Frequently Asked Questions

DiffMetric is a free online unit converter that helps you quickly and accurately convert between different units of measurement. We support over 100 units across 14 categories including length, weight, temperature, volume, speed, digital storage, and more. Our goal is to provide the fastest, most accurate, and easiest-to-use conversion tool on the web.

Yes, DiffMetric is 100% free to use. There are no hidden fees, premium features, or subscription plans. All conversions, tools, and features are available to everyone at no cost. We believe that access to accurate unit conversion tools should be free for everyone.

No, you don't need to create an account or sign up to use DiffMetric. Simply visit our website and start converting. We don't require any personal information, registration, or login to access our conversion tools.

Our conversions are highly accurate and based on internationally recognized standards. We use precise conversion factors from authoritative sources including the International Bureau of Weights and Measures (BIPM), National Institute of Standards and Technology (NIST), and ISO standards. For most conversions, we maintain precision up to 10 decimal places internally, then display results in a user-friendly format.

We source our conversion factors from authoritative international standards organizations including: the International Bureau of Weights and Measures (BIPM), the National Institute of Standards and Technology (NIST), the International Organization for Standardization (ISO), and established scientific references. All factors are regularly reviewed and updated to ensure accuracy.

Yes, DiffMetric uses the same conversion factors found in scientific and engineering references. However, for critical applications in scientific research, engineering, or medical contexts, we recommend verifying results with official standards documentation and considering significant figures appropriate to your measurement precision.

Converting units is simple: 1) Navigate to the conversion page you need (e.g., meters to feet), 2) Enter your value in the input field, 3) The result appears instantly as you type. You can also use our homepage Quick Convert tool to select any category and units, or use the search bar to find specific conversions.

Yes! Every conversion page includes a swap button (↕) that instantly reverses the conversion direction. For example, if you're on the "Meters to Feet" page, clicking swap will change it to "Feet to Meters" while keeping your entered value. You can also find a "Convert reverse" link on each page.

There are several ways to find conversions: 1) Use the search bar at the top of the page (e.g., "miles to km"), 2) Browse by category from the homepage or navigation menu, 3) Visit our All Units page to see every available unit, 4) Use the Quick Convert tool on the homepage to select any units.

Yes! Each conversion has its own unique URL that you can bookmark in your browser. For specific values, we also have dedicated pages (e.g., /length/100-meter-to-foot/) that you can bookmark for quick reference. Simply use your browser's bookmark feature on any conversion page.

Absolutely! DiffMetric is fully responsive and works perfectly on smartphones, tablets, and desktop computers. The interface automatically adapts to your screen size for the best experience. No app download is required – just visit our website in any modern browser.

Yes, each converter includes a "Copy" button that copies the result to your clipboard with one click. You can then paste it anywhere you need. The copy button copies just the numerical value for easy use in documents, spreadsheets, or other applications.

Click the "Reset" button on any converter to clear your input and return to the default value of 1. This is useful when you want to start a new conversion without manually deleting your previous entry.

The metric system (SI) is based on units of 10 and is used by most countries worldwide. It includes meters, grams, and liters. The imperial system, used primarily in the United States, includes feet, pounds, and gallons. The metric system is generally easier for calculations because of its decimal-based structure, while imperial units are often based on historical standards. DiffMetric makes converting between these systems effortless.

The US gallon (3.785 liters) and UK gallon (4.546 liters) evolved from different historical standards. The US gallon is based on the English wine gallon, while the UK gallon (also called Imperial gallon) was standardized in 1824 based on the volume of 10 pounds of water. This difference affects fuel economy ratings, recipes, and other measurements. Always check which gallon type is being referenced, and use DiffMetric to convert between them accurately.

These are three different temperature scales: Celsius (°C) is based on water's freezing point (0°C) and boiling point (100°C) at standard pressure, used worldwide for everyday temperatures. Fahrenheit (°F) sets water's freezing at 32°F and boiling at 212°F, primarily used in the United States. Kelvin (K) is the scientific scale starting at absolute zero (-273.15°C), where all molecular motion stops. The scales intersect at -40°, where Celsius and Fahrenheit are equal.

