Is the extra payment included in the estimated monthly housing payment?

Yes. The first-month headline includes the actual loan payment, recurring housing costs, and extra principal applied in that month, capped at the remaining balance. Later months can differ; use the cash-flow schedule. Unused amounts after payoff are listed separately and are not counted as spending.

What happens when Mortgage calculator receives an invalid or extreme value?

The page rejects missing, ambiguous, out-of-range, or non-finite values and refuses to display a non-finite result.

Why can Mortgage calculator differ from another result?

Different unit conventions, endpoint policies, fee or rate assumptions, formula domains, and premature rounding can produce a different answer.

Can I use Mortgage calculator as professional advice?

No. It is an educational estimate, not financial, tax, investment, accounting, or lender advice.

How can I verify the Mortgage calculator result?

Recalculate the two evaluated examples without rounding intermediate values and compare the declared formula or convention with Consumer Financial Protection Bureau mortgage guidance.

Mortgage calculator

Mortgage cost and payoff planner

Compare repayment with extra principal by month and your own housing-cost growth assumptions.

Property priceDown paymentAnnual interest rate (%)Term (whole years)Annual property taxAnnual home insuranceMonthly HOAMonthly PMIOther monthly housing costsUpfront closing costsExtra monthly principalFirst payment month (YYYY-MM)

Annual cost growth

User-entered annual changes apply from payment months 13, 25, and so on, not each January. Zero keeps the cost unchanged; PMI is fixed.

Property-tax annual growth (%) · 0–100Insurance annual growth (%) · 0–100HOA annual growth (%) · 0–100Other-cost annual growth (%) · 0–100

Extra principal in specific months

Add up to 120 distinct months in YYYY-MM format within the contract term. Each amount must be greater than zero. Blank or duplicate rows are errors; remove unused rows. Payments are applied after the regular monthly payment.

0 / 120

Estimated result

First-month outlay1,678.74

Contract principal and interest1,678.74

First-month recurring costs0.00

Loan principal280,000.00

Loan interest324,346.93

Estimated interest saved0.00

Estimated payoff360 months

Final payment monthAug 2056

Down payment and upfront costs70,000.00

Estimated outlay through payoff674,346.93

Progress chart

Compare repayment with extra principal by month and your own housing-cost growth assumptions.

Remaining balanceInterest

Estimated result	Contract plan	Selected plan
Loan interest	324,346.93	324,346.93
Loan payment	604,346.93	604,346.93
Estimated payoff (months)	360.00	360.00

Mortgage cash-flow schedule

Monthly and yearly rows include loan payments and all five housing costs. Down payment and upfront costs are separate, counted once. Yearly rows are successive 12-payment periods.

Displayed amounts are rounded to two decimals. Calculations and CSV keep full precision; totals can differ from the sum of individually rounded cells.

Period	Loan payment	Principal	Interest	Total cash outlay	Remaining balance
Sep 2026 – Aug 2027	20,144.90	3,438.43	16,706.46	20,144.90	276,561.57
Sep 2027 – Aug 2028	20,144.90	3,650.51	16,494.39	20,144.90	272,911.06
Sep 2028 – Aug 2029	20,144.90	3,875.66	16,269.23	20,144.90	269,035.40
Sep 2029 – Aug 2030	20,144.90	4,114.71	16,030.19	20,144.90	264,920.69
Sep 2030 – Aug 2031	20,144.90	4,368.49	15,776.41	20,144.90	260,552.20
Sep 2031 – Aug 2032	20,144.90	4,637.93	15,506.97	20,144.90	255,914.27
Sep 2032 – Aug 2033	20,144.90	4,923.99	15,220.91	20,144.90	250,990.28
Sep 2033 – Aug 2034	20,144.90	5,227.69	14,917.21	20,144.90	245,762.59
Sep 2034 – Aug 2035	20,144.90	5,550.12	14,594.78	20,144.90	240,212.47
Sep 2035 – Aug 2036	20,144.90	5,892.44	14,252.46	20,144.90	234,320.03
Sep 2036 – Aug 2037	20,144.90	6,255.87	13,889.02	20,144.90	228,064.16
Sep 2037 – Aug 2038	20,144.90	6,641.72	13,503.18	20,144.90	221,422.43
Sep 2038 – Aug 2039	20,144.90	7,051.37	13,093.53	20,144.90	214,371.07
Sep 2039 – Aug 2040	20,144.90	7,486.28	12,658.62	20,144.90	206,884.78
Sep 2040 – Aug 2041	20,144.90	7,948.02	12,196.88	20,144.90	198,936.76
Sep 2041 – Aug 2042	20,144.90	8,438.24	11,706.66	20,144.90	190,498.53
Sep 2042 – Aug 2043	20,144.90	8,958.69	11,186.21	20,144.90	181,539.84
Sep 2043 – Aug 2044	20,144.90	9,511.24	10,633.66	20,144.90	172,028.60
Sep 2044 – Aug 2045	20,144.90	10,097.87	10,047.03	20,144.90	161,930.73
Sep 2045 – Aug 2046	20,144.90	10,720.69	9,424.21	20,144.90	151,210.04
Sep 2046 – Aug 2047	20,144.90	11,381.92	8,762.98	20,144.90	139,828.13
Sep 2047 – Aug 2048	20,144.90	12,083.93	8,060.97	20,144.90	127,744.20
Sep 2048 – Aug 2049	20,144.90	12,829.24	7,315.66	20,144.90	114,914.96
Sep 2049 – Aug 2050	20,144.90	13,620.52	6,524.38	20,144.90	101,294.44
Sep 2050 – Aug 2051	20,144.90	14,460.60	5,684.30	20,144.90	86,833.84
Sep 2051 – Aug 2052	20,144.90	15,352.50	4,792.40	20,144.90	71,481.35
Sep 2052 – Aug 2053	20,144.90	16,299.41	3,845.49	20,144.90	55,181.94
Sep 2053 – Aug 2054	20,144.90	17,304.72	2,840.18	20,144.90	37,877.22
Sep 2054 – Aug 2055	20,144.90	18,372.04	1,772.86	20,144.90	19,505.18
Sep 2055 – Aug 2056	20,144.90	19,505.18	639.71	20,144.90	0.00

