Developer Tools
51 free online calculators — instant results, no sign-up
Base Converter for DevelopersBinary, octal, decimal, hex — batch conversionColor Code ConverterHEX, RGB, HSL and CMYKJSON FormatterBeautify, minify and validate JSONBase64 Encoder / DecoderEncode and decode Base64 textURL Encoder / DecoderencodeURI and decodeURI onlineUnix Timestamp ConverterTimestamp ↔ date conversionRegex TesterTest regular expressions with match highlightingHash CalculatorMD5 and SHA-256 hashing onlineCharacter CounterWords, characters, lines and bytesLorem Ipsum GeneratorPlaceholder text with custom paragraph countMarkdown PreviewLive rendering with syntax highlightingNEWText Diff ToolLine-by-line comparison with highlighted changesNEWHTML Entities ConverterCharacters ↔ HTML entity codesUUID GeneratorBatch UUID v4 generation with multiple formatsQR Code GeneratorText, links and WiFi to QR code with PNG downloadCron Expression ParserHuman-readable meaning and next 10 run timesSubnet CalculatorIP/CIDR to mask, broadcast and usable hostsChmod Calculatorrwx checkboxes to octal and symbolic notationCase ConvertercamelCase, snake_case, kebab-case and 7 more stylesUnicode Code Point LookupCharacter to U+ code point, UTF-8 bytes and HTMLJWT DecoderDecode header/payload, inspect claims and expirypx ↔ rem ConverterRoot font-size based conversion with common scale tableASCII Code TableChar ↔ code in dec/hex/oct with full printable tableDownload Time CalculatorFile size over bandwidth to transfer durationUptime SLA CalculatorAvailability percentage to allowed downtime per yearAspect Ratio CalculatorSimplify ratios and scale dimensions proportionallyCSV ↔ JSON ConverterTwo-way conversion, RFC 4180 quote escapingColor Contrast CheckerWCAG AA/AAA ratios via relative luminanceText Line ToolsDedupe, sort, trim, remove empty and number linesURL Slug GeneratorTitle → lowercase hyphenated slug, accents strippedMorse Code TranslatorText to Morse, audio playback, reference chartHTTP Status Codes1xx-5xx lookup by category with meaningsBitwise CalculatorAND/OR/XOR, shifts, bit visualizationIEEE 754 AnalyzerFloat32/64 bit layout and precisionURL ParserSplit protocol/host/query paramsCommon Port Reference40+ ports, searchableMeta Tag GeneratorOG/Twitter tags, one-click copyOpen Source License PickerComparison table, wizard recommendationEAN-13 Barcode ToolChecksum validate & generate, prefix tableSQL FormatterUppercase keywords, indent, minifyMojibake Fixerlatin1/GBK/UTF-8 fix, hex decodeYAML ↔ JSON ConverterTwo-way with line-numbered errorsJSON to TypeScriptGenerate interfaces from JSONAES Encryption ToolAES-256-GCM/CBC, local PBKDF2XML FormatterBeautify/minify + tag validationHMAC GeneratorHMAC-SHA family + Hex/Base64robots.txt GeneratorUA rules + AI bots + SitemapChinese ID Card ValidatorGB11643 checksum + region parsingUser-Agent ParserBrowser/OS/device · bot detectionTraditional-Simplified ConverterChinese char + word-level mappingUTM Link BuilderCampaign URL tagging · presets · copy