Converters
Turn one representation into another on this device. Encoding is reversible and is not a cipher. Units use fixed factors, not live FX, including energy, pressure, angle, time units, cooking volume, fuel economy, force, frequency, and torque. Letter case rewrites characters without sending the string anywhere.
110 tools
Categories
Encoding
Open encoding converters for Base64, hex, URL percent-encoding, and HTML entities. If you need a checksum, use hash tools instead.
Units
The unit converter covers length, mass, temperature, volume, area, speed, data, energy, pressure, angle, time units, cooking, fuel economy, force, frequency, torque, and power. High-volume pairs such as inches to cm, Celsius to Fahrenheit, liters to gallons, square feet to square meters, mph to kph, MB to GB, and feet to yards are spokes of that engine. Dedicated hubs also exist for fuel economy, force, frequency, and torque.
Text and time
The case converter maps letters. Slugify and camel/snake rewrite identifiers. The time zone converter and world clock use IANA names. Word count lives under tools.
Encoding, units, and text
Color
Date and time
- Date Format Converter ISO, US, EU, RFC 1123, and Unix UTC midnight for a calendar date.
- Meeting Planner One instant in several zones for a meeting.
- Time Zone Converter Interpret the date and time as local in the from zone, then show it in the to zone. DST is the zone database in this browser.
- World Clock Times in selected IANA zones. One page, not a URL per city.
Base64
- Base64 Decoder Decode a Base64 string to UTF-8 text, hex, or another encoding. Invalid input fails with a clear error.
- Base64 Encoder Turn text or encoded bytes into Base64. Pick the input encoding and the alphabet your target system expects.
- Base64 to Hex Base64 to hexadecimal.
- Base64 to Image Preview an image from Base64 or a data URL.
- File to Base64 Any local file to Base64. Does not parse PDF structure.
- Image to Base64 Local image to a Base64 data URL. Nothing uploaded.
Encoding
HTML
- HTML Decoder Replace HTML 4 named character references and decimal or hex numeric references with the characters they stand for. Names are case-sensitive (Ω is not ω). Unknown names are left unchanged.
- HTML Encoder Turn the five HTML text specials into character references so the string can sit in HTML text. Named entities for ampersand, less-than, greater-than, and quotes; numeric ' for apostrophe. Other characters, including emoji, are left as they are.
URL
Numbers
- ASCII Code Converter Characters to code points and back.
- Number Base Converter Convert integers between bases 2 and 36.
- Number to Words Short-scale English cardinal words.
- Roman Numeral Converter Integers 1-3999 to canonical Roman numerals.
- Scientific Notation Converter Scientific and engineering notation.
- Words to Number Parse English cardinal words to an integer.
Text
- Caesar Cipher Toy Caesar cipher. Not for secrets.
- Camel Case to Snake Case Identifier case conversion.
- Case Converter Rewrite letter case in the paste you provide. Unicode letters follow the en-US locale rules in this browser.
- Morse Decoder Morse tokens separated by spaces.
- Morse Encoder International Morse. Space becomes / .
- Newline Converter newline convert in this browser.
- Remove Accents remove diacritics in this browser.
- Reverse Text reverse text in this browser.
- ROT13 ROT13. Symmetric. Not encryption.
- Slug Converter Lowercase, strip diacritics, hyphenate for URLs.
- Unicode Escape \uXXXX and \u{...} escape.
Angle
- Angle Converter Convert plane angles among degrees, radians, gradians, and turns. The browser uses Math.PI. A percent grade is a slope ratio, not a unit on this list.
- Decimal Degrees to DMS Converter Switch between decimal degrees and degrees-minutes-seconds (DMS). Default direction splits 30.5° into 30° 30' 0". Reverse direction rebuilds a decimal from D, M, and S.
Area
- Acres to Hectares Convert acres to hectares with the international foot. One acre is 4046.8564224 m². One hectare is 10000 m². So 1 ac = 0.40468564224 ha. This is not a cadastral survey.
- Area Converter Convert area units with fixed factors. Nothing uploaded.
- Square Feet to Square Meters Convert square feet to square meters with the international foot. One square foot is exactly 0.09290304 square meters. This is not a cadastral survey.
