount based on your account balance and life expectancy. If your RMD is larger than what you'd otherwise spend, you'll owe taxes on that extra income — and it can push you into a higher bracket or trigger higher Medicare premiums.

### Estimating your effective tax rate in retirement

Most retirees land in a lower tax bracket than during their working years — but not always. Between Social Security income (up to 85% of which may be taxable), RMDs, and any pension income, your taxable income can add up. A reasonable planning assumption for many retirees is a 12%–22% effective federal rate, but this varies widely. When running a retirement calculator, factor in that your gross withdrawals need to cover both expenses *and* taxes.

---

## How Long Will Money Last Using the 4% Rule

### What the 4% rule actually says (and what it doesn't)

The 4% rule comes from the Trinity Study, research from the 1990s that examined historical 30-year portfolio survival rates. The finding: a portfolio of roughly 50–75% stocks and 25–50% bonds could sustain annual withdrawals of 4% of the starting balance — adjusted for inflation each year — for 30 years in nearly all historical scenarios.

What it *doesn't* say: that 4% is safe for 40-year retirements, that it works in all market environments, or that you should blindly follow it regardless of what markets are doing.

### Running a 4% rule calculation step by step

1. Add up all investable retirement savings (401k, IRA, brokerage — not your home equity or emergency cash)
2. Multiply by 0.04
3. That's your first-year withdrawal amount
4. Each year, increase it by your actual inflation rate

Example: $800,000 × 0.04 = $32,000 per year, or about $2,667 per month. Year two, if inflation was 3%, you'd withdraw $32,960.

### When the 4% rule breaks down — low returns, high inflation, long retirements

Three scenarios put pressure on the 4% rule:

- **Low-return environments:** If bonds yield 2% and stocks return 5% for a decade, the math gets tight
- **High inflation:** The 2022–2023 inflation spike reminded everyone that 7–8% inflation does happen
- **Long retirements:** The original research covered 30 years. If you retire at 60 and live to 95, you need a 35-year plan, and the historical success rates drop

Many planners now suggest 3.3%–3.5% as a more conservative floor, especially for early retirees.

---

## How Long Will My 401(k) Last Calculator

### Factoring in 401(k) growth rate during retirement

Your 401(k) doesn't stop growing when you retire — it just grows more slowly because you're pulling money out. The net growth rate (return minus withdrawals) determines whether your balance trends up, stays flat, or declines. A $500,000 401(k) earning 6% and distributing 4% annually has a net growth rate of roughly 2%, which extends its runway significantly.

### 401(k) withdrawal rules at 59½, 72, and beyond

- **Before 59½:** Withdrawals trigger a 10% early withdrawal penalty plus ordinary income tax (with some exceptions)
- **59½ and later:** Penalty-free withdrawals begin; you pay only ordinary income tax
- **Age 73:** RMDs kick in — you must withdraw a minimum amount each year based on IRS tables

If you retire at 65, you have about 8 years of penalty-free, RMD-free flexibility to manage your tax burden strategically.

### Combining 401(k) assets with Social Security and pension income

Think of retirement income in layers. Social Security and any pension form your guaranteed base — income that arrives regardless of what markets do. Your 401(k) and IRA assets sit on top of that base, filling the gap between guaranteed income and actual spending. If your guaranteed income covers 70% of your expenses, your portfolio only needs to cover 30%, which dramatically extends how long it lasts.

---

## Best Retirement Withdrawal Calculators Compared

### Bankrate retirement withdrawal calculator — what it does well

Bankrate's calculator is clean and beginner-friendly. You enter your balance, monthly withdrawal, and expected return, and it shows you a straightforward depletion timeline with a chart. It's a good starting point for a quick gut-check, though it doesn't handle taxes or Social Security offsets natively.

### Fidelity and Vanguard calculator features side by side

| Feature | Bankrate | Fidelity | Vanguard |
|---|---|---|---|
| Tax-adjusted projections | No | Yes | Yes |
| Social Security integration | No | Yes | Yes |
| Inflation adjustment | Basic | Yes | Yes |
| Monte Carlo simulation | No | Yes | Yes |
| Free to use | Yes | Yes (account required) | Yes (account helpful) |

Fidelity's Retirement Income Planner and Vanguard's Retirement Nest Egg Calculator both run Monte Carlo simulations — they don't just show you the average outcome, they show you how often your plan survives across thousands of random market scenarios. That's a much more honest picture than a single straight-line projection.

### When a calculator isn't enough: the case for professional planning

Calculators are excellent for building intuition. They're not a replacement for a real plan. When your situation involves significant tax optimization, pension decisions, Social Security timing strategy, estate planning, or a health event that changes your spending forecast — a fee-only financial planner earns their fee many times over. Use a calculator to understand the levers; use a planner to pull them in the right order.

