Disclaimer

Last updated October 13, 2026

General

FastCalcs provides free calculators for general information and education. Every calculation is exact for the numbers you enter, using the formulas and assumptions explained on each page. What can differ is the real world: the rate a lender actually offers, the brand of paint you buy, or how your own body responds. So treat each result as a reliable guide, not a guarantee of what will happen.

We test every formula against hand-worked answers and published figures, as described in how we check our formulas. Even so, we can’t guarantee that every result is complete, correct or suitable for your situation. You use the results at your own risk, and you should check anything important with a qualified professional.

Financial calculators

Our mortgage, loan and auto loan calculators are not financial, investment, tax, legal or credit advice, and they are not an offer of credit.

• FastCalcs is not a lender, broker, bank or financial adviser.
• Interest rates shown by default are examples, not current market rates or rates you will be offered.
• Results assume a fixed rate and regular monthly payments. They may not include every fee, insurance cost, tax or local rule.
• Your lender’s figures can differ by a few cents because of rounding, and by more because of fees or terms.
• Rules such as mortgage insurance and sales tax vary by country, state and lender. Where a calculator follows a specific rule, such as US PMI rules, the page says so.

Before you borrow, rely on the official documents from your lender, such as a loan estimate or credit agreement, and consider speaking to a licensed financial adviser.

Fitness and health calculators

Our BMI, calorie and body fat calculators are not medical, nutritional or health advice, and they cannot diagnose or treat any condition.

• They use published formulas designed for healthy adults. They may not suit children, older adults, pregnant or breastfeeding people, athletes, or people with medical conditions.
• BMI and body fat estimates are screening tools. They don’t measure your health directly.
• Calorie figures are averages. Your real needs can differ by 10% or more.
• Talk to a doctor or registered dietitian before changing your diet or exercise, especially if you have a medical condition or a history of disordered eating.

If you think you may have a medical emergency, contact your local emergency number straight away.

Home and DIY calculators

Our concrete, paint and flooring calculators estimate material quantities and costs. They are not engineering, architectural or construction advice.

• Product yields and coverage vary by brand, so always check the label or packaging.
• Follow your local building codes and the manufacturer’s instructions.
• For structural work, such as foundations, load-bearing slabs and retaining walls, consult a qualified engineer or contractor.
• Measure twice before ordering, especially special-order materials that can’t be returned.

Outside sources

We link to official sources so you can check our formulas. We don’t control those websites and aren’t responsible for their content.

Questions or corrections

If you think a result is wrong, email hello@fastcalcs.app with the calculator’s name and the numbers you entered. We check every report.