About the Down Payment Calculator
Before you can get a mortgage, you need a down payment - and figuring out how much to save and how long it'll take is often the first real step toward buying a home. Our Down Payment Calculator turns your home price target and savings rate into a concrete timeline.
How It Works
The calculator multiplies your target home price by your chosen down payment percentage to find the total needed, subtracts what you've already saved, and divides the remaining amount by your monthly savings rate to estimate how many months until you reach your goal.
Formula & Methodology
This is a straightforward savings-goal projection, but the down payment percentage you target has an outsized effect on both the goal amount and the resulting mortgage - a lower down payment reaches the goal faster but typically means PMI and a larger loan amount, while a higher down payment takes longer to save but avoids PMI and lowers the monthly mortgage payment going forward. The calculation itself doesn't account for that trade-off; it simply projects the timeline for whatever target percentage you choose.
Step-by-Step: Calculating It By Hand
- 1Multiply your target home price by your down payment percentage to find the total dollar goal.
- 2Subtract what you've already saved toward that goal.
- 3Divide the remaining amount by your monthly savings contribution to find the number of months needed.
- 4Adjust the down payment percentage or monthly savings rate to see how each changes the timeline.
Examples
20% down payment
A $400,000 home with a 20% down payment goal needs $80,000 - with $10,000 saved and $1,200/month set aside, that's about 58 more months.
Lower down payment
The same home with a 10% down payment goal ($40,000) roughly halves the time needed to reach the goal, though a smaller down payment usually means PMI on the eventual mortgage.
Advantages
- Turns an abstract savings goal into a concrete month count
- Easy to compare different down payment percentages side by side
- Shows exactly how increasing monthly savings shortens the timeline
- Useful for setting a realistic home-shopping start date
Common Mistakes
- Only saving for the down payment and forgetting closing costs, which typically add 2-5% more
- Assuming 20% down is required - many loan programs allow much less, with PMI as the trade-off
- Not accounting for how home prices might rise while you're still saving
- Keeping down payment savings in a low-yield account when a high-yield savings account could help it grow faster
Edge Cases to Watch For
- This doesn't account for home prices potentially rising while you save, which would raise the actual dollar target partway through your timeline.
- Closing costs (typically 2-5% of the purchase price) are a separate expense from the down payment and should be budgeted for on top of this goal.
- Down payment savings sitting in an interest-bearing account would reach the goal slightly faster than this simple linear projection accounts for.
- Many loan programs allow down payments well below 20% (sometimes as low as 3%), so a 20% target is a choice, not a universal requirement.
Common Use Cases
- Setting a savings goal and timeline for a future home purchase
- Comparing how different down payment percentages affect your timeline
- Deciding how much to increase monthly savings to hit a target date sooner
- Planning around a specific home price range