GetCalcMaster

Mortgage calculator (educational)

Amortization, extra payments, PMI, escrow, and adjustable‑rate scenarios — with export and notebook handoff.

Important: Educational estimates only. Real mortgages include lender-specific fees, compounding conventions, escrow rules, PMI policies, rounding, and legal terms. Always verify with your lender and official documents.
Inputs
Start simple, then expand advanced options.
Model: amortization
HOME PRICE
DOWN PAYMENT
LOAN TERM
INTEREST RATE (note rate)
Percent per year (nominal). APR can differ once fees/points are included.
START DATE
Used for schedule dates (optional).
PAYMENT FREQUENCY
Biweekly/weekly can reduce total interest.
Escrow, PMI, and extra payments
ESCROW (optional)
PROPERTY TAX (annual)
INSURANCE (annual)
HOA (monthly)
PMI (optional)
PMI rate (annual %)
Cancel at LTV
EXTRA PAYMENTS (optional)
Extra per payment
One‑time lump sum
Lump sum month #
Extra payments reduce principal first (typical), which can shorten payoff and reduce interest.
Adjustable‑rate mortgage (ARM) schedule (optional)
Add rate changes by payment # (1 = first payment). The payment is re‑amortized at each change using the remaining balance and remaining term.
ARM enabled
SCHEDULE
Format: payment#:rate per line (e.g., 61:7.25).
Fees & APR estimate (optional)
Enter points/fees to estimate an effective APR (simplified). We treat fees as prepaid finance charges (paid upfront). Regulatory APR calculations can differ by lender and jurisdiction.
POINTS (% of loan)
1 point = 1% of loan amount.
LENDER FEES (amount)
Origination, underwriting, etc. (simplified).
Results
Payment + totals + payoff date. Schedule below.
PAYMENT (P+I)
—
TOTAL PAYMENT
—
TOTAL INTEREST
—
PAYOFF
—
HOUSING COST (with escrow/PMI)
APR / CASH TO CLOSE (optional)
NOTES
Amortization schedule
Switch between monthly and annual views to keep it readable.
Period Pay Prin Int Extra Bal
Tip: swipe sideways to see all columns.

How this mortgage calculator works

GetCalcMaster simulates an amortization schedule (payment-by-payment) based on your loan amount, rate, term, and payment frequency. Advanced options let you explore extra payments, PMI/escrow estimates, and adjustable‑rate (ARM) scenarios.

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Note: Education only. Outputs are estimates and may not match your lender. Fees, rounding, compounding conventions, escrow rules, PMI policies, and legal terms vary. Always verify with your lender and official documents.
Quick steps
  1. Enter loan basics: home price (or loan amount), down payment, interest rate, and term.
  2. Optionally expand advanced inputs (extra payments, PMI/escrow, ARM scenarios, and fees).
  3. Review monthly payment, payoff timeline, total interest, and the amortization schedule.
  4. Export your scenario for record‑keeping, then verify details with lender disclosures and official documents.
  • Each period, interest is computed on the remaining balance; the payment is split into interest and principal.
  • Extra payments apply to principal (when enabled) and can reduce total interest and shorten payoff time.
  • PMI and escrow are optional estimates for learning; lenders use specific policies and local requirements.
  • ARM scenarios model scheduled rate changes as a what‑if plan; actual rates depend on your index, margin, caps, and contract terms.
  • CSV export and notebook handoff are designed for scenario comparison and learning.
Amortization math (high level)

For a fixed-rate loan, the periodic payment is determined by the standard amortization relationship between principal, periodic interest rate, and number of payments.

Each payment reduces the balance. Early payments are interest-heavy; later payments are principal-heavy.

  • Interest this period ≈ balance × periodic rate.
  • Principal this period = payment − interest (minus any modeled fees/escrow if applicable).
  • New balance = old balance − principal − extra principal.
Extra payments and payoff insights

Extra payments are modeled as additional principal. This typically reduces the remaining term and total interest paid.

Small recurring extras can have a large impact early in the loan — but confirm your lender’s rules for applying extra principal.

PMI, escrow, and fees
  • PMI is usually tied to loan-to-value (LTV) thresholds and lender rules; this tool provides a simplified estimate.
  • Escrow (tax/insurance) varies by location and lender; treat it as a planning input, not a quote.
  • APR calculations are legally defined and lender-reported APR can differ from simplified estimates.
Rounding and conventions
  • Lenders may compound and round differently. Minor differences are normal.
  • Some schedules treat payment dates and day-count conventions (30/360 vs actual/365) differently.
  • Use this as a learning model; verify final numbers with official loan documents.
Privacy

Calculations run locally in your browser. Loan inputs are not sent to the server.

If you enable “Remember inputs”, values are stored only in local browser storage on this device.

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Cookies & privacy

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