Free Converter Tools Online
6 converter tools. Units, currencies, timezones, and more.
Unit Converter
converterConvert between 100+ units across 12 categories: length, weight, temperature, volume and more.
Use toolScientific Calculator
converterFull-featured scientific calculator with trig functions, logarithms, history and memory.
Use toolAge Calculator
converterCalculate exact age in years, months, days, hours and seconds. Includes birthday countdown and zodiac sign.
Use toolTimezone Converter
converterConvert time between world timezones. Compare multiple zones with business hours indicator.
Use toolRoman Numeral Converter
converterConvert numbers to Roman numerals and Roman numerals to numbers. Supports 1–3,999,999 with batch conversion.
Use toolPercentage Calculator
converterCalculate percentages: X% of Y, percentage change, discount, tax, and percentage difference. 5 modes.
Use toolAbout These Converter Tools
Privatool's converter tools handle the most common unit and format conversion tasks without any setup. The Unit Converter covers length, weight, temperature, area, volume, speed, and digital storage. The Timezone Converter uses the browser's Intl API for DST-aware time conversion between any two zones. The Age Calculator shows exact age in years, months, days, and hours. The Roman Numeral Converter handles numbers up to 3,999,999 using vinculum notation. The YAML to JSON Converter and Scientific Calculator round out the set. All tools run entirely in the browser with instant results and no server round trip.
Why Use Browser-Based Converter Tools?
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Instant conversion
Results update in real time as you type — no button, no page reload.
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DST-accurate
Timezone converter uses Intl API for accurate daylight saving time handling.
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No ads in the tool
Clean interface focused on the conversion, not on monetising your attention.
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Works offline
All converters work without internet once the page has loaded.
Related Guides
Frequently Asked Questions
What units does the Unit Converter support?
The Unit Converter supports length (meters, feet, inches, miles, km), weight (kg, lb, oz, stone), temperature (Celsius, Fahrenheit, Kelvin), area, volume, speed, and digital storage (bytes, KB, MB, GB, TB). Switch between categories using the dropdown.
How does the Timezone Converter handle daylight saving time?
The Timezone Converter uses the browser's Intl API which automatically applies the correct DST rules for each timezone based on the selected date. This ensures the conversion is accurate year-round, not just during standard time.
What does the Age Calculator show beyond just years?
The Age Calculator shows your exact age in years, months, days, hours, and minutes as of today (or any target date you set). It also shows the day of the week you were born and how many days remain until your next birthday.