Technology cluster
Developer Tools & Converters
Encoders, decoders, format converters, and generators for developers: base64, hex, JSON, hashes, ciphers, UUIDs, plus API and software cost calculators.
Top calculators
A short starting set for the most common developer tools & converters workflows.
Keyboard Keycode Viewer (JavaScript Keyboard Event Inspector)
Press any key to instantly inspect JavaScript KeyboardEvent values such as event.key, event.code, and legacy event.keyCode. Includes copy-to-clipboard help, worked examples, and an optional mini-game.
XML Formatter, Minifier and Well-Formedness Validator
Format, minify, and validate XML well-formedness in your browser. Locate parser errors, inspect namespaces and document metrics, and preserve mixed content without uploading data.
Browser Barcode Generator for UPC-A, EAN-13, and Code-128 Labels
Create UPC-A, EAN-13, and Code-128 barcode previews in your browser, copy the encoded data, and download a PNG image for label tests, inventory, and shipping.
NATO Phonetic Converter for Text, Code Words, and Aviation Digits
Convert letters and digits into ICAO/NATO phonetic code words, or decode recognized code words and aviation number words back into text for clear radio spelling.
.gitignore Builder - Combine Project Ignore Rules
Build a project-specific.gitignore by combining language, tool, IDE, operating-system, and custom ignore patterns.
Live Audio Spectrum Analyzer & 5-Second Microphone Recorder
View the live frequency spectrum from your microphone, identify low-to-high frequency energy, and save a five-second WebM audio recording in your browser.
Braille Translator for Unicode Braille Encoding and Decoding
Convert text to Unicode Braille and decode Braille back to text, and see how the capital sign, the number sign and the six-dot cell work.
API Usage Cost Calculator for Per-Request Billing
Estimate API spend from per-1,000-request pricing, average daily calls, active days, and month-over-month growth before you set a budget.
All calculators in this cluster
Browse 19 calculators matched to this topic, or return to the Technology category.
.gitignore Builder - Combine Project Ignore Rules
Build a project-specific.gitignore by combining language, tool, IDE, operating-system, and custom ignore patterns.
API Rate Limit Planner - Request Interval and Burst Batch Time
Plan API request intervals from a per-minute limit and estimate batch completion time after an available burst allowance.
API Security Risk Estimator for Public Endpoints and Auth Strength
Estimate API security risk from public endpoint count, data sensitivity, and authentication strength, then compare low, moderate, and high exposure scenarios.
API Usage Cost Calculator for Per-Request Billing
Estimate API spend from per-1,000-request pricing, average daily calls, active days, and month-over-month growth before you set a budget.
Base-N Number Converter for Bases 2โ36
Convert whole numbers between bases 2 and 36 in your browser, see how positional notation works, and review the limits and examples for base-N conversion.
Braille Translator for Unicode Braille Encoding and Decoding
Convert text to Unicode Braille and decode Braille back to text, and see how the capital sign, the number sign and the six-dot cell work.
Browser Barcode Generator for UPC-A, EAN-13, and Code-128 Labels
Create UPC-A, EAN-13, and Code-128 barcode previews in your browser, copy the encoded data, and download a PNG image for label tests, inventory, and shipping.
Bug Fix Priority Score Calculator โ Severity, User Impact & Fix Effort
Calculate a bug fix priority score by dividing severity times affected users by estimated fix hours for consistent software issue triage.
Clothing Size Converter: US, UK, EU, Italy and Japan
Convert clothing and shoe sizes between the US, UK, EU, Italian and Japanese systems for dresses, jackets, trousers, shirts and shoes, with body measurement bands.
Data Storage Converter: Bits, Bytes, KB, MB, GB & More
Convert digital storage between bits, bytes, KB, MB, GB, TB and the binary units KiB, MiB, GiB and TiB using exact byte factors, with a formula and a worked example.
Hash Collision Risk Calculator | Birthday-Bound Estimate
Estimate the chance that at least two generated hash values collide from the number of hashes and hash output bit size, using the birthday-bound approximation.
Keyboard Keycode Viewer (JavaScript Keyboard Event Inspector)
Press any key to instantly inspect JavaScript KeyboardEvent values such as event.key, event.code, and legacy event.keyCode. Includes copy-to-clipboard help, worked examples, and an optional mini-game.
Live Audio Spectrum Analyzer & 5-Second Microphone Recorder
View the live frequency spectrum from your microphone, identify low-to-high frequency energy, and save a five-second WebM audio recording in your browser.
Lottery Number Generator - Random Picks for Popular Games
Create random lottery ticket numbers for Powerball, Mega Millions, and EuroMillions. Learn about odds, combinations, and responsible play.
NATO Phonetic Converter for Text, Code Words, and Aviation Digits
Convert letters and digits into ICAO/NATO phonetic code words, or decode recognized code words and aviation number words back into text for clear radio spelling.
Open Source License Compatibility Checker for Project Dependencies
Compare a project's MIT, Apache-2.0, GPL, BSD, or LGPL license with a dependency using this simplified open-source license compatibility matrix.
Shoe Size Converter: US, UK, EU & Japan Chart Lookup
Use this shoe size converter to look up the chart row for a US, UK, EU, or Japanese size and compare its listed international equivalents.
Torque Converter Efficiency Calculator | Slip, Speed Ratio & Lock-Up
Estimate torque converter efficiency from engine RPM, turbine/output RPM, and slip percentage. Compare implied slip, see how lock-up changes the estimate, and review the limits of the calculator.
XML Formatter, Minifier and Well-Formedness Validator
Format, minify, and validate XML well-formedness in your browser. Locate parser errors, inspect namespaces and document metrics, and preserve mixed content without uploading data.