AI / Tool
Bilingual Tone Checker
Paste a message, see how warm, formal, or direct it reads.
kbwen Lab
Quick answers, no sign-up.
33 browser tools for quant math, dev tasks, Taiwan formats, and the occasional game.
Featured Tools
The ones people come back to most. Updated based on usage.
Quant / Calculator
Compound Interest / CAGR Calculator
Model compound growth or reverse-calculate CAGR.
Dev / Json
JSON Formatter
Pretty-print, minify, or validate JSON with error location hints.
Games / Board Game
Gomoku
Play gomoku against AI with live threat visualization that teaches you board patterns as you play.
Local / Taiwan
Taiwan ID Validator
Check Taiwan national ID format, checksum, and prefix.
Design / Tool
Color Converter
Convert between HEX, RGB, and HSL live — with WCAG contrast ratios and nearest CSS color name.
Text / Tool
Character Word Counter
Count characters, words, and reading time as you type.
Time / Tool
Unix Timestamp Batch Converter
Paste a list of timestamps and convert them all at once, with relative time and a timeline view.
Learn / Education
Forgetting Curve Vocab
Learn English vocabulary using Ebbinghaus forgetting curve spaced repetition. 5 minutes a day with pronunciation and example sentences.
Explore by Category
Pick a lane and see what’s inside.
Category 1 tool
AI
Tone checks, prompt helpers, bilingual writing aids.
Category 3 tools
Quant
Compound interest, Kelly criterion, and DCA calculators.
Category 8 tools
Dev
JSON, Base64, HTML entities, markdown, character counts.
Category 7 tools
Games
Word puzzles, number merge, arcade — no install needed.
Category 4 tools
Local
Taiwan ID, invoice, year converters, and everyday local tools.
Category 2 tools
Design
Color converters, aspect ratios, gradients, and visual helpers.
Category 2 tools
Text
Character counts, markdown cleanup, case conversion.
Category 2 tools
Time
Timestamps, timezones, countdowns, and date math.
Category 4 tools
Learn
Vocabulary drills, algorithm visualizers, and interactive learning.
Frequently Asked Questions
What is kbwen Lab?
kbwen Lab is a collection of free, lightweight browser tools for quant math, developer tasks, Taiwan-specific formats, and casual games. All tools run entirely in your browser with no sign-up required.
Are all tools free?
Yes. Every tool on kbwen Lab is free to use with no account needed.
Is my data private?
All tools run locally in your browser. Your data never leaves your device unless a tool explicitly states otherwise.
Do I need to create an account?
No. All tools work instantly in your browser — no sign-up, no login, no installation.
What categories of tools are available?
kbwen Lab covers nine categories: AI, quant, dev, games, local, design, text, time, and learning tools.
Can I use these tools on my phone?
Yes. All tools are responsive and work on mobile browsers. No app download is needed.