Data Source and Methodology
All calculations are based on standard mortgage formulas and data from authoritative financial sources. Consult your financial advisor for personalized advice.
The Formula Explained
The monthly payment for an ARM is calculated using the formula:
PMT = [P * r * (1 + r)^n] / [(1 + r)^n - 1]
Glossary of Terms
- Loan Amount: The total amount borrowed.
- Interest Rate: The initial rate applied to the loan.
- Loan Term: The duration over which the loan is repaid.
Frequently Asked Questions (FAQ)
What is an ARM?
An ARM is a mortgage with an interest rate that may change periodically depending on changes in a corresponding financial index.
How often do ARM rates change?
ARM rates can change annually, but this depends on the terms of your loan.
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
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Variables and units
- T = property tax (annual or monthly depending on input) (currency)
- I = homeowners insurance (annual or monthly depending on input) (currency)
- PMI = private mortgage insurance (monthly) (currency)
Sources (authoritative):
- Home — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/ - Finance — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/finance - Mortgage & Real Estate — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/subcategories/finance-mortgage-real-estate - Mortgage Payment Calculator - Monthly Payment Estimator with Taxes & Insurance — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/mortgage-payment - Mortgage Points Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/mortgage-points - Refinance Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/refinance-calculator - Canadian Mortgage Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/canadian-mortgage - Private Mortgage Insurance (PMI) Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/pmi
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.