Data
- Bits to Bytes Convert bits to bytes. Eight bits make one byte. Kilobytes on this list use 1000. Kibibytes use 1024. Hard-drive marketing often uses 1000. RAM often uses 1024.
- Data Storage Converter Convert data units with fixed factors. Nothing uploaded.
- MB to GB Convert megabytes to gigabytes using SI prefixes: 1000 MB = 1 GB. Switch to mebibytes and gibibytes when you need 1024. This is storage size, not download time.
Energy
- Energy Converter Turn a stored quantity of energy into another unit. The SI unit is the joule. This is not a power converter and it does not turn watt-hours into milliamp-hours.
- Joules to kWh Convert joules to kilowatt-hours. 3,600,000 J equals 1 kWh. Default input 3,600,000 J. For utility and physics comparisons.
- kWh to Joules Convert kilowatt-hours to joules. One kWh is exactly 3,600,000 J (3.6 MJ). Default input 1 kWh. Energy units only, not power.
- mAh to Wh Convert milliamp-hours to watt-hours using voltage: Wh = (mAh / 1000) × V. Default 5000 mAh at 3.7 V is 18.5 Wh. Voltage is required. Not on the energy hub without voltage.
- Watt-Hours to mAh Convert watt-hours to milliamp-hours using a voltage you type. Wh = (mAh / 1000) × V. Milliamp-hours are charge, not energy, until you multiply by volts. The energy hub does not list mAh.
Length
- AWG to mm² Convert American Wire Gauge to conductor cross section in mm² using ASTM B258. Gauge 4/0 is n = -3. This is diameter geometry, not a code ampacity table.
- Centimeters to Inches Centimeters to inches. 1 in = 2.54 cm.
- Feet and Inches Calculator Convert feet plus inches to decimal feet, total inches, centimeters, and meters. Split total inches into feet and leftover inches. Add or subtract two lengths. No adult-height 9 ft cap. Construction helper, not a growth chart.
- Feet to Centimeters Convert international feet to centimeters. One foot is exactly 30.48 cm. Type a decimal foot such as 5.5, not 5 feet 6 inches as two fields.
- Feet to Inches Feet to inches. 1 ft = 12 in.
- Feet to Meters Feet to meters. 1 ft = 0.3048 m.
- Feet to Millimeters Convert international feet to millimeters. One foot is exactly 304.8 mm. Type a decimal foot. Feet plus leftover inches as two fields belong on the height converter.
- Feet to Yards Convert feet to yards. Three international feet make one yard exactly. This page does not use the US survey foot. Height in feet and inches is a different job.
- Height Converter Feet and leftover inches to centimeters, or centimeters to feet and inches. Same inch factor as the length converter.
- Inches to Centimeters One inch is 2.54 centimeters exactly. This page locks those two units on the shared length engine.
- Inches to Feet Convert inches to international feet. Twelve inches make one foot. Both units rest on the 1959 inch of 0.0254 m. The list still holds millimeters, meters, yards, miles, and nautical miles.
- Inches to Meters Convert inches to meters. One inch is exactly 0.0254 m. This is the SI definition of the international inch, the same inch as inches to centimeters.
- Inches to Millimeters Inches to millimeters.
- Kilometers to Miles Kilometers to statute miles.
- Length Converter Convert a length with SI factors. One inch is 0.0254 meters exactly. For height in feet and inches, use the height page.
- Meters to Feet Meters to feet.
- Miles to Kilometers Convert statute miles to kilometers. One international mile is exactly 1.609344 km. Nautical miles (1852 m) sit on the same list under a different label.
- Millimeters to Inches Millimeters to inches.
- Shoe Size Converter Convert adult shoe sizes among US men, US women, UK, EU, and Mondopoint millimeters. The model uses last length: EU Paris point of 2/3 cm, UK barleycorn, US men = UK + 1, US women = US men + 1.5. Brands differ. This is not a fitting.
Mass
- Grams to Kilograms Convert grams to kilograms. One kilogram is 1000 grams exactly. This is the SI prefix, not a density tool and not a force converter.
- Grams to Ounces Grams to avoirdupois ounces.
