About calcgeeks

calcgeeks is an independent calculator site with one stubborn rule: never hand someone a number without showing where it came from.

Why this site exists

The internet is full of calculators that spit out an answer and move on. Type in your numbers, get a figure, and you're left to wonder — is that right? What formula did it use? Does it apply to my situation? For something as consequential as a loan payment, a savings projection, or a health screening number, "just trust me" isn't good enough.

calcgeeks started from a simple frustration with that. I wanted a place where the calculator is only half the page. The other half explains the math: the equation in plain symbols, a worked example you can follow line by line, the assumptions baked in, and the situations where the tool will quietly mislead you if you're not careful. The result is a site you can use to get an answer and to actually understand it.

Who's behind it

Hi, I'm Analena Shull 👋

I spent about 15 years working in finance, and the same two struggles came up again and again: people who couldn't get a handle on budgeting their income, and people who had no idea how the numbers behind their loans actually worked — how a payment gets split between interest and principal, or why a loan ends up costing what it does.

I built calcgeeks to fix that. After years of explaining these things one client at a time, I wanted a place that does it for everyone, for free — calculators that show their work, and plain-English guides that help you make smarter decisions about purchases, loans, and everyday expenses. The goal is simple: to help you feel genuinely confident with your money and your choices, instead of just hoping the numbers work out.

calcgeeks is independent. It's not a bank, a lender, an insurer, or a medical provider, and it doesn't sell any of those products. That independence is the point — the calculators have no incentive to nudge you toward a particular loan, account, or outcome. The site is funded by unobtrusive display advertising, which keeps every tool and guide free to use.

Have a correction, a question, or a calculator you'd like to see? I genuinely want to hear it — the contact page reaches a real person (me).

How we build and check our calculators

Every tool on calcgeeks follows the same process:

• Start from a published formula. I use the standard, verifiable equations — amortization formulas for loans, the WHO body-mass-index definition for BMI, Naegele's rule for due dates, and so on. I don't invent math.
• Show the formula on the page. If I can't explain the calculation clearly, I don't publish the tool.
• Test against known answers. Each calculator is checked against worked examples from textbooks and official sources, and re-checked whenever the code changes.
• Mark the boundaries. Where a result could be mistaken for professional advice, I say plainly what it is and isn't, and point you to the right kind of expert.

Editorial independence

I run advertising to keep the site free, but ads never influence how a calculator works or what it tells you. The math is the math. If an advertiser's product would produce a worse result for you, the calculator will still say so. I'd rather lose a click than lose your trust.