Online Converter Tools
Units, Numbers And Time
These free online converter tools change units, number bases, dates and CSS sizes. Each converter shows the formula, so you can trust the result.
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What These Online Converter Tools Do
A converter should be fast and exact. So each of these online converter tools answers as you type, and it shows the factor it used. First, the unit converters cover length, weight, area, volume, speed and temperature.
Then come the converters for numbers. For instance, the number base converter moves between binary, octal, decimal and hex, the Roman numeral converter works both ways, and the number to words converter spells a number out.
Finally, a few converter tools help on the web. The px to rem converter sizes CSS, the Unix timestamp converter reads server dates, and the IP address converter changes formats. In addition, two marketing calculators work out CPM, CPC and conversion rate.
Which converter do you need? For everyday units, start with the unit converter, which covers many kinds of measures on one page. For a single kind, such as temperature or speed, the dedicated converter shows more detail and the exact formula.
Web work has its own conversions. The px to rem converter keeps a design in step with the reader's font size, and the Unix timestamp converter turns server times into readable dates. Meanwhile, the IP address converter helps when a log stores addresses as numbers.
Each converter rounds only at the end, so long chains of sums stay exact. You can also copy the result with one click. Because the tools run in your browser, they work on a plane, on a train or anywhere without a signal.
Many of these converters also explain themselves. Each page shows the formula next to the answer, plus a short table of common values. As a result, the converters are handy for homework and for checking a figure in a report, not only for quick answers.
If you convert the same values often, keep the page open in a tab. It remembers nothing and needs no account, yet it loads in a moment and answers as fast as you can type.
More free tool categories
All Free Converter Tools On This Page
Units first, then numbers, time and marketing sums.
Converter and number tools
Units, number bases, dates and addresses, turned from one form into another.
- Unit Converter
Convert length, weight, temperature, volume, speed and more.
- Temperature Converter
Turn Celsius, Fahrenheit, Kelvin and Rankine into one another, with the formula shown.
- Length Converter
Turn metres, feet, inches, miles and more into one another, with the exact factor shown.
- Weight Converter
Turn kilograms, pounds, ounces, stones and tons into one another, with the exact factor shown.
- Area Converter
Turn square meters, square feet, acres and hectares into one another, with the exact factor shown.
- Volume Converter
Turn liters, US and imperial gallons, pints and cubic feet into one another, with the exact factor shown.
- Speed Converter
Turn km/h, mph, meters per second and knots into one another, with the exact factor shown.
- Px To Rem Converter
Convert px, rem, em, pt, percent and viewport units, or a whole piece of CSS.
- Number Base Converter
Binary, octal, decimal, hex or any base to 36, exact even for huge numbers, with every step shown.
- Roman Numeral Converter
Turn numbers and dates into Roman numerals and back, with every symbol explained and loose forms caught.
- Number to Words Converter
Then write any amount in words in six languages, for cheques and invoices.
- Bitwise Calculator
Then run AND, OR, XOR, NOT and shifts on 8 to 64 bit numbers.
- IP Address Converter
Next, turn IPv4 and IPv6 addresses into decimal, hex, binary, short and full forms.
- Unix Timestamp Converter
Also turn epoch numbers into dates in any time zone and back, with exact milliseconds and clock changes caught.
- Random Number Generator
Also pick random whole numbers, decimals, primes, bytes and strings from a secure source.
Marketing calculator tools
Two sums worth doing before you spend, and again after.
- CPM and CPC Calculator
Turn spend, impressions, clicks and conversions into seven campaign numbers. Above all, each one shows its formula.
- Conversion Rate Calculator
Work out your rate, the value per visitor and the gap to a target. Similarly, compare two variants of a test.
Questions about these converter tools
Are these online converter tools free?
Yes. Every converter here is free, with no sign-up and no ads in the way.
How exact are the results?
Each converter uses the standard factor and shows it. Therefore you can check any result by hand.
Which converter turns px into rem?
The px to rem converter. Set the base font size, then convert one value or a whole piece of CSS.
Do the converters work on a phone?
Yes. Every converter fits a small screen and works offline after the page loads.
Can I convert between metric and imperial units?
Yes. Every unit converter works both ways, for example meters to feet and feet to meters.
How do I read a Unix timestamp?
Paste it into the Unix timestamp converter. It shows the date and time in your time zone and in UTC.
What does the number base converter do?
It turns a number between binary, octal, decimal and hex, and it shows each step.
Can I work out ad costs here?
Yes. The CPM and CPC calculator and the conversion rate calculator do the sums for a campaign.
Is there a converter for screen sizes?
Yes. The px to rem converter turns pixel sizes into rem, em, points and viewport units for CSS.
Can I convert Roman numerals?
Yes. The Roman numeral converter works both ways, from numbers to numerals and back.
Can I convert temperatures with decimals?
Yes. Type any value, with or without decimals, and the temperature converter shows Celsius, Fahrenheit, Kelvin and Rankine at once.