- Kilograms to Pounds The pound is 0.45359237 kg exactly. This page locks kg to lb on the shared mass engine.
- Kilograms to Stone Kilograms to stone. 1 st = 6.35029318 kg.
- Pounds to Kilograms Multiply pounds by 0.45359237. Same mass engine as kilograms to pounds.
- Weight and Mass Converter Avoirdupois pound is 0.45359237 kg. Metric prefixes from the gram. Not a planetary gravity tool.
- Ounces to Grams Convert avoirdupois ounces to grams. One ounce is 1/16 of the international pound, so 1 oz = 28.349523125 g. Troy ounces for precious metal are not on this list.
- Ounces to Pounds Convert avoirdupois ounces to pounds. Sixteen ounces make one pound. This is mass, not US fluid ounces of volume.
- Stone to Kilograms Convert stone to kilograms. One stone is exactly 14 avoirdupois pounds, which is 6.35029318 kg. This is mass, not kilogram-force.
- Stone to Pounds Convert stone to avoirdupois pounds. One stone is exactly 14 pounds. Decimal stone such as 11.5 st is 161 lb. This page does not split 11 st 6 lb into two boxes.
Power
- Horsepower to Kilowatts Mechanical horsepower to kilowatts.
- Kilowatts to Horsepower Convert kilowatts to mechanical horsepower. One mechanical horsepower is 745.6998715822702 W, so 1 kW is about 1.341022 hp. This is the reverse of horsepower to kilowatts.
- Megawatts to Kilowatts Convert megawatts to kilowatts. One megawatt is 1000 kilowatts exactly. Mechanical horsepower is on the same list. This is power, not megawatt-hours of energy.
- Power Converter Convert power units with fixed factors. Nothing uploaded.
Pressure
- Bar to PSI Convert bar to pound-force per square inch. One bar is exactly 100000 Pa. One PSI is 6894.757293168 Pa. This page does not add atmospheric pressure.
- Pressure Converter Convert a pressure number between pascals, kilopascals, bar, PSI, standard atmospheres, and torr. This page does not add or subtract atmospheric pressure, and it is not a weather station.
- PSI to Bar Convert pound-force per square inch to bar. One PSI is 6894.757293168 Pa. One bar is 100000 Pa. This is the reverse of bar to PSI and does not add atmosphere.
Speed
- KPH to MPH Convert kilometers per hour to miles per hour. Divide km/h by 1.609344, the exact international-mile factor. Defaults start at km/h, the reverse of the mph to kph spoke.
- MPH to KPH Convert miles per hour to kilometers per hour. One international mile is 1609.344 m, so 1 mph = 1.609344 km/h exactly. This is not a speed camera.
- Speed Converter Convert speed units with fixed factors. Nothing uploaded.
Temperature
- Celsius to Fahrenheit Multiply by 9/5 and add 32. Locked spoke of the temperature converter.
- Celsius to Kelvin Convert Celsius to kelvin with the offset K = C + 273.15. Absolute zero is 0 K, which is -273.15 °C. The engine rejects temperatures below that.
- Fahrenheit to Celsius F = C × 9/5 + 32 reversed.
- Temperature Converter F = C × 9/5 + 32. K = C + 273.15. Values below 0 K are rejected.
Volume
- Gallons to Liters Convert US gallons to liters. One US gallon is exactly 3.785411784 liters. The UK gallon is listed as Gallons (UK). This is the reverse of liters to gallons.
- Liters to Gallons Convert liters to US gallons. One US gallon is exactly 3.785411784 liters. The UK gallon is listed as Gallons (UK). This is liquid volume, not a dry measure.
- Milliliters to Fluid Ounces Convert milliliters to US fluid ounces. One US fluid ounce is 29.5735295625 ml. This is liquid volume, not the 28.35 g avoirdupois ounce.
- Volume Converter Convert volume units with fixed factors. Nothing uploaded.
Converter questions
Does a converter upload my text?
No. Conversion runs in the page you opened. CZNull does not receive the input.
Is Base64 encryption?
No. Anyone can decode it. Use it to carry bytes through text systems, not to hide secrets.