---

## How Annuities Can Guarantee Your Money Lasts as Long as You Do

### How an annuity solves the 'running out of money' problem

Every retirement calculator has the same Achilles heel: it can tell you the *probability* your money lasts, but not the *guarantee*. An income annuity changes that. You hand an insurance company a lump sum, and they contractually promise to send you a check every month for the rest of your life — no matter how long you live, and no matter what markets do.

It's the only retirement strategy that fully eliminates longevity risk: the risk of outliving your money.

### Comparing annuity income to calculator-projected withdrawals

Suppose you're 65 with $300,000 to convert. A calculator might say that, at $1,500/month, it lasts about 26 years — to age 91. An income annuity on that same $300,000 might pay $1,700–$2,000/month for life, depending on current rates and your health. If you live to 95, the annuity keeps paying. The calculator-based drawdown would have run out four years earlier.

The trade-off: with an annuity, the principal is generally gone. You're trading flexibility for certainty. That's why most planners recommend annuitizing enough to cover basic expenses — housing, food, healthcare — and keeping the rest invested for flexibility and growth. If you're shopping for guaranteed income options, getting a free annuity quote takes only a few minutes and can show you exactly what your balance could generate monthly.

### Who should consider adding an annuity to their retirement plan

An annuity makes the most sense if:

- Your Social Security and pension income don't fully cover your essential expenses
- You're worried about living well into your 90s (longevity runs in your family)
- You want to simplify retirement: fewer decisions, guaranteed income, less market anxiety
- You have a specific savings bucket — say, an old 401(k) from a previous employer — that could be converted into a reliable income stream

It makes less sense if you're in poor health, have very limited savings, or need maximum flexibility for near-term large expenses.

---

## Frequently Asked Questions

## How do I calculate how long my money will last in retirement?

Start with your total savings, subtract any guaranteed income (Social Security, pension) from your monthly expenses, and divide your savings by that net monthly gap. That gives you a rough month count. For a more accurate picture, use a calculator that factors in investment returns — your money keeps growing even as you draw it down — plus inflation and taxes.

## How long will $500,000 last in retirement with $3,000 monthly withdrawals?

At $3,000 per month ($36,000/year) with a 5% annual return and no inflation adjustment, $500,000 lasts roughly 17–18 years. If you retire at 65, that takes you to about age 82–83 — shorter than many people live. Adding Social Security income to offset part of that $3,000 need could stretch it significantly further.

## What is a safe withdrawal rate in retirement?

The classic answer is 4%, based on the Trinity Study's historical research. Many planners now suggest 3.3%–3.5% for retirements longer than 30 years or in lower-return environments. The "safe" rate depends on your portfolio mix, other income sources, flexibility to cut spending, and how long you expect to live.

## How does inflation affect how long my retirement savings last?

Inflation silently erodes purchasing power. At 3% annual inflation, your expenses double roughly every 24 years. A calculator that ignores inflation will tell you your money lasts longer than it actually will — because each dollar you withdraw covers less and less over time. Always set your inflation assumption to at least 3% in any retirement calculator.

## How long will my 401(k) last if I retire at 65?

It depends on your balance, withdrawal amount, and return. A $600,000 401(k) with a 5% return and $2,500/month in withdrawals lasts roughly 29–30 years, taking you to about 94–95. Factor in RMDs starting at 73, which may force larger withdrawals than you planned, and set aside roughly 20%–25% of each withdrawal for federal and state income taxes.

## Is the 4% rule still a reliable retirement guideline?

It's a reasonable starting point, not a law. The original research assumed a 30-year retirement and historical U.S. market returns. In low-yield environments or for retirements stretching to 40 years, many experts suggest a more conservative 3.3%–3.5% withdrawal rate. Used alongside Social Security and other income, the 4% rule remains a useful framework — just not a guarantee.

## Can an annuity guarantee my money lasts as long as I live?

Yes — that's the defining feature of a lifetime income annuity. In exchange for a lump sum, an insurance company guarantees monthly payments for as long as you live. Whether you live to 82 or 102, the check keeps coming. No drawdown strategy from a calculator can make that promise, which is why [annuities](/annuities/) are often used to cover essential expenses as a guaranteed floor.

## Do I have to pay taxes on retirement account withdrawals?

It depends on the account type. Traditional 401(k) and IRA withdrawals are taxed as ordinary income — you'll owe federal (and often state) income tax on every dollar. Roth 401(k) and Roth IRA qualified withdrawals are tax-free. Withdrawals from taxable brokerage accounts are subject to capital gains tax, typically at lower rates than ordinary income. Always factor taxes into your withdrawal math; a $4,000 gross withdrawal from a traditional 401(k) might net only $3,200–$3,400 after taxes.