Down Payment Calculator

Down Payment is evaluated from Home Purchase Price, Down Payment and Mortgage Interest Rate. The calculation reports Down Payment Amount, Loan Amount and Monthly Payment.

Results

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About the Down Payment Calculator

Down Payment is treated here as a quantitative relation between Home Purchase Price, Down Payment, Mortgage Interest Rate and Loan Term and Down Payment Amount, Loan Amount, Monthly Payment and Est. Monthly PMI.

The calculator uses a multi formula configuration. Each reported value is read as a direct evaluation of the stored rules with the declared field formats and units.

Formula basis:
Down Payment Amount = Home Price x (Down Payment% / 100)
Loan Amount = Home Price - Down Payment Amount
Monthly Payment (P&I) = Loan x r x (1+r)ⁿ / [(1+r)ⁿ - 1]
Where r = mortgage rate / 1200, n = loan term months
PMI (if down payment < 20%):
Estimated Monthly PMI = Loan Amount x 0.0085 / 12
(0.85% annual PMI rate; actual rates vary by lender and LTV)

Interpret the outputs in the order shown by the result fields. Optional inputs affect only the outputs that depend on those variables.

Formula & How It Works

The calculation applies the following relations exactly as recorded in the metadata:

Down Payment Amount = Home Price x (Down Payment% / 100)
Loan Amount = Home Price - Down Payment Amount
Monthly Payment (P&I) = Loan x r x (1+r)ⁿ / [(1+r)ⁿ - 1]
Where r = mortgage rate / 1200, n = loan term months
PMI (if down payment < 20%):
Estimated Monthly PMI = Loan Amount x 0.0085 / 12
(0.85% annual PMI rate; actual rates vary by lender and LTV)

Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.

Worked Examples

Example 1: Standard 20% Down — No PMI

Inputs

home_price: 400000 down_payment_percent: 20 annual_rate: 6.75 loan_term_years: 30
Down Payment Amount: $80,000. Loan Amount: $320,000. Monthly Payment: $2,075.51. Est. Monthly PMI: $0

With Home Purchase Price = 400,000, Down Payment = 20, Mortgage Interest Rate = 6.75 and Loan Term = 30 as the stated inputs, the result is Down Payment Amount = $80,000, Loan Amount = $320,000 and Monthly Payment = $2,075.51. Each value corresponds to the declared output fields.

Example 2: First-Time Buyer — 5% Down with PMI

Inputs

home_price: 350000 down_payment_percent: 5 annual_rate: 7 loan_term_years: 30
Down Payment Amount: $17,500. Loan Amount: $332,500. Monthly Payment: $2,212.13. Est. Monthly PMI: $235.52

With Home Purchase Price = 350,000, Down Payment = 5, Mortgage Interest Rate = 7 and Loan Term = 30 as the stated inputs, the result is Down Payment Amount = $17,500, Loan Amount = $332,500 and Monthly Payment = $2,212.13. Each value corresponds to the declared output fields.

Example 3: 3.5% FHA Down Payment

Inputs

home_price: 280000 down_payment_percent: 3.5 annual_rate: 6.5 loan_term_years: 30
Down Payment Amount: $9,800. Loan Amount: $270,200. Monthly Payment: $1,707.85. Est. Monthly PMI: $191.39

With Home Purchase Price = 280,000, Down Payment = 3.5, Mortgage Interest Rate = 6.5 and Loan Term = 30 as the stated inputs, the result is Down Payment Amount = $9,800, Loan Amount = $270,200 and Monthly Payment = $1,707.85. Each value corresponds to the declared output fields.

Example 4: Large Down Payment — 35% Down

Inputs

home_price: 600000 down_payment_percent: 35 annual_rate: 6.75 loan_term_years: 15
Down Payment Amount: $210,000. Loan Amount: $390,000. Monthly Payment: $3,451.15. Est. Monthly PMI: $0

With Home Purchase Price = 600,000, Down Payment = 35, Mortgage Interest Rate = 6.75 and Loan Term = 15 as the stated inputs, the result is Down Payment Amount = $210,000, Loan Amount = $390,000 and Monthly Payment = $3,451.15. Each value corresponds to the declared output fields.

Common Use Cases

  • Calculate exact down payment needed for a target home price
  • See how down payment percentage affects monthly payment and PMI
  • Plan savings timeline to reach a down payment goal