Finance Calculators
Every money decision is a calculation wearing a disguise. This hub collects CalcSmith's borrowing, housing, debt and saving tools — each with instant results, the formula it uses, and a worked example you can verify.
Borrowing & loans
Auto Loan Calculator
Monthly payment, total interest and amortization for any car loan.
🎓Student Loan Calculator
Monthly payment, total interest and payoff date for student loans — plus the power of extra payments.
⚖️Loan Comparison Calculator
Compare up to three loan offers side by side on total cost, interest and payment.
🔑Home Equity Loan Calculator
Payment, total interest and combined loan-to-value for home equity loans.
Housing & mortgages
Car Insurance Cost Estimator
Estimate your annual and monthly car insurance premium from the factors insurers actually use.
🏠PMI Calculator
Monthly PMI cost, total PMI and the exact month it drops off your mortgage.
🏡Mortgage Calculator
Full monthly mortgage payment — principal, interest, tax, insurance and PMI — with amortization.
Debt, saving & investing
CD Calculator
Maturity value, interest earned and APY for certificates of deposit at any rate and term.
💳Credit Card Payoff Calculator
Months to debt-free and total interest for any card balance and payment.
📈Compound Interest Calculator
Final balance, contributions and growth for savings and investments over any horizon.
🌅Retirement Savings Calculator
Project your retirement balance with contributions, employer match and compound growth.
％Percentage Calculator
Percent of a number, percentage share and percentage change — instantly.
How to use these tools well
Calculators do not make decisions — they make decisions visible. The pattern that gets the most from this page is compare, don't just compute. Run the loan you were offered, then run the loan you wish you were offered: a point less of APR, two years shorter, 5% more down. The gap between those two results is your negotiating target, priced in dollars. Lenders negotiate against monthly payments because payments can be disguised by term length; totals cannot. That is why almost every tool here leads with a total — total interest, total cost, total growth.
Second: stress-test before you celebrate. Any plan that only works at the exact numbers you typed is fragile. Raise the interest rate a point, lower the investment return two points, add a year to the payoff. If the plan still works under worse assumptions, it is probably a good plan. If it collapses, the calculator just saved you from learning that the expensive way.
Third: respect the order of operations in personal finance, because the math enforces it. Expensive debt compounds against you faster than investments compound for you, so payoff tools usually come first; an employer retirement match is an instant 50–100% return, so it comes before almost everything; and insured, boring products like CDs are for money with a date attached, not for long-term growth. The hub is ordered the way the decisions usually arrive: borrow carefully, house carefully, kill bad debt, then let compounding do the heavy lifting.
Frequently asked questions
Which finance calculator do I need for a car purchase?
Start with the auto loan calculator for the payment and total interest, then the car insurance estimator for the other half of ownership cost. If the dealer and your bank both make offers, line them up in the loan comparison tool and choose by total cost.
Can these calculators replace financial advice?
No. They give you accurate arithmetic and a clearer view of trade-offs, which is most of what everyday money decisions need — but they cannot see your full situation, tax position or risk tolerance. For large, irreversible decisions, use the numbers here to have a much better conversation with a qualified advisor.
Why do your results differ slightly from my lender's?
Lenders may count days differently, round payments up, add fees we do not know about, or set the first payment date a month out — each shifts results by small amounts. The formulas are the same ones lenders use, so differences should be small; if a quote differs a lot, ask the lender which input is different. That question alone has saved borrowers thousands.