Retirement is something that many of us dream about and really look forward to. But if we're not planning for it well and being good savers and investors, our golden years can end up less wonderful than we'd hoped.

One way to get on track -- and stay on track -- is to gaze with rapt attention at the most important retirement chart you'll ever see.

Yellow road sign that says "Retirement ahead"

Image source: Getty Images.

The most important retirement chart

What makes this chart so important? Well, the chart is vital because it shows you, at a glance, just how much money you can accumulate over time for retirement. Check it out below:

Growing at 8% for...

$5,000 Invested Annually

$10,000 Invested Annually

$15,000 Invested Annually

5 years

$31,680

$63,359

$95,039

10 years

$78,227

$156,455

$234,682

15 years

$146,621

$293,243

$439,864

20 years

$247,115

$494,229

$741,344

25 years

$394,772

$789,544

$1.2 million

30 years

$611,729

$1.2 million

$1.8 million

35 years

$930,511

$1.9 million

$2.8 million

40 years

$1.4 million

$2.8 million

$4.2 million

Data source: Calculations by author.

Like many great charts, it's versatile. You can see how much you'll end up with in retirement if you save a relatively modest sum ($5,000) annually or a more aggressive sum ($15,000), or something in between ($10,000). Double the numbers in the $10,000 column and you'll see what annual savings of $20,000 can do for you.

How to save large sums annually

Of course, socking away thousands of dollars each year can seem very difficult or impossible to most people. Fear not, though, because there are ways to do it.

I've written earlier about 40 tips for saving money. If you employ just 10 of them and save $100 with each, that's $1,000 in annual savings. (Some can save you hundreds on their own.) Here are a few of those ideas:

  • Just an hour or two spent making phone calls to your insurance companies can yield hundreds of dollars per year in savings. Every year or two, shop around for better insurance rates for your home insurance, car insurance, umbrella insurance, renter's insurance -- perhaps even your health insurance. Each insurer uses different formulas to determine its rates, and at any given time, each probably will offer you a different price for the same coverage. Remember, too, that you can often save more by having two or more policies with the same insurance company.
  • You can save a lot, obviously, if you cut back on eating out at restaurants. But if you don't want to go that far, consider cutting back on drinks ordered out. If you opt for water instead of a $3 soda or coffee -- or a $5 beer, a $7 wine, or a $10 mixed drink -- you can save some meaningful dollars, and they can really add up. If you typically buy two mixed drinks when dining out once a week, that's $20; times 52 weeks, it's more than $1,000 per year. Cut back to just one drink, and you could save $500. Buying five beers a week at $5 each comes to $1,300. Spend a little time determining just how much you're forking out for beverages and how much you might want to save by cutting back.
  • More and more people each year give up cable TV. The average cable and satellite TV bill was recently around $101, for a total of about $1,200 annually. If you stop spending that and just stream your video entertainment instead, via one or more streaming services, you can save quite a bit. For example, Netflix charges between $8 and $14 per month, while Hulu charges between $8 and $12; an Amazon Prime subscription costs $119 per year, or about $10 per month. Those three together can give you more than you could ever watch for $36 or less per month. And there are lots of other streaming services you might want to research.
Two red dice, near a torn piece of paper reading "Have you saved enough?"

Image source: Getty Images.

What your savings will give you in retirement

It's valuable to put that most important retirement chart in context, to see what it can actually do for you. A handy tool for that purpose is the flawed, but still helpful, 4% rule. It suggests that you withdraw 4% of your nest egg in your first year of retirement, and adjust future withdrawals for inflation. Thus, if you accumulated the $789,544 above over 25 years, you could take out $31,582 in your first year.

Here's the table above, tweaked to show you the income that each total would give you in your first year of retirement:

Growing for...

4% of Ending Total -- $5,000 Invested Annually

4% of Ending Total -- $10,000 Invested Annually

4% of Ending Total -- $15,000 Invested Annually

5 years

$1,267

$2,534

$3,802

10 years

$3,129

$6,258

$9,387

12 years

$4,099

$8,198

$12,297

15 years

$5,865

$11,730

$17,595

20 years

$9,885

$19,769

$29,654

25 years

$16,000

$31,582

$48,000

30 years

$24,000

$48,000

$72,000

Data source: Calculations by author.

If the sums above still don't seem like enough to you, remember that you're likely also to have some Social Security income to look forward to. The average Social Security retirement benefit recently was $1,413 per month, or about $17,000 per year. You might well collect more, though, and there are also ways to increase your Social Security benefits. (By the way: Here's the most important Social Security chart you'll ever see.)

John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Selena Maranjian owns shares of, and The Motley Fool owns shares of and recommends, AMZN and NFLX. The Motley Fool has a disclosure policy.