How to turn 100 a month into 100,000
A hundred a month is small enough that almost anyone can start, which is what makes this the most useful calculation on the site for beginners. At 9% it reaches 100,000 in roughly twenty-eight years - and you will only have deposited about a third of that.
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Two thirds of it is not your money
Depositing 100 a month for twenty-eight years puts in 33,600. The remaining 66,000 or so is growth. That ratio is the entire argument for starting early with a small amount rather than waiting to start with a large one.
Raise the monthly figure to 150 and the target arrives roughly five years sooner. Raise it to 200 and it is about nine years sooner.
Starting is the hard part
The first two years feel pointless: the balance is small and growth is invisible. That period is unavoidable and it is where most plans are abandoned.
Automating the transfer on payday is the single most effective habit here, because it removes the monthly decision entirely.
Frequently asked questions
How long does 100 a month take to reach 100,000?
About twenty-eight years at 9%, or thirty-two at 7%. Adjust the rate above to see the difference.
Is 100 a month worth investing?
Yes. It builds the habit and captures decades of compounding, and the habit is usually worth more than the amount.
Where should I put it?
Most beginners use a low-cost diversified index fund inside a tax-advantaged account where one is available.
What if I miss some months?
The plan slips rather than breaks. Restart and, where possible, raise the amount slightly to make up ground.
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