What Unit Calc Hub provides
Unit Calc Hub offers free browser-based tools for dates, age, percentages, measurements, shape area, rectangular land area and adult BMI. Each calculator page includes an explanation, example and relevant limitations so you can check whether its result fits your question. No account is needed.
Calculation conventions
Date differences count calendar days, including weekends and holidays. Age uses completed calendar anniversaries and clamps a February 29 birthday to February 28 in non-leap years. Unit conversions use the factors described on the individual pages. Volume options are US liquid measures; a ton is a US short ton. Shape and land calculations use the dimensions you enter rather than surveying or assessing a property.
Precision and checking a result
Displayed values may be rounded. Conversion input fields retain up to 12 significant digits, so a converted value may not round-trip exactly. The precision of the original measurement still controls how meaningful the result is. Check the page’s worked example, verify your units and compare important results with an authoritative source.
Reference material
Our explanations are written for these tools and distinguish calculator assumptions from real-world measurements. Useful external references include NIST’s SI length guidance and CDC’s adult BMI guidance. External organizations do not endorse this website.
Corrections and contact
To report an incorrect result or a site problem, email [email protected]. Include the tool’s URL, non-sensitive sample inputs, selected units and the result you expected. We can then reproduce the calculation. Avoid sending personal health information or other sensitive data.
Privacy and advertising
Calculator logic runs in your browser. Advertising and hosting services have separate data practices described in our Privacy Policy. Advertising helps support access to the tools. Read the Terms of Use for the conditions of use.