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The Complete Guide to Retirement Planning

Retirement planning is really two problems: accumulating enough, and not running out once you stop working. Most guides focus almost entirely on the first — but the decumulation phase is where mistakes are both most common and least recoverable.

Written by Jere Salmisto·Reviewed by CalcFi Editorial·Last verified: 2026-05-13
TL;DR

Retirement planning is really two problems: accumulating enough, and not running out once you stop working. Most guides focus almost entirely on the first — but the decumulation phase is where mistakes are both most common and least recoverable.

This guide covers the full retirement arc. Whether you are 25 and want to retire at 40 under FIRE principles, 45 and playing catch-up, or 60 and trying to optimize Social Security claiming, the math that governs your outcome is the same.

Throughout, we link to the specific calculators that let you pressure-test assumptions — returns, inflation, tax brackets, withdrawal order — instead of relying on a single "retirement score" number that hides every interesting tradeoff.

In this guide

  1. 1. Figuring Out Your Retirement "Number"
  2. 2. Choosing the Right Accounts
  3. 3. Social Security and Decumulation
  4. All calculators in this guide
  5. Frequently asked questions

1. Figuring Out Your Retirement "Number"

The classic rule is 25× your annual spending: if you need $60,000/year, you need roughly $1.5M. This comes from the "4% rule" Trinity Study, which found a 4% initial withdrawal (adjusted yearly for inflation) survived 30-year retirements in nearly all historical periods.

FIRE (Financial Independence, Retire Early) tightens this to 3.25–3.5% because the retirement horizon stretches to 50+ years, and Coast FIRE flips it: save aggressively until compound growth alone covers you by age 65.

Start with actual spending, not replacement-rate shortcuts. Most planners use 70–80% of pre-retirement income, but retirees often spend more in the first decade (travel, healthcare) and less later — a "go-go, slow-go, no-go" pattern.

FIRE Number Calculator
Your retirement target using the 25× rule.
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FIRE Timeline Calculator
Years-to-FIRE based on savings rate.
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Coast FIRE Calculator
How much to save now to coast to retirement.
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Retirement Savings Calculator
Projected balance at retirement age.
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2. Choosing the Right Accounts

The order of account usage matters nearly as much as the amount saved. The standard hierarchy: 401(k) up to the employer match, then max a Roth or traditional IRA, then back to the 401(k) up to the annual limit ($23,500 in 2025, plus $7,500 catch-up at 50+).

Roth vs. traditional comes down to your current tax bracket versus your expected retirement bracket. Young, lower-income workers almost always favor Roth; higher earners in their 40s and 50s often lean traditional to get the deduction now.

The Mega Backdoor Roth and Backdoor Roth strategies allow high earners to move $30,000–$70,000 per year into Roth space, bypassing income limits entirely. They are underused because they are poorly explained.

401(k) Contribution Calculator
Maximize match and annual limit.
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Roth IRA Calculator
Tax-free growth projection.
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Roth vs. Traditional IRA
Which saves you more after taxes.
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Backdoor Roth Calculator
Roth strategy above the income limit.
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Mega Backdoor Roth
After-tax 401(k) to Roth conversion.
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HSA Calculator
Triple-tax-advantaged medical savings.
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3. Social Security and Decumulation

Every year you delay claiming Social Security past age 62 raises your benefit by 7–8%, up to age 70. That is a historically reliable, inflation-adjusted return no other asset can match.

The catch: you need a bridge strategy to fund spending between retirement and your claiming age. Roth conversions during those gap years are often the single highest-impact decision a retiree makes.

Required Minimum Distributions (RMDs) start at age 73, forcing taxable withdrawals even if you do not need the money. Planning for RMDs at 60 — by Roth-converting strategically — can cut six-figure amounts from your lifetime tax bill.

Social Security Optimizer
Optimal claiming age and strategy.
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RMD Calculator
Required minimum distributions by age.
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Required Minimum Distribution
IRS RMD schedule.
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Early Retirement Withdrawal
Rule of 55 and 72(t) planning.
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Inherited IRA Calculator
10-year drawdown rules.
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All Calculators in This Guide

FIRE Number
Your financial-independence target
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FIRE Timeline
Years to FIRE by savings rate
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Coast FIRE
Save less, coast later
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Retirement Savings
Projected balance at retirement
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401(k) Contribution
Max match and annual limit
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Roth IRA
Tax-free growth projection
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Roth vs Traditional
Bracket-based comparison
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Backdoor Roth
High-income Roth strategy
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Mega Backdoor Roth
After-tax 401(k) conversion
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HSA
Triple-tax-advantaged savings
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Social Security Optimizer
Best claiming age
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RMD
Required withdrawals
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RMD (IRS schedule)
Official RMD table
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Early Withdrawal
Rule of 55, 72(t)
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Inherited IRA
Beneficiary rules
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Self-Employed Retirement
Solo 401(k), SEP, SIMPLE
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NUA Strategy
Employer stock in 401(k)
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Frequently Asked Questions

How much do I need to retire?+

A common benchmark is 25× your annual spending — so $60k/year needs about $1.5M invested. Adjust down for Social Security and pensions, up for early retirement.

Should I max my 401(k) or IRA first?+

Capture the full 401(k) match first, then max an IRA, then return to the 401(k). The match is an instant 50–100% return.

Is a Roth or traditional better?+

Roth wins if your current tax bracket is lower than your expected retirement bracket. Traditional wins if the opposite. Most 20s-30s workers should tilt Roth.

What is the 4% rule?+

Withdraw 4% of your portfolio in year one, then adjust that dollar amount by inflation each year. Historically, this lasted 30+ years in nearly every market scenario.

When should I claim Social Security?+

If you expect average or better longevity and can afford to delay, waiting to 70 increases lifetime benefits by roughly 77% versus claiming at 62.

What is Coast FIRE?+

Saving enough by a certain age that compound growth alone covers retirement, with zero new contributions needed. You "coast" to 65.

Are RMDs avoidable?+

Not on traditional IRA/401(k) balances after 73, but Roth IRAs have no RMDs, so strategic Roth conversions in your 60s can shrink future RMDs dramatically.

Can I retire before 59½ without penalty?+

Yes, via Rule of 55 (from an active 401(k)), 72(t) Substantially Equal Periodic Payments, or a Roth conversion ladder.

Do I need an HSA if I have a 401(k)?+

HSAs are the most tax-advantaged account in the US code (triple-tax-free if used for medical). Max an HSA before a second non-match 401(k) dollar.

How does inflation affect retirement planning?+

A 3% inflation rate halves purchasing power in 24 years. Your withdrawal plan must index to inflation, and your portfolio must include inflation-sensitive assets.

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