Get an estimate of your savings at retirement age. Also see your year-by-year income forecast—or, if applicable, your income shortfall.
Best Features: The tool works for singles and both married and unmarried couples. Annual income is broken down by source.
Be Aware: Default life expectancy ages are 84 for men and 87 for women. You’ll have to estimate your Social Security income. aarp.org/calculators

Plug in your current and planned savings to get a quick idea of whether they’ll be sufficient for your desired standard of living.
Best Features: Sliders controlling several variables, such as age of retirement and annual savings, give you instant feedback showing whether, and how quickly, you might run out of money.
Be Aware: Social Security estimates, which can’t be adjusted, are based on out-of-date FICA (Federal Insurance Contributions Act) and benefit numbers, and the calculation assumes that only one spouse in a marriage has earned retirement benefits. bankrate.com/calculators

Get answers to questions such as when you can retire, what your income will be and how your net worth will change annually.
Best Features: Ability to handle several complexities other planners don’t, such as the different tax treatments of traditional and Roth IRAs and the effect of claiming Social Security later than your retirement date.
Be Aware: It may take 10 to 20 minutes to set up the planner and a few hours or longer to get the most out of it.
Also Check Out: PlannerPlus ($120/year), which adds many more features, such as precise modeling of Medicare expenses. The Simple Retirement Calculator takes less than a minute to estimate how long your money will last. boldin.com

Answer six simple questions and see whether your retirement planning is On Target, Good, Fair or Needs Attention.
Best Features: Simplicity and speed
Be Aware: The Retirement Score is just for one person, not a couple.
Also Check Out: Retirement Strategies Tax Estimator, which higher-income taxpayers can use to estimate the tax impact of Roth IRA conversions, charitable giving and retirement savings withdrawals. fidelity.com/calculators

Get an estimate of the dollar amount you’ll have upon your expected retirement age, and see how long it will last based on your standard of living.
Best Features: Easy inputs and instant feedback on how changes to your assumptions will affect your financial outcome.
Be Aware: You’ll have to input Social Security income, and you’ll have to figure out for yourself your after-tax retirement income. nerdwallet.com/calculator/retirement-calculator

Spend a few minutes answering questions about your salary, savings and hoped-for retirement income to get an estimate of how much “extra” savings you’ll have upon retiring or how much you’ll come up short.
Best Features: Clear formats for inputting data and helpful guidance on how to answer questions about your investment style.
Be Aware: The calculator is designed for individuals, not couples; changing inputs doesn’t update results automatically.
Also Check Out: Roth IRA Conversion Calculator, which shows the tax consequences of converting a traditional IRA to a Roth IRA. schwab.com/financial-planning/tools

A fill-in-the-blank tool lets you quickly estimate how much you’ll be able to spend monthly in retirement and how that matches up to your desired spending.
Best Features: Quick answers
Be Aware: There’s not much nuance—no inputs for tax treatment of savings, for example. You have to supply your own benefits estimate for Social Security.
Also Check Out: Retirement Expenses Worksheet, which lets you put in best guesses for retirement spending. investor.vanguard.com/tools-calculators

The Social Security calculator provides a quick rough estimate of benefits based on your date of birth and current salary.
Keep in Mind: The tool links to AARP’s free online Social Security resources. aarp.org/calculators

Based on your date of birth, the Social Security benefit calculator provides your full retirement age (FRA) and estimates your benefit at that age. You can see claiming strategies for you and your spouse, and get claiming strategies if you’re widowed or divorced.
Keep in Mind: As with other calculators able to estimate your benefits, you’ll get more accurate projections and claiming strategies by entering Social Security’s estimate based on your actual earnings history. To get that number, go to ssa.gov/myaccount and set up or access your My Social Security account. fidelity.com/calculators

This $49/year software package from Boston University economics professor Laurence Kotlikoff runs through more than 1,000 possible claiming strategies, producing a detailed report spotlighting top recommendations for you.
Keep in Mind: You’ll need to put in at least 30 minutes with the program to make full use of it. maximizemysocialsecurity.com

This free calculator from CPA Mike Piper, author of Social Security Made Simple, displays a color-coded graph showing the desirability of alternate Social Security claiming strategies for you. It can run numbers for you as a couple or as an individual who is widowed, divorced or disabled. It can also estimate your reduction in benefits if the Social Security trust fund is depleted.
Keep in Mind: This is suited for people who aren’t put off by financial jargon such as “present value.” It works best with a Chrome browser. opensocialsecurity.com