Here's how much money you should have saved by 35

Young people aren't saving enough for the future.

Millennials, or those born between 1981 and 1998, hold only about $2,400 in median total savings, according to a recent survey from MagnifyMoney. That's not going to get you very far, considering that experts say you should have at least three to six months' worth of living expenses in an emergency fund and also be on your way to saving $1 million for retirement.

Luckily, there's still time to catch up. Here's how much you should have saved by age 35 and what to do if you're not on track.

Fidelity, the nation's largest retirement-plan provider, recommends having the equivalent of twice your annual salary saved. That means, if you earn $50,000 per year, by your 35th birthday, you should have around $100,000 socked away.

These should be funds you've allocated for the future, including anything in a retirement account such as a 401(k) or Roth IRA and any company match. You can also include other amounts you have in long-term investments in index funds or with robo-advisers.

To get to that number, Fidelity recommends saving 15 percent of your annual income between what you put away and what percentage, if any, your employer matches. And make sure to invest these funds instead of leaving them in a traditional low-interest savings account. "If you only saved money in an account that got no return, you'd have to save a lot more to reach your goal," Meghan Murphy, a VP at Fidelity, tells CNBC Make It.

"If you want to live a lavish life in retirement, you may want to save a little bit more," Murphy adds, but "if you're perfectly content hanging out at home in retirement, you may need to save a little bit less."

And if you're years or decades away from retirement age, it's okay if you aren't able to contribute a full 15 percent. "It's something to work towards over time," Murphy says. "Always make sure you're getting that company match, then try to increase your savings by 1 percent annually until you reach that 15 percent."

Experts advise that you build up an emergency fund that could cover at least three-to-six months of living expenses.

Emergency funds can cushion the blow if you're struck by financial disaster, says best-selling author Dave Ramsey. Since something is always bound to go wrong, having money on hand will help.

"Car blows up. Transmission goes out. You bury a loved one. Grown kids move home again. Life happens, so be ready," Ramsey writes in "The Total Money Makeover." "This is not a surprise."

Suze Orman, personal finance expert and best-selling author of "Women & Money," agrees, though she recommends being even more prepared. "You need as much money in the bank that makes you feel secure," she says.

"Don't go fooling yourself, 'It's okay, I can charge on a credit card, I can do this.' You should have at least eight months," she says. "Not six months, not three months. I'd like to see you have eight months to one year."

If you're in your 20s or 30s, your money still has decades to grow. "The younger you are, the more time you have to make up for lost time," Murphy says.

But, while it's advantageous to start early, if you're in your mid-30s and only have a paltry amount put away, don't panic. At this point, "the best thing you can do is to set a goal," Murphy says. "It may not be, 'I'll have three times my income by the time I'm 40,' but maybe it's 'I'm going to do what I need to do to have twice my income.' Sometimes that is a matter of making a few changes to how you spend your paycheck."

If you aren't sure the best way to catch up, don't be afraid to ask an expert. "There is a wealth of knowledge available through employers, through financial experts, checklists, and simple ways to help people start thinking about it," Murphy says.

Saving, and saving for the future especially, can feel like making a dentist appointment: "It's something people don't want to think about, so they tend to put it off," Murphy explains. "But the longer you put it off, the harder it's going to be. So start early and ask lots of questions."

Like this story? Subscribe to CNBC Make It on YouTube!

Don't miss: Here's how much money you should have saved by 50