About

About Calculy

Last updated: 1 May 2025

Calculy exists because accurate financial, health, and math calculations should be free, fast, and accessible to everyone — not locked behind a subscription or buried in spreadsheets.

We built Calculy because we were frustrated with the existing options. Most free calculator sites are cluttered with ads, use outdated formulas, don't work on mobile, or require you to create an account before you can see your results. We set out to build the calculator site we actually wanted to use.

50,000+
Monthly users
20+
Free calculators
4.9★
Average rating
2024
Founded

Our mission

To make professional-grade financial, health, and mathematical calculations available to every person — free, instantly, and without barriers. Whether you're calculating your mortgage repayments, checking your BMI before a doctor's appointment, or working out the compound interest on your savings, you deserve accurate answers without jumping through hoops.

What we build

Calculy.io is a suite of free online calculators covering three domains:

Our commitment to accuracy

Every calculator on Calculy uses established, peer-reviewed formulas:

  • Mortgage and loan calculators use the standard amortisation formula: M = P × r(1+r)^n / ((1+r)^n − 1)
  • Compound interest uses A = P(1 + r/n)^(nt) per standard financial mathematics
  • BMI follows WHO classification standards (18.5–24.9 normal range)
  • Calorie calculator uses the Mifflin-St Jeor equation, validated as the most accurate for the general population by peer-reviewed nutrition research
  • Body fat uses the US Navy method, validated against DEXA scanning
  • Pregnancy due date uses Naegele's rule plus IVF-specific adjustments
  • Stamp duty rates are sourced directly from each Australian state revenue office and updated annually

If you find an error in any of our formulas, please contact us immediately. We take formula accuracy seriously and will correct any errors within 24 hours.

Our values

🎯
Accuracy first
Every formula is sourced from official financial, health, and scientific standards. We cite our sources and update calculators when standards change.
🔓
Always free
Calculy will always have a free tier. We believe access to accurate financial and health calculations should not depend on your ability to pay.
🔒
Privacy by design
All calculations run in your browser. We don't store your financial data on our servers. What you calculate stays with you.
♿
Accessible to everyone
We build to WCAG 2.1 AA accessibility standards. Our calculators work on screen readers, keyboard navigation, and all device sizes.
⚡
No friction
No sign-up. No downloads. No paywalls on the core tools. Open the calculator, enter your numbers, get your answer.
🇦🇺
Australia-focused
While our tools work globally, we build with Australian users in mind — stamp duty by state, superannuation, GST, and the Australian tax system.

How we make money

Calculy is free to use and always will be. We generate revenue through:

  • Google AdSense — we display contextually relevant advertisements. These are clearly labelled as ads and are never intrusive to the core calculator experience.
  • Affiliate partnerships — where relevant, we may include links to financial products or services. These are always disclosed and never influence our calculator results or editorial content.

We are committed to never letting our revenue model compromise the accuracy, objectivity, or accessibility of our calculators. Ads are placed in designated slots and never interrupt the calculation workflow.

Disclaimers

Calculy provides calculations for informational and educational purposes only. Our calculators are not a substitute for professional financial, medical, or legal advice. Before making major financial or health decisions, please consult a qualified professional.

See our full Disclaimer for more detail, and our Privacy Policy for information on how we handle your data.

Contact us

We read every message. If you have a question, find an error, want to suggest a new calculator, or are interested in advertising or partnerships, please reach out: