CalQpro

About CalQpro

CalQpro is a free, ad-supported reference site for math and life calculations — built around one principle: every calculator should show its formula, cite its source, and produce results you can verify by hand if you want to.

Why We Built This

Most calculator sites online have one of three problems: they bury the actual tool below five paywalls and pop-ups, they don't show their math (so you have no way to verify the result), or they're abandoned and reference outdated tax tables, BMI ranges, or interest rates. We started CalQpro because we kept hitting all three when trying to do simple things — figure out a refinance break-even, dose acetaminophen for a sick kid, calculate a mortgage with extra payments, or convert a recipe.

The thesis behind every page on this site: respect your time, show the work, and tell you exactly where the formula came from. No login walls, no email captures, no dark patterns. The site is funded entirely by display ads served against the calculator pages — so we can keep everything free and accessible to anyone with an internet connection.

What We Cover

CalQpro hosts over 220 calculators across 17 categories — finance, health, math, fitness, construction, statistics, physics, and a deep specialty section for live event production (lighting, audio, video, rigging). Categories are chosen based on three filters: real search demand, underserved by existing options, and answerable by a calculator (not a chatbot or a spreadsheet).

Examples of calculators we built because nothing online did them well:

Editorial Standards

Every calculator is built to a checklist before launch:

  1. Formula sourcing. Pulled from a primary authority — government code (NEC, IRS, CDC), peer-reviewed scientific reference (NIH, AHA), recognized professional standard (ANSI, AVIXA, IEEE), or in-domain industry consensus (CFPB, AAP, AVIXA). The source label and link are displayed next to every formula on every calculator. Every formula on the site is also collected in one place at our complete formulas reference.
  2. Pure-function implementation. All math runs in your browser as pure JavaScript functions with zero server dependencies. No data leaves your device. You could disconnect the internet after the page loads and the calculator would still work.
  3. Automated testing. Each calculator's math has unit tests cross-checking results against at least two independent reference tools (e.g. Bankrate, CFPB's mortgage calculator, manufacturer spec sheets). Tests run automatically on every code change. We currently maintain 210+ passing tests across the calculator library.
  4. Step-by-step explanations. Math-heavy calculators include collapsible "For Students" sections that walk through the actual computation using your inputs — not generic examples. The point is that you can verify the result by hand if you choose to.
  5. Disclosed limitations. Calculators that involve safety-critical decisions (electrical loads, structural rigging, medication doses, financial choices) display visible disclaimers explaining when professional consultation is required.

Who Builds and Reviews CalQpro

Jorge Sanchez

Jorge Sanchez

Live Event Production Specialist

Jorge is a live event production specialist based in Miami. He works hands-on with lighting, power distribution, rigging, and show-network setup for festivals and live events, with credentialed access at major sporting events. He builds CalQpro to put the calculation tools production crews use behind the scenes into the hands of anyone planning an event, balancing a budget, or making sense of the math behind everyday life.

contact@calqpro.comLinkedIn ↗

Specialty knowledge for the live event production calculators (lighting power, audio, video, and rigging) comes from hands-on work at festivals and live events — running lighting, distributing power, and rigging trusses on real shows. The math in those calculators is grounded in NEC 2023, ANSI E1.2-2012, IEC 61938, the Art-Net 4 specification, and Sabine's 1900 acoustic equation — but the design choices and defaults are informed by what actually happens on a load-in.

Privacy & Data Practices

We don't collect personal data. Calculator inputs are processed entirely in your browser and never sent to our servers. Site analytics use Google Analytics 4 with IP anonymization. Display ads are served by Google AdSense — they may use cookies for ad personalization, which you can opt out of via Google Ad Settings. Full details are in our privacy policy and cookie policy.

How We're Funded

CalQpro is supported entirely by display advertising. We do not sell user data, accept paid placements within calculator content, or run sponsored calculators. Ad slots are clearly marked "Advertisement" per FTC and IAB guidelines, and ad revenue has zero influence on which calculators we build, what formulas we use, or which sources we cite. If a calculator's recommendation conflicts with an advertiser's interest (e.g. our mortgage payoff calculator showing that paying down debt can beat investing), we ship the calculator anyway. The math is the math.

Found an Error? Want a Calculator We Don't Have?

Every calculator page has a "Report an error" link that opens a pre-filled email. Include the inputs you used, the result you got, and the result you expected with a source link. We respond within 2 business days and ship corrections within a week.

Calculator requests welcome too — if there's something you keep Googling and the existing options are bad, email us at contact@calqpro.com. The full Live Event Production category exists because someone asked for it.

Contact

General inquiries, bug reports, partnership questions, or press: contact@calqpro.com.

For security vulnerability reports, see our security.txt — we follow RFC 9116 disclosure practices.