CalcLumen: Everyday Calculators
124 free calculators and converters for mortgages, interest, home projects, health and dates. No signup, and every tool comes with a plain-English explainer and FAQ.
What it is
CalcLumen is a collection of online calculators and converters. The home page currently counts 124 of them, sorted into Finance, Auto, Business, Health, Date & Time, Math, Conversions and Home & DIY. Each calculator has its own page: the live tool at the top with a worked example already filled in, then a short how-to, the formula, and an FAQ. There's also a Guides section with explainers such as how to calculate standard deviation or why a terabyte is sometimes 1,000 GB and sometimes 1,024.
This is one of our own projects. The site is English only, and the money tools lean American: 401(k), Roth IRA, HSA, federal tax by filing status.
Why we picked it
The calculators are the point here, not an excuse for a long article. Open the mortgage payment calculator and you immediately get the monthly payment split into principal and interest, property tax, insurance, PMI and HOA, plus a loan-balance chart and a year-by-year amortization schedule. You can switch currency, copy the result or a link to it, and print or save the page as a PDF. There's a save-to-favorites button and a dark theme.
We also like that the math isn't hidden. Under the result you'll find the actual formula and a plain note that it's an estimate, not financial advice. Some calculators, including mortgage and compound interest, come with a copy-paste embed snippet for your own site.
Where to start
- Open the mortgage calculator and change the down payment to see how total interest moves.
- Try compound interest with a monthly contribution and compare what you put in against what interest adds.
- Browse Home & DIY for paint, tile, concrete and drywall estimates before a store run.
- Use the Math section for percentages, fractions, number-to-words and Roman numerals.
- Read a guide when you want the reasoning, not just the number.
Who it's for
Anyone who needs a quick, specific answer without installing an app or creating an account. It's especially handy for US-style money questions like PMI, retirement accounts and sales tax, and for everyday unit and date math.
Quick answers
Do I need an account? No. Every calculator opens straight away and is free.
Can I embed a calculator on my site? Yes, a subset of calculators offers an embed code with a required credit link.
Is the advice personalized? No. Results are estimates for general information, as each page states.
