About HardCalc
Last updated: September 11, 2026
HardCalc publishes free loan calculators and text utilities. The calculators cover borrowing most people only do once or twice in a lifetime — a home equity line, an RV, a boat, a parcel of land, a motorcycle — where a single misunderstood term can cost tens of thousands of dollars.
Why this site exists
Most loan calculators return one number: the monthly payment. That is the number a seller wants you to focus on, and it hides everything that actually determines what the loan costs you. How much of your first payment is interest. What the total is over the full term. What happens when a balloon comes due, or when a HELOC draw period ends and the payment jumps.
Every calculator here shows the complete month-by-month amortization schedule, the total interest, and the specific trap that belongs to that loan type. You can export the whole schedule to CSV or print it. Nothing is held back behind an email form.
How the math works
Monthly payments use the standard amortization formula P = B × r / (1 − (1 + r)−n), where B is the amount financed, r is the annual rate divided by twelve, and n is the number of months. Each payment covers that month's interest first; the remainder reduces the balance.
Rather than using a closed-form shortcut, the calculators step through the loan one month at a time. That is what makes it possible to apply extra payments correctly, to stop a schedule at a balloon date, to switch a HELOC from interest-only to amortizing, and to adjust the final payment so the balance lands exactly at zero instead of a few cents off.
Where a calculator needs a convention, it follows U.S. market practice and says so on the page — for example, subtracting a trade-in before applying sales tax, or computing home equity borrowing power as (home value × maximum CLTV) − mortgage balance.
How the numbers are checked
Every calculator on this site ships with an automated test suite that runs before any change is published. The tests check each formula against independently calculated reference values, confirm that amortization schedules end at a zero balance, verify that extra payments and balloon dates behave correctly, and check that every figure published in the articles still matches what the calculator returns.
If a formula breaks, the tests fail and the change does not go out. This matters more here than on most sites: a calculator that is quietly wrong is worse than no calculator at all.
What HardCalc is not
- Not financial advice. The results are estimates for planning and comparison. Your actual terms come from a lender, based on your credit, income and the specific asset.
- Not a lender or broker. We do not originate loans, arrange financing, or take applications.
- Not a lead generator. There is no form, no sign-up, no email capture and no credit check. We do not collect or sell your information to lenders.
Privacy by design
Every tool runs entirely in your browser using JavaScript. The prices, balances, rates and text you enter are processed on your own device and are never transmitted to a server. This is not a policy promise we ask you to take on faith — it is how the tools are built. You can disconnect from the internet after a page loads and every calculator still works.
How the site is funded
HardCalc is supported by advertising, which is what keeps every tool free and free of sign-up walls. Advertising does not influence the content: the articles describe the risks of each loan type as plainly as the benefits, and no lender pays for placement or for favourable treatment in what we publish.
Corrections and contact
If you find a figure that looks wrong, or a calculator that behaves oddly, please tell us — corrections are made quickly and the tests are extended so the same mistake cannot return. Reach us through the contact page.