Retirement can seem very far away when you're young. Unfortunately, because of this, many people who are just starting out don't save enough for it.

Saving too little early on can make it much harder to catch up later as you lose out on years of compound interest. That's likely why so many older Americans wish they hadn't waited. In fact, the number one piece of advice people in their 40s, 50s, 60s, and 70s would give their younger selves is to start saving sooner, according to a recent TD Ameritrade survey

A full 68% of all survey respondents would admonish their younger selves to sock away more cash, the survey showed. And the older people get, the more they wish they'd started saving ASAP. That's why 69% of people in their 60s and 75% of people in their 70s would give this advice. 

Older woman with clasped hands looking worried.

Image source: Getty Images.

Why does starting young matter so much?

When you start saving early, invested funds begin earning returns right away. The money your investments earn can be reinvested so you'll earn a return on that cash too. When you earn interest on interest, it's called compound interest and it can help your account balance to grow quickly. 

You can invest a much smaller amount to end up with a larger nest egg if you begin saving when you're young and compound interest has decades of time to work for you.

Consider the table below, which shows how much a $250 monthly investment earning an 8% annual return would net you by 65, depending on the age you start saving. 

Age You Start Investing

Amount You Have at 65

20

$1,320,000.00

25

$872,776.00

30

$573,486.00

35

$372,600.00

40

$237,763.00

45

$147,260.00

50

$86,512.00

55

$45,738.00

Table calculations: Author

Looking at this table, it should come as no surprise that someone in their 40s or beyond would wish they'd started saving sooner. If you save the same monthly amount but start at 25 instead of 45, you'd have over $1 million more invested by the time you're ready to retire.

If you start with nothing at 45 and want to end up with that same $1.32 million, you'd need to invest $2,235 per month -- an impossible sum for most people.

Start saving ASAP so you don't have any regrets

You don't want to become one of the majority of older Americans wishing they could tell their younger selves to start saving more money earlier. And while you can't invest in a time machine to go back and start putting away money in your 20s, you'll never again be as young as you are today. That makes today the perfect day to increase the amount you're investing for the future. 

Sit down with your budget, look for ways to cut spending, and figure out what you can sock away if you prioritize savings. Then increase your 401(k) or IRA contributions until you're satisfied you're on track and not letting your future self down. 

By getting serious about saving today, you can avoid future regrets about waiting too long to get started.