Down Payment Savings Calculator
Project a future home price and down payment target, then estimate monthly savings using current savings and growth assumptions.
Home & Housing · Last reviewed: August 10, 2026
On this page
Overview
The Down Payment Savings Calculator projects an entered home price to a planned purchase year, applies a target down payment percentage, and estimates the level monthly savings needed after current savings.
This is a deterministic cash-savings illustration. It does not model investment earnings on current or future savings.
Scope and Use
Use the result to explore how a purchase horizon, home-price estimate, down payment target, existing savings, and planning growth assumption affect a simple monthly savings target. Home price growth is an overridable governed planning assumption, not a forecast.
Outside this model
- Mortgage qualification, affordability, debt-to-income analysis, or loan approval.
- Closing costs, points, PMI, taxes, insurance, maintenance, moving costs, or transaction fees.
- Investment returns or interest on savings, taxes on earnings, account restrictions, or market risk.
- Changing home-price growth, regional or property-specific pricing, and purchase dates other than whole years.
- Mortgage, real-estate, investment, tax, legal, or financial advice.
Inputs and Outputs
Labels and ordering follow the active Down Payment Savings configuration. The home-price-growth assumption is advisor overridable, while dollar outputs are rounded to whole dollars.
| Field | Format | Meaning | Interpretation |
|---|---|---|---|
| Home Priceinput | Currency | User-entered estimate of the home's purchase price in today's dollars. | This is not an appraisal, listing price, or affordability limit. |
| Years Until Purchaseinput | Number | Whole years until the planned purchase date. | The model converts this horizon to twelve equal savings months per year. |
| Down Payment Percentageinput | Percentage | Target down payment as a percentage of the projected future home price. | The percentage does not determine mortgage eligibility or PMI treatment. |
| Current Savingsinput | Currency | Cash already designated for the down payment. | Current savings are subtracted directly and do not earn modeled interest or investment return. |
| Required Monthly Savingsoutput | Currency | Level monthly amount needed to close the remaining savings gap by the purchase date. | This is a linear division with no earnings; an already funded target returns zero. |
| Remaining Savings Gapoutput | Currency | Projected down payment target minus current savings, floored at zero. | A zero gap does not indicate mortgage qualification or cover excluded purchase costs. |
| Projected Down Payment Targetoutput | Currency | Target down payment percentage applied to the projected future home price. | This is the modeled down payment target before subtracting current savings. |
| Projected Home Priceoutput | Currency | Entered home price compounded to the planned purchase date. | The constant growth assumption is a planning input, not a forecast. |
- Field
- Home Priceinput
- Format
- Currency
- Meaning
- User-entered estimate of the home's purchase price in today's dollars.
- Interpretation
- This is not an appraisal, listing price, or affordability limit.
- Field
- Years Until Purchaseinput
- Format
- Number
- Meaning
- Whole years until the planned purchase date.
- Interpretation
- The model converts this horizon to twelve equal savings months per year.
- Field
- Down Payment Percentageinput
- Format
- Percentage
- Meaning
- Target down payment as a percentage of the projected future home price.
- Interpretation
- The percentage does not determine mortgage eligibility or PMI treatment.
- Field
- Current Savingsinput
- Format
- Currency
- Meaning
- Cash already designated for the down payment.
- Interpretation
- Current savings are subtracted directly and do not earn modeled interest or investment return.
- Field
- Required Monthly Savingsoutput
- Format
- Currency
- Meaning
- Level monthly amount needed to close the remaining savings gap by the purchase date.
- Interpretation
- This is a linear division with no earnings; an already funded target returns zero.
- Field
- Remaining Savings Gapoutput
- Format
- Currency
- Meaning
- Projected down payment target minus current savings, floored at zero.
- Interpretation
- A zero gap does not indicate mortgage qualification or cover excluded purchase costs.
- Field
- Projected Down Payment Targetoutput
- Format
- Currency
- Meaning
- Target down payment percentage applied to the projected future home price.
- Interpretation
- This is the modeled down payment target before subtracting current savings.
- Field
- Projected Home Priceoutput
- Format
- Currency
- Meaning
- Entered home price compounded to the planned purchase date.
- Interpretation
- The constant growth assumption is a planning input, not a forecast.
Methodology
H0 is the entered home price, g is the effective annual home-price-growth assumption, and y is the whole-year horizon.
d is the entered down payment percentage expressed as a decimal.
S0 is current savings. The monthly target is a straight-line allocation and does not compound any savings balance.
The calculator retains full precision through the projection, target, gap, and monthly division, then rounds each final output to the nearest whole dollar.
Assumptions and Limitations
Model assumptions
- Home price grows at one constant annual rate through the purchase date.
- The target percentage applies to the projected future home price.
- Current savings remain available but earn no modeled return.
- The remaining gap is saved evenly over twelve months per year.
Limitations
- Actual home prices may differ by location, property, and market conditions.
- Actual savings progress may vary with timing, earnings, withdrawals, and irregular contributions.
- The national historical index used for the internal planning default does not predict a particular home's price.
- Whole-dollar outputs may not reconcile from rounded displayed intermediates.
Selected Sources
- All-Transactions House Price Index for the United States
U.S. Federal Housing Finance Agency via FRED · Retrieved June 28, 2026
The national historical house-price index used to derive the internal home-price-growth planning default. It does not support the calculator formula, forecast future appreciation, or estimate a user-specific property's value.
1975 Q1–2026 Q1 planning calculation; reviewed August 10, 2026