Online Calculator Toolbox | Free Online Tools Collection

Online Calculate Tools

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Popular Tools

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Online CRC calculator supporting all standard algorithms: CRC-8, CRC-16, CRC-32, CRC-CCITT, MODBUS and more. Professional-grade error detection with custom polynomials.

Professional Modbus RTU online tool with three core functions: command generation, response data generation, and data analysis. Supports multiple data types (UINT16/INT16/UINT32/INT32/FLOAT32) and byte orders (ABCD/DCBA/BADC/CDAB).

Modbus RTU online debugging tool, supporting direct serial port connection in browser, real-time data collection, multi-format data parsing (binary/text), data visualization and export. Supports various data types (UINT16/INT16/UINT32/INT32/FLOAT32) and byte orders (ABCD/DCBA/BADC/CDAB), can be used with Modbus RTU tools for complete device debugging process.

Online time converter for timestamps, timezones, and multiple time formats. Convert between Unix timestamp, ISO 8601, RFC 3339 and custom formats.

Time Calculator

Calculate time intervals, date differences, and perform time arithmetic. Add or subtract days, hours, minutes with support for business days.

Satellite Time Converter

Professional satellite time system converter supporting GPS Time, BeiDou Time (BDT), GLONASS Time. Convert between different GNSS time systems.

Online AES encryption tool supporting 128/192/256-bit keys, multiple modes (CBC/ECB/CFB/OFB/CTR/GCM), and various padding methods. Professional cryptography calculator.

Cron Expression Generator

Free online Cron expression generator supporting Linux, Spring, Quartz and other formats. Provides visual configuration, expression validation, execution time preview, and detailed tutorials. Perfect for scheduling tasks and system configuration management.

Checksum Tools

Various checksum algorithm tools including XOR, LRC, CRC checksums

Online CRC calculator supporting all standard algorithms: CRC-8, CRC-16, CRC-32, CRC-CCITT, MODBUS and more. Professional-grade error detection with custom polynomials.

Checksum Calculator

Online checksum calculator. Calculate checksums by summing bytes for data verification. Simple and fast checksum calculation tool.

Online BCC (Block Check Character) and XOR checksum calculator. Calculate BCC checksums for data verification and error detection.

Online LRC (Longitudinal Redundancy Check) calculator. Calculate LRC checksum for data verification and error detection.

Adler32 Checksum

Online Adler32 checksum calculator and hash generator. Fast and reliable data integrity verification tool with RFC 1950 compliance.

Online parity calculator for odd and even parity checking. Calculate parity bits for error detection in data transmission.

Fletcher Checksum

Online Fletcher checksum calculator (16-bit and 32-bit). Fast and reliable error detection algorithm for data integrity verification.

Modbus Tools

Collection of various modbus protocol tools

Professional Modbus RTU online tool with three core functions: command generation, response data generation, and data analysis. Supports multiple data types (UINT16/INT16/UINT32/INT32/FLOAT32) and byte orders (ABCD/DCBA/BADC/CDAB).

Modbus RTU online debugging tool, supporting direct serial port connection in browser, real-time data collection, multi-format data parsing (binary/text), data visualization and export. Supports various data types (UINT16/INT16/UINT32/INT32/FLOAT32) and byte orders (ABCD/DCBA/BADC/CDAB), can be used with Modbus RTU tools for complete device debugging process.

Time Tools

Collection of time conversion, calculation, and processing tools

Online time converter for timestamps, timezones, and multiple time formats. Convert between Unix timestamp, ISO 8601, RFC 3339 and custom formats.

Time Calculator

Calculate time intervals, date differences, and perform time arithmetic. Add or subtract days, hours, minutes with support for business days.

Batch Time Converter

Convert multiple time formats in batch. Import/export time data with support for CSV, Excel, and custom formats.

Satellite Time Converter

Professional satellite time system converter supporting GPS Time, BeiDou Time (BDT), GLONASS Time. Convert between different GNSS time systems.

UTC to GPS Time

Online UTC to GPS time converter tool, supports Unix timestamp and datetime to GPS week number and time-of-week seconds, with leap second offset calculation.

Cron Expression Generator

Free online Cron expression generator supporting Linux, Spring, Quartz and other formats. Provides visual configuration, expression validation, execution time preview, and detailed tutorials. Perfect for scheduling tasks and system configuration management.

Encryption Tools

Collection of various encryption and decryption tools

Online Base64 encoding and decoding tool. Convert text and binary data to and from Base64 format. Support for UTF-8 and multiple character encodings.

Online AES encryption tool supporting 128/192/256-bit keys, multiple modes (CBC/ECB/CFB/OFB/CTR/GCM), and various padding methods. Professional cryptography calculator.

Online SM4 block cipher encryption tool. Chinese national standard symmetric encryption algorithm with multiple operation modes.

Online RSA encryption and decryption tool. Support 512/1024/2048/4096-bit keys, PKCS1/OAEP/NONE padding, PEM/HEX formats. Professional cryptography calculator.

Online SM2 public key cryptography tool. Chinese national standard encryption algorithm for digital signatures and key exchange.

Online Morse code converter. Translate text to Morse code and vice versa. Support for letters, numbers, punctuation with audio playback.

Hash Tools

Collection of various hash algorithm tools

Online hash calculator supporting MD5, SHA-1, SHA-2, SHA-3, RIPEMD160. Generate hash values for text and files with multiple output formats.

Online SM3 hash calculator. Chinese national standard cryptographic hash algorithm (GB/T 32905-2016).

HMAC Tools

Keyed-Hash Message Authentication Code Tools

Online HMAC calculator supporting MD5, SHA-1, SHA-2, SHA-3, RIPEMD160. Generate message authentication codes with custom keys.

Format Tools

Collection of data formatting tools

Online JSON formatter, validator and beautifier with syntax highlighting. Format, minify, and validate JSON data with error detection and tree view support.

Unit Converter

Collection of unit conversion tools, supporting length, weight, area and more

Weight Conversion

Online weight unit converter that supports precise conversion between over 40 weight units including grams, kilograms, ounces, pounds, tons, stones and more with professional results and reference knowledge.

Length Converter

Online length unit converter tool, supporting converter between meters, centimeters, millimeters, kilometers, inches, feet, yards, miles and other units, accurate and convenient.

Area Conversion

Online area unit converter that supports precise conversion between square meters, square kilometers, hectares, acres, square feet and more with professional results and reference knowledge.

Volume Conversion

Online volume unit converter that supports precise conversion between cubic meters, liters, cubic centimeters, gallons, cubic feet and more with professional results and reference knowledge.

Speed Conversion

Online speed unit converter for precise conversion between meters per second, kilometers per hour, miles per hour, knots, Mach and more with professional results and reference knowledge.

Temperature Conversion

Online temperature unit converter that supports precise conversion between Celsius, Fahrenheit, Kelvin, Rankine and other temperature scales, providing professional results and reference knowledge.

Time Conversion

Online time unit converter that supports precise conversion between seconds, minutes, hours, days, weeks, months, years and more, providing professional results and reference knowledge.

Energy Conversion

Online energy unit converter that supports precise conversion between joules, calories, kilowatt-hours, BTU and more energy units, providing professional results and reference knowledge.

Design Tools

Professional design tool collection including aspect ratio calculation, color processing, dimension conversion and other essential tools for designers

Aspect Ratio Calculator

Online aspect ratio calculator. Helps you calculate and adjust the aspect ratios of images and videos, resize while maintaining aspect ratio, supports common ratio presets.