A base unit is the fundamental unit in a measurement system from which other units are derived. In the metric system, the meter is the base unit for length, the kilogram for mass, and the second for time. DiffMetric uses base units internally to ensure accurate conversions between any two units in the same category – we convert your input to the base unit first, then to your desired output unit.

Fuel economy can be expressed as distance per fuel volume (km/L, MPG) or fuel volume per distance (L/100km). These have an inverse relationship: higher MPG means better economy, but lower L/100km also means better economy. Converting between them requires division, not multiplication. For example: L/100km = 100 ÷ km/L. DiffMetric handles these inverse conversions automatically, including between US MPG (using US gallons) and UK MPG (using Imperial gallons).

Significant figures represent the precision of a measurement. If you measure something as 5.2 meters (2 significant figures), converting it doesn't make it more precise – 5.2m = 17.0604... feet, but should reasonably be reported as 17 feet. DiffMetric shows full precision so you can round appropriately for your needs. For scientific work, maintain only as many significant figures as your least precise measurement.

Some conversions involve irrational or repeating decimal numbers. For example, 1 inch = exactly 2.54 cm (by definition), but 1 foot = 0.3048 meters results in repeating decimals when reversed. Additionally, computers use binary floating-point arithmetic which can introduce tiny rounding differences (typically far smaller than any practical measurement). DiffMetric uses high precision internally to minimize these effects.

We use PHP's high-precision arithmetic and carefully manage floating-point calculations to minimize rounding errors. Internally, we maintain up to 15-20 significant digits of precision. Results are then formatted intelligently based on magnitude: large numbers show fewer decimal places, while small numbers show more. For extremely precise scientific work, we recommend using specialized calculation software.

Yes, DiffMetric uses scientifically accurate conversion factors suitable for most scientific and engineering applications. However, for mission-critical calculations, regulatory compliance, or research publications, we recommend: 1) Verifying conversion factors against primary standards documentation, 2) Considering the precision of your original measurements, 3) Using specialized scientific software for calculations requiring uncertainty analysis.

DiffMetric is designed to handle a wide range of values, from very small (0.000001) to very large (1,000,000,000+). We format numbers intelligently with appropriate decimal places and use thousands separators for readability. For extremely small or large values that would normally display in scientific notation (like 1.5e-10), we show the full decimal representation when practical.

Currently, DiffMetric is available as a web application only. We're exploring options for a public API in the future. If you're interested in API access for your application, please contact us to express your interest and help us understand your use case.

DiffMetric works on all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. We support the latest two major versions of each browser. The site uses progressive enhancement, so basic functionality works even in older browsers, though some visual features may be limited. JavaScript is required for the interactive converter features.

Temperature conversions are unique because they involve both multiplication/division AND addition/subtraction (offsets). For example, °F = °C × 9/5 + 32. Unlike length or weight conversions (which only multiply), temperature formulas require special handling. DiffMetric uses dedicated temperature conversion functions that correctly apply these formulas, including for Kelvin (which uses an offset from Celsius) and Rankine scales.

This usually happens when: 1) The input field is empty or contains non-numeric characters, 2) The value entered is extremely small and rounds to 0 at the displayed precision, 3) You're converting between units with a very large ratio (try a larger input value). Check that your input is a valid number without letters or special characters (except decimal points and minus signs for negative values).

Try these steps: 1) Refresh the page (Ctrl+R or Cmd+R), 2) Clear your browser cache and cookies, 3) Try a different browser, 4) Check your internet connection, 5) Disable browser extensions that might interfere. If the problem persists, please contact us with details about your browser and device.

We take accuracy very seriously! If you believe you've found an error, please contact us with: 1) The specific conversion page URL, 2) The value you entered, 3) The result you received, 4) What you believe the correct result should be, 5) Your source for the correct value. We'll investigate promptly and make corrections if needed.

Some physical quantities can't be negative – you can't have negative length, mass, or volume. However, temperature can be negative, so our temperature converters accept negative values. Similarly, some calculations like fuel economy require positive values to make physical sense. If you need to represent a negative quantity, consider what it means in your context.

The converter requires JavaScript to be enabled in your browser. Check that: 1) JavaScript is enabled in your browser settings, 2) No browser extensions are blocking scripts, 3) Your browser is up to date. The converter should update results in real-time as you type. If it doesn't respond, try refreshing the page or using a different browser.