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Online conversion and calculation tools

Convert file sizes, bases, physical units and timestamps, calculate dates, factorials and IPv4 subnets, and convert data between JSON, YAML and XML.

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  • Unix timestamp conversion

    Convert Unix seconds or milliseconds to dates and back, with ISO output and a chosen time zone. The Unix epoch starts at 1970-01-01 00:00:00 UTC; a time zone changes the display, not the timestamp of the same instant.

  • JSON/YAML conversion

    Good for converting interface examples and configuration data: preserving large integers, exact decimals, and string types without reserializing numbers through JavaScript floats.

  • File size conversion

    Convert file sizes between bytes, KB, MB, GB and binary units such as KiB, MiB and GiB. Supports decimal and scientific notation, with separate 1000-based and 1024-based unit tables.

  • IP/Subnet Computing

    Calculate an IPv4 network address, subnet mask, broadcast address, usable IP range and host count from CIDR notation. Supports /0–/32 and preset masks; this is a calculator, not a network scanner.

  • Number formatting

    Format decimal numbers with thousands separators, scientific notation, percentages, currency display and Chinese number words. Large integers and decimals retain precision; currency formatting does not convert exchange rates.

  • Base conversion

    Accurately convert binary, octal, decimal, hexadecimal and base 2–36 integers. Supports positive and negative numbers and large integers, strictly checks each digit, and provides quick selection of commonly used bases.

  • Unit conversion

    Convert meters, inches, kilograms, pounds, US volume and temperatures in Celsius, Fahrenheit and Kelvin. Select the original unit and target unit by category, and provide common combination and exchange unit functions.

  • XML/JSON conversion

    Convert between XML and JSON objects, using @_ for attributes, #text for text, and preserving numeric strings such as 00123. Explicitly note conversion loss for annotations, CDATA, and mixed content.

  • Factorial Calculator

    Exactly compute integer factorials from 0 to 5000 without losing large integer digits.

  • date calculator

    Calculate the number of days between two calendar dates, or add or subtract days to a date.

  • Original code, inverse code and complement code

    View the sign bit representation, one's complement, and two's complement representation of an integer with a specified word length.

How to choose

processing capacity or value
Use the file size converter for KB and KiB, the base converter for integer number bases, and the number formatter for thousands separators and percentages. Use the unit converter for length, mass, volume and temperature.
Transform data structures
JSON/YAML transformation is suitable for configuration data; XML/JSON transformation is not guaranteed to preserve the full semantics of XML mixed content. Please check the data type and content after conversion.
Check network information
The IPv4 subnet tool only calculates the address range, mask, and number of hosts. It does not scan the network or detect whether the address is online.