Guide · Updated September 2026
Leer en españolHow much to save a month to reach $100k, $500k or $1M
The monthly amount for common goals over 10 to 40 years, why starting early beats saving more, and what inflation does to the result.
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The answer depends on three things: your target, how many years you have and the return you assume. Here is the monthly amount needed to reach common goals, starting from zero, assuming a 7% average annual return compounded monthly.
| Goal | 10 years | 20 years | 30 years | 40 years |
|---|---|---|---|---|
| $100,000 | $578 | $192 | $82 | $38 |
| $250,000 | $1,444 | $480 | $205 | $95 |
| $500,000 | $2,889 | $960 | $410 | $190 |
| $1,000,000 | $5,778 | $1,920 | $820 | $381 |
The pattern is the whole lesson: every extra decade roughly cuts the monthly amount by more than half. $1 million in 40 years takes $381 a month. In 20 years it takes $1,920.
Why time matters more than the amount
Take $300 a month at 7%:
- Over 30 years it grows to about $366,000. You put in $108,000.
- Over 40 years it grows to about $787,000. You put in $144,000.
Ten more years and $36,000 more in contributions more than doubles the result, because the last decade of growth happens on a much larger balance. Starting early beats saving more later, for most people.
Don't forget inflation
A dollar in 30 years will buy less than a dollar today. At 3% inflation, $1,000,000 in 30 years has the buying power of about $412,000 today. Our compound interest calculator shows both numbers. If you want $1 million in today's money, use a lower return in the math (7% minus 3% inflation is roughly 4%) or a bigger target.
Where 7% comes from, and why it may be wrong
7% is a common planning assumption for a stock-heavy long-term portfolio. It is not a promise. Real returns vary a lot from year to year and decade to decade, and fees and taxes reduce what you keep. A more conservative plan uses 5% or 6%. At 5%, reaching $1,000,000 in 30 years takes about $1,202 a month instead of $820.
Savings accounts and CDs pay much less over long periods, so the table only applies to money invested for growth, not your emergency fund.
Make the number smaller
- Count what you already have. Existing savings shrink the monthly amount a lot, since they compound too.
- Raise contributions with your pay. Increasing your monthly amount by a few percent each year can close a big gap without a painful start. The calculator has a field for that.
- Use employer matches first. A match is part of your contribution that you do not pay for.
- Automate it the day after payday, so saving happens before spending.
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Questions
How much do I need to save a month to have $1 million?
At a 7% average annual return, starting from zero: about $5,778 a month for 10 years, $1,920 for 20 years, $820 for 30 years or $381 for 40 years. Returns are not guaranteed.
Is 7% a realistic return?
It is a common long-term planning assumption for a stock-heavy portfolio, not a guarantee. Use 5% or 6% for a more conservative plan.
How does compound interest work?
Your returns earn returns. Each month, growth is added to your balance, and next month's growth is calculated on the larger balance.
Should I account for inflation?
Yes. A future dollar buys less. At 3% inflation, $1 million in 30 years is worth about $412,000 in today's money.
Educational content, not financial, tax, legal or investment advice. Examples use made-up numbers. Check rates, taxes and loan terms with your own sources.