About honestcalculator

Who runs this

This site is built and maintained by Teodor-Cristian Lutoiu — a software engineer based in Bucharest, Romania. I build the calculators, write the explanations, verify the math, and sign my name to every page.

You can reach me at contact@teodorlutoiu.com, and you can see my other work at teodorlutoiu.com.

I'm not a licensed financial advisor, tax preparer, or attorney. What you see on this site is math — deliberate, transparent, checked — not personalized advice. For decisions that carry real financial consequence, talk to a qualified professional.

What this site is

honestcalculator is a collection of US finance calculators. Each calculator does one thing well: takes your inputs, runs the formula, shows you the result, and shows you the formula so you can see how the number was produced.

Every page includes:

• An interactive calculator you can use immediately — no email required
• The formula in plain language, and in math
• At least one fully worked example with real numbers
• An FAQ covering the questions people actually ask about that calculation
• A last-updated date so you know the data and rules are current

That's the whole product. There is no premium tier, no coaching upsell, no "download our free guide" pop-up. A few tasteful ads pay the hosting bill.

Why "honest"?

If you've searched for "mortgage refinance calculator" lately, you already know why. The top results are dominated by big finance sites that lock the formula behind a sign-up wall, bury the actual math under three screens of affiliate links, and estimate your savings using assumptions they don't show you.

I wanted a calculator site that respects your time: enter numbers, get the answer, see the formula, move on. If that's useful, the site has done its job. If a calculation looks off to you, email me and I'll fix it.

How I pick what to calculate

The calculators here target US financial questions that are easy to get wrong and easy to verify. If a calculation can be done with a clean formula and public data, it belongs here. If it requires personal judgment, professional advice, or your own situational context — it doesn't.

New calculators get added when I find a common question that isn't well served by existing tools.

How the math is checked

Every calculator's formula is implemented as a pure TypeScript function with inline unit tests. The unit tests verify the output against hand-computed reference cases before the calculator ships. If you spot an error, email me with the inputs you used and the result you got — I'll verify and fix.