How We Calculate

How the VersusCalcs comparisons are built, where the facts come from and what the results can and cannot tell you.

Our approach

A calculator is only useful if you can see how it reached its answer. Each VersusCalcs page explains its method in plain language, names the formulas and published figures behind it and tells you which numbers are defaults you should replace. We use published formulas and public sources, we avoid hidden assumptions and we do not let advertising change a result.

How a comparison is built

Each page opens with a verdict, a one-line answer to which one fits which situation. Below it, a table sets the two side by side on the facts that matter, and a short section explains how to tell them apart or what to weigh. A calculator or quiz then applies your own numbers, such as your usage, your region or your priorities. The facts come from the sources linked on the page, and we say when a figure is approximate.

Animals

Animal comparisons focus on identification and on differences in size, features, range and behavior, drawn from reference works such as All About Birds, the Animal Diversity Web and the San Diego Zoo. Where a pair can look alike, the page says which features are the most reliable. Size and range figures are typical values, and individuals vary.

Home, kitchen and yard

Home and kitchen comparisons use manufacturer and government sources, such as ENERGY STAR and the U.S. Energy Information Administration for energy use, and the U.S. Forest Products Laboratory and the Wood Database for wood properties. Yard comparisons rely on university extension services, since plant performance depends on your region. Cost comparisons use average prices, which vary by market.

Auto

Vehicle comparisons use fueleconomy.gov and the U.S. Department of Energy’s Alternative Fuels Data Center for fuel economy and charging, with consumer-review sources for context. Actual costs depend on your driving, your local prices and the specific vehicle.

Time zones

Time-zone comparisons use the IANA time zone database, the standard reference behind most software, and time standards from NIST. Daylight saving rules change by country and year, so confirm the date and time for an important meeting or flight.

Calculators

The calculator on each page applies your own numbers to the facts in the comparison table using simple arithmetic and the defaults shown on the page, which you can change. Where a default is a typical value, the page says so.

Finders and quizzes

The finders ask a few questions and apply fixed rules to match you to a result. They are not scored by a model, and the result is a starting point for a choice, not a recommendation. Your answers travel in the result page’s address, which the privacy policy explains.

Limits

A comparison reduces a lot of detail to a verdict. Real choices depend on details only you know. Use the verdict to narrow the options, then check the specifics that matter to you with the linked sources or a professional.