This simple chart reveals how much you need to save at 35 to become a millionaire by 65

If you’re in your 30s and already dreaming of retirement, you may be wondering: Just how much do I need to start socking away to retire? That, of course, depends on what your spending will be like in retirement, your rate of return, your lifestyle and more. If you just head all that and thought, sigh, I don’t know any of those factors, that’s understandable. So let’s just take it down to the simplest level — how to hit $1 million by a certain age.

How much you need to save, by age, each month to become a millionaire at 65

Your next question, of course, is how do I get a 6% rate of return? There’s not a guarantee of that, but historically the stock market has returned an average of 10% for about the last century. (Though it’s important to keep in mind that in many years returns look nothing like this, and returns are reduced by inflation.)

As for how you should invest, Tiffany Lam-Balfour, investing spokesperson for NerdWallet, says it depends on your personal financial situation, goals, risk tolerance and time horizon. “If retirement at 65 is the goal, generally you’ll be more aggressive the younger you are since you’ll have a longer time horizon. Over time, as retirement draws near, you would gradually shift your allocation toward a less risky, more conservative allocation, like adding in more stable assets such as fixed income, bonds and cash equivalents into your portfolio. However, even in retirement, your portfolio should still maintain an allocation to stocks to help your assets continue to grow and keep up with inflation,” says Lam-Balfour.

At 35, Greg McBride, chief financial analyst at Bankrate says, “Your retirement account allocation is still going to be quite aggressive and not too different from what you had at 25, as you’re likely still 30 years away from retirement.”

McBride also underscores the power of compounding. “Compounding works best when you can compound the higher rates of return that come with investing in a broad stock market index fund. The long time horizon and years of additional contributions mean you can allocate heavily toward stocks without worry about short-term volatility impacting your long-term plans,” says McBride.

That said, another point of caution is this: “This $1 million would not have the same buying power as $1 million today because of inflation,” says McBride. In other words, you may want to aim higher. Here are five questions to ask yourself to figure out how much money you might need to retire.

And Priya Malani, CEO of Stash Wealth, says playing catch up sucks. By starting early, you don’t have to save as much to achieve the same result. “It’s pretty simple—you should invest in the asset allocation that creates the returns you need to achieve your desired outcome,” says Malani.