Formula

Mortgage calculator evaluates the registered expression “P=x₁−x₂; i=x₃/1200; n=12x₄; M={P/n:i=0;P·i(1+i)^n/((1+i)^n−1):i≠0}; R=M+x₅/12+x₆/12+x₇+x₈+x₉+x₁₁; x₁=Original price; x₂=Down payment; x₃=Annual interest rate; x₄=Term in years; x₅=Tax; x₆=Insurance; x₇=Monthly HOA; x₈=Monthly PMI; x₉=Other monthly costs; x₁₀=Upfront costs; x₁₁=Extra payment” with the validated inputs. Full calculation precision is retained until the result is formatted for display.

P=x₁−x₂; i=x₃/1200; n=12x₄; M={P/n:i=0;P·i(1+i)^n/((1+i)^n−1):i≠0}; R=M+x₅/12+x₆/12+x₇+x₈+x₉+x₁₁; x₁=Original price; x₂=Down payment; x₃=Annual interest rate; x₄=Term in years; x₅=Tax; x₆=Insurance; x₇=Monthly HOA; x₈=Monthly PMI; x₉=Other monthly costs; x₁₀=Upfront costs; x₁₁=Extra payment

Consumer Financial Protection Bureau mortgage guidance

What this calculator answers

Estimate fixed-rate principal and interest plus entered tax, insurance, HOA, PMI, other housing costs, and optional extra principal. Extra payments are included in the planned monthly outlay and used to inspect payoff time and total interest.

Variables, defaults, and limits

Original price: Original price is a number input. The displayed starter value is 350,000; it is an example, not a hidden assumption.; Default: 350,000; Accepted values: Minimum: 0.01. Numeric entries must be finite and unambiguous.
Down payment: Down payment is a number input. The displayed starter value is 70,000; it is an example, not a hidden assumption.; Default: 70,000; Accepted values: Minimum: 0. Numeric entries must be finite and unambiguous.
Annual interest rate: Annual interest rate is a number input. The displayed starter value is 6; it is an example, not a hidden assumption.; Default: 6; Accepted values: Minimum: 0. Numeric entries must be finite and unambiguous.
Term in years: Term in years is a number input. The displayed starter value is 30; it is an example, not a hidden assumption.; Default: 30; Accepted values: Allowed range: 1 to 100. Numeric entries must be finite and unambiguous.
Tax: Tax is a number input. The displayed starter value is 0; it is an example, not a hidden assumption.; Default: 0; Accepted values: Minimum: 0. Numeric entries must be finite and unambiguous.
Insurance: Insurance is a number input. The displayed starter value is 0; it is an example, not a hidden assumption.; Default: 0; Accepted values: Minimum: 0. Numeric entries must be finite and unambiguous.
Monthly HOA: Monthly HOA is a number input. The displayed starter value is 0; it is an example, not a hidden assumption.; Default: 0; Accepted values: Minimum: 0. Numeric entries must be finite and unambiguous.
Monthly PMI: Monthly PMI is a number input. The displayed starter value is 0; it is an example, not a hidden assumption.; Default: 0; Accepted values: Minimum: 0. Numeric entries must be finite and unambiguous.
Other monthly costs: Other monthly costs is a number input. The displayed starter value is 0; it is an example, not a hidden assumption.; Default: 0; Accepted values: Minimum: 0. Numeric entries must be finite and unambiguous.
Upfront costs: Upfront costs is a number input. The displayed starter value is 0; it is an example, not a hidden assumption.; Default: 0; Accepted values: Minimum: 0. Numeric entries must be finite and unambiguous.
Extra payment: Extra payment is a number input. The displayed starter value is 0; it is an example, not a hidden assumption.; Default: 0; Accepted values: Minimum: 0. Numeric entries must be finite and unambiguous.

Formula and calculation rule

P=x₁−x₂; i=x₃/1200; n=12x₄; M={P/n:i=0;P·i(1+i)^n/((1+i)^n−1):i≠0}; R=M+x₅/12+x₆/12+x₇+x₈+x₉+x₁₁; x₁=Original price; x₂=Down payment; x₃=Annual interest rate; x₄=Term in years; x₅=Tax; x₆=Insurance; x₇=Monthly HOA; x₈=Monthly PMI; x₉=Other monthly costs; x₁₀=Upfront costs; x₁₁=Extra payment

Worked examples