Free Online Tools — Nothing to Install, Nothing Leaves Your Browser
Every tool listed here runs entirely in your browser: no sign-up, no installation, and no file uploads to a server. Open a tool, use it, close the tab — that's the whole workflow. It also makes them fast: nothing to install, no account to create, no upload queue. Paste or type, copy the result out, and the round trip takes seconds.
Markdown Editor Online
A full-featured Markdown editor with a live side-by-side preview. Write, format and export without installing anything — useful for README drafts, release notes, or checking how Markdown renders before you publish it anywhere.
Simplified-Traditional Chinese Converter
Convert Chinese text between Simplified and Traditional in real time, with Taiwan and Hong Kong vocabulary variants. Phrase-level conversion via OpenCC dictionaries means ambiguous characters like 发 → 發/髮 land on the right form automatically — and everything runs locally in your browser.
Chinese to Pinyin
Paste Chinese text and get Mandarin pinyin (tone symbols, numbers or plain — with case and separator options), Cantonese Jyutping and Wubi 86/98 input codes, all three at once. Word-level segmentation keeps polyphonic characters like 重庆 chóng qìng and 银行 yín háng right, and everything converts locally in your browser.
Date Calculator
How many days between two dates, how many weekdays, and what date is N days/weeks/months/years from now — with natural-month carry-over (Jan 31 + 3 months = Apr 30) and holiday countdowns, all computed locally in your browser.
Roman Numeral Converter
Two-way conversion between numbers and Roman numerals (1–3999), with a clickable 1–100 chart, the clock-face IIII, book volume & chapter numbering and copyright-year lines — paste MMXXVI and get 2026 instantly.
Open the Roman Numeral Converter →
Number to Chinese Uppercase
Convert RMB amounts into the uppercase wording required on Chinese checks (yuan, jiao, fen — with 零 and 整 placed per PBOC rules), turn dates into uppercase check dates, and read numbers out in Chinese words, with a live mock-check preview.
Life Path Number Calculator
Enter your Gregorian birthday and get a full numerology chart in real time: life path number with 11/22/33 master-number tagging, a nine-grid energy chart with circles, lines and missing numbers, plus birthday, talent and zodiac numbers.
Open the Life Path Calculator →
Word Counter
Count words and characters at once — Word-style word count, characters with and without spaces, and CJK-aware stats — with limits for common platforms so tweets, meta descriptions