Financial

Offline financial-format helpers like card-number validation and check-digit verification.

Credit Card Number Validator Tool

Validate a credit or debit card number locally using the Luhn check digit and common issuer prefix and length rules. This tool can help catch typos and identify likely card brands such as Visa, Mastercard, American Express, and Discover, but it does not contact any bank, charge anything, or confirm that a card is active or usable.

Financial

Residential Mortgage Amortization Schedule Calculator

Calculate a residential mortgage payment and full amortization schedule locally in your browser. Compare loan amounts, rates, terms, taxes, insurance, and extra principal payments without sending financial details anywhere.

Financial

Commercial Mortgage Amortization Schedule Calculator

Calculate a commercial mortgage payment and amortization schedule locally in your browser, including balloon terms and amortization periods. Model principal, rate, term, amortization, and extra payments without sharing financial data.

Financial