TetraKits
Calculate monthly loan payments, total interest paid, and a full amortization schedule. Enter loan amount, annual interest rate, and term in years — see payment breakdown and how principal vs interest shifts over time. The TetraKits Loan Calculator runs entirely in your browser — free, private, and ready on mobile or desktop.
Overview
Auto loans, personal loans, and equipment financing all use the same amortization math — but lenders quote different rates and terms. Model monthly payments and total interest cost before committing to a loan.
How to use the loan calculator
- Enter loan details — Type principal (loan amount), annual interest rate, and term in years. Example: $20,000 at 6% for 5 years.
- Read monthly payment — See fixed monthly payment using standard amortization: M = P[r(1+r)^n]/[(1+r)^n−1].
- Review amortization — Check total interest and payment schedule. For home loans, use the mortgage calculator.
Common use cases
- Enter loan details: Type principal (loan amount), annual interest rate, and term in years.
- Read monthly payment: See fixed monthly payment using standard amortization: M = P[r(1+r)^n]/[(1+r)^n−1].
- Review amortization: Check total interest and payment schedule.
- Bookmark for quick access: Save the tool for repeat tasks without installing an app.
Frequently asked questions
How is the monthly payment calculated?
Standard amortization formula: M = P × [r(1+r)^n] / [(1+r)^n − 1], where P = principal, r = monthly rate, n = total months.
Does this include taxes or insurance?
No. This calculates principal and interest only. Mortgages often add escrow for taxes and insurance separately.
Can I see how much goes to interest vs principal?
Yes. The amortization schedule shows each payment split between principal reduction and interest cost.
What is the difference between this and the mortgage calculator?
This handles general loans. The mortgage calculator adds down payment, PMI, and home-specific fields.
Is this loan calculator free?
Yes. Unlimited calculations with no signup.
