About CalcLumen

CalcLumen is a free collection of 48 calculators and converters for money, health, dates, math and everyday conversions — no signup, no clutter, just a clear answer the moment you type.

What we do

Every tool lives on its own page and does one job well — from a mortgage payment or compound-interest projection to BMI, a due date, or a unit conversion. Each page explains the formula in plain English and answers the questions people actually ask, so you understand the result and not just the number.

How we keep it accurate

Our calculators use established, published formulas — standard loan amortization, the Mifflin-St Jeor equation for calories, the US Navy method for body fat, Naegele’s rule for due dates, and so on. We show the method on each page so you can check the math yourself. When a tool relies on a reference table (tax rates, unit factors, indicative currency rates), we label it clearly and note when it was last updated.

That said, results are estimates for general information only and are not professional financial, medical, tax or legal advice. For decisions that matter, please check with a qualified professional.

Privacy first

CalcLumenruns entirely in your browser — you don’t need an account, and your inputs never leave your device. Favorites and preferences are stored locally on your device, not on our servers. See our privacy policy for the details.

Get in touch

Spotted a mistake, or want a calculator we don’t have yet? We read every message — head to our contact page.