About DollarSums
DollarSums is an independent website that builds free calculators for everyday money decisions: buying a home, paying off debt, financing a car and saving for the future.
Why we built this site
Many financial calculators online are lead-generation forms in disguise. They ask for your email or phone number before showing a result, push you toward a particular lender, or hide the assumptions behind a single big number. We wanted the opposite: tools that answer your question immediately, show exactly how the answer was calculated, and leave the decision to you.
Who runs DollarSums
DollarSums is created and maintained by David, an independent publisher based in Spain. The site isn't owned by a bank, a lender or any other financial company, so it has nothing to sell you. Its only goal is to let you see the real numbers behind a mortgage, a loan or a credit card balance before you commit to one.
How we build our calculators
- Standard formulas. Our calculators use the same amortization and compound interest math that banks and lenders use, and every page explains the formula in plain English.
- Stated assumptions. Where a calculator has to simplify, for example by applying interest monthly or estimating a credit card minimum payment, we say so on the page.
- Tested results. We check each calculator against reference values worked out independently before publishing, and again after any change.
- Regular reviews. Each page shows when it was last reviewed. If a rule or common practice changes, we update the explanation.
Your privacy
Every calculation happens in your own browser. The numbers you enter are never sent to our servers, and we don't ask you to create an account. Read our privacy policy for details, including how advertising on the site works.
How DollarSums is funded
The site is free to use and is supported by advertising served by Google AdSense. Ads are clearly separated from our content. Advertisers have no influence over how our calculators work or what our articles say, and we don't sell financial products.
Not financial advice
Our calculators and articles are for general educational purposes. They can't account for every detail of your situation. For major decisions, check the official documents from your lender or provider and consider speaking with a qualified financial professional.
Get in touch
Found a bug, a confusing explanation or a calculator you'd like us to build? We'd love to hear from you on our contact page.