Frequently Asked Questions
Everything you might want to know about Quick Unit Convert: how it works, what it costs, which units it supports, and how we handle your privacy. Still have a question? We are happy to help on our contact page.
Is Quick Unit Convert really free?
Yes. Every converter on the site is completely free to use, with no usage limits, no trial period, and no premium tier hiding the useful features behind a paywall. You can run as many conversions as you like, across every category, without ever paying anything. The site is supported by unobtrusive advertising rather than subscriptions, which lets us keep the tool open to everyone.
Do I need to create an account or sign up?
No. There are no accounts, no sign-up, no login, and no newsletter. You can open any converter and start using it immediately. We deliberately avoid collecting personal details because a unit converter simply does not need them. Just visit a page, type a number, and read the result.
How accurate are the conversions?
Conversions are based on standard, internationally recognized conversion factors, and the math runs at full double-precision floating point in your browser. For everyday and most professional purposes the results are exact to far more decimal places than you will ever need. The only thing to keep in mind is ordinary rounding. When a result is displayed it may be rounded for readability, and tiny floating-point artifacts can appear in the final digits of very long decimals. If you need a specific precision for engineering or scientific work, copy the full value and round it yourself to the number of significant figures your task requires.
Which categories and units are supported?
Quick Unit Convert covers 14 measurement categories: Length, Area, Volume, Weight, Temperature, Speed, Time, Data, Pressure, Energy, Power, Angle, Frequency, and Flow Rate. Each category contains a generous set of metric and imperial units, plus common scientific and digital units such as joules, watts, pascals, radians, hertz, and bytes. You can browse the full list of categories on the converter overview page and pick the one you need. If a unit you rely on is missing, we would genuinely like to hear about it.
How do I convert one unit to another?
Open the category you need, choose your starting unit and target unit from the dropdowns, and type a value. The result updates as you type, so there is no submit button to press. Every conversion also lives at a predictable URL, which makes it easy to jump straight to a specific pairing. The pattern is /converter/<category>/<from>/to/<to>. For example, /converter/length/m/to/ft opens meters to feet, and /converter/weight/kg/to/lb opens kilograms to pounds.
Can I share or bookmark a specific conversion?
Yes, and this is one of the most useful features. Because each conversion has its own clean URL, you can bookmark a pairing you use often or copy the link from your address bar and send it to someone else. When they open it, the converter loads with the same category and units already selected. This makes it simple to keep, say, a kilometers-to-miles or Celsius-to-Fahrenheit page one click away.
Does it work offline and on mobile?
The site is fully responsive and designed to work well on phones, tablets, and desktops. The dropdowns and input fields are large enough to use comfortably with a touchscreen, and the layout adapts to narrow screens. All the conversion math happens directly in your browser, so once a converter page has loaded it does not need to contact a server to calculate results. You will still need an internet connection to open a page for the first time, but the actual converting is instant and local.
What is the difference between metric and imperial units?
The metric system (also called SI) is a decimal system used by most of the world. It scales in powers of ten, so a kilometer is 1,000 meters and a kilogram is 1,000 grams. This makes mental conversion within the system straightforward. The imperial system, common in the United States and a few other places, uses units like inches, feet, miles, ounces, and pounds, which relate to one another by less regular factors (12 inches to a foot, 5,280 feet to a mile). Quick Unit Convert handles both systems and converts freely between them, so you never have to memorize those factors yourself.
How is temperature converted if it is not a simple ratio?
Most conversions are linear: to change meters into feet you multiply by a single factor. Temperature is different because the scales do not share a common zero point. Zero degrees Celsius is not zero degrees Fahrenheit, so a plain multiplication would give the wrong answer. Instead, temperature uses formulas that include both a scaling step and an offset. Converting Celsius to Fahrenheit, for instance, multiplies by 9/5 and then adds 32, while Kelvin shifts the Celsius scale by 273.15. Our temperature converter applies these formulas correctly for you, so Celsius, Fahrenheit, and Kelvin always line up. You can try it on the temperature converter.
Do you store my data or track what I convert?
We do not store the values you convert on any server, and we do not require any personal information to use the tool. The only thing the site keeps on your device is a single temporary value in your browser's session storage, which exists so that the number you typed is preserved when you swap the "from" and "to" units. It is cleared when you close the tab. For full details on what is and is not collected, see our privacy policy.
Why do I see ads on the site?
Advertising is what keeps Quick Unit Convert free and account-free. Rather than charging a subscription or locking features behind a paywall, we display ads through Google AdSense to cover the costs of running and improving the site. We aim to keep them reasonable and out of the way of the actual converter, so they should never get in the way of getting a quick answer.
Can I use the conversions for professional or scientific work?
For the vast majority of professional, academic, and everyday tasks the results are reliable and precise. That said, we provide the tool as a convenience and cannot guarantee suitability for high-stakes work such as medical dosing, structural engineering, or legal measurements. For critical applications, always double-check important figures against an authoritative reference or an independent calculation before you rely on them.
How does the converter actually work behind the scenes?
Each unit is defined relative to a base unit within its category, and converting from one unit to another is a matter of translating your value into that base unit and then out to the target. All of this runs client-side in your browser the moment you type, which is why results appear instantly. If you are curious about the details, we explain the approach in plain language on the how it works page.
I found an error or want a new unit added. What do I do?
Please tell us. If a result looks wrong, or a unit or category you need is missing, reach out through our contact page and describe what you were trying to convert. Real feedback from people who use the tool is the best way for us to catch mistakes and decide which units to add next, so we read and appreciate every message.
What browsers and devices are supported?
Quick Unit Convert works in any modern browser, including recent versions of Chrome, Firefox, Safari, and Edge, on Windows, macOS, Linux, Android, and iOS. Because the site relies on standard web technology and does not require plugins or installation, you do not need to download anything. Just open a page and start converting.
Ready to convert something?
Jump straight into the tool and pick from all 14 categories, or learn more about the project before you start.