Down Payment Savings Calculator
Calculate how long it will take to save for a home down payment and what monthly savings you need.
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How to use this calculator
Each month the current balance earns interest at the monthly rate (annual rate ÷ 12), then the monthly savings amount is added. This compounds until the balance reaches the down payment target.
- 1
Enter your target home price and the down payment percentage you are aiming for (typically 10–20%).
- 2
Input how much you have already saved and how much you can set aside each month toward the goal.
- 3
Set the expected annual return on your savings account or investment to see how compound interest accelerates your timeline.
Frequently asked questions
What formula does this tool use?
This tool uses target = home price × down payment % ÷ 100, and a month-by-month loop: balance = balance × (1 + annual return ÷ 12) + monthly savings, repeated until the balance reaches the target. With a $400,000 price, 20%, $20,000 saved, $1,000 a month and 4.5% it takes 51 months, ending at $80,294.
When is the monthly contribution added?
Each month the existing balance earns interest first, and then the contribution is added, so a deposit starts earning in the following month. The loop stops in the first month where the balance is at least the target, which is why the final balance usually overshoots the target slightly, as in the $80,294 against $80,000 above.
What if I have already saved enough?
If current savings are at or above the target, the time shows “Already saved!”, months are 0, contributions and interest are $0 and the total equals your current savings. The still-needed line shows $0.
What happens with a return of 0% or no monthly savings?
A return of 0 is valid: the balance just grows by your monthly amount, so $200,000 at 20% from zero with $500 a month takes 80 months (6 years 8 months). If neither interest nor savings can ever reach the target, the loop stops at 600 months and the result reads “Not reached within 50 years”.
How are “interest earned” and “total contributed” worked out?
Total contributed is monthly savings × months, and does not include your starting balance. Interest earned is the final balance minus starting savings minus total contributed, never below zero. The return is a constant nominal annual rate divided by 12; it is not taxed and has no fees or market ups and downs.
Does the tool include closing costs or rising house prices?
No. The target is a fixed percentage of the price you enter. It does not add closing costs, moving costs or reserves, and it assumes the price stays the same during the saving period. If you expect the price to rise, enter a higher price. What percentage a lender or program requires varies by country, loan type and lender, so check before choosing the percentage.
Is the result in years and months?
It is shown in whole years and months, with the exact month count on its own line. 51 months is “4 years 3 months”. Partial months are not shown; the count is the first full month in which the target is met.
Saving for a down payment: months to the target balance
The monthly loop
The tool first converts the price and percentage into a target amount. It then simulates saving one month at a time. Each month the balance grows by one twelfth of the annual return and your monthly savings are added, and the loop ends in the first month the balance reaches the target. The month count becomes the time to goal, total contributions are monthly savings times months, and interest is whatever growth is left once your savings and contributions are taken out. A hard stop at 600 months prevents endless loops.
Worked examples: defaults and a smaller purchase
The defaults ($400,000 price, 20%, $20,000 saved, $1,000 a month, 4.5% return) set a target of $80,000 and take 51 months, or 4 years 3 months. You contribute $51,000, earn $9,294 of interest and end with $80,294. A $300,000 home at 10% with $5,000 saved and $800 a month has a $30,000 target; at 0% it takes 32 months with $25,600 contributed, and at 4% it takes 30 months, with $24,000 contributed, $1,722 of interest and $30,722 at the finish.
How the percentage changes the timeline
The table keeps a $500,000 price, $20,000 of starting savings, $1,000 a month and 4.5% fixed, and changes only the down payment percentage. Doubling the percentage from 5% to 10% more than doubles the time, because each extra step needs a larger balance. These are the tool’s results for the stated inputs and not a recommendation about what percentage to aim for.
| Down payment | Target | Time to goal | Months | Interest earned | Balance at goal |
|---|---|---|---|---|---|
| 5% | $25,000 | 5 months | 5 | $415 | $25,415 |
| 10% | $50,000 | 2 years 3 months | 27 | $3,485 | $50,485 |
| 20% | $100,000 | 5 years 6 months | 66 | $14,332 | $100,332 |
Edge cases
If your balance already meets the target, the tool says so and shows zero months. If monthly savings and the return are both zero and you are below the target, the result reads “Not reached within 50 years” at 600 months. With a $500,000 home, 20% target, $100,000 saved and no further deposits, the target is met at once, so the time shows “Already saved!” even at a 3% return.
What to add yourself
Closing costs, moving costs, reserves and price changes are outside the model. The return is a steady nominal rate, so a real savings account or investment can differ. Rerun with a lower return or a higher price to see how sensitive the timeline is, and check which percentage your lender or loan program actually needs before you set the target.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →