[rnprince]

Edit: there's a correction on this in the child comments.

The math on this is misleading. $10k invested for 30 years to become $1M implies an interest rate of 16.6%. Even as a nominal interest rate in the US, that would be an extremely lucky result to consistently achieve. My advice to you would be to start a hedge fund immediately with whatever secret knowledge you have, and then all money concerns will become irrelevant. :-)

A good choice for a real ('real' meaning non-nominal) interest rate in these types of projections is 7%, which would make $10k equal to $76k in 30 years. Because you used a real interest rate, the $76k is $76k in today's dollars, not in 2047 dollars. The conclusion is that you will need to invest a bit more than $10k today to retire in 30 years.

I like to use this type of calculation to frame my short-term purchase decisions. Would I like to spend $20 on this thing I don't need? Yes. Would I like to spend today's equivalent of $300 on it 40 years from now? No thank you.

[Twisol]

The parent also mentioned adding to the funds on a monthly basis. Does that make the math match up more properly?

[rnprince]

Yes, it does. I missed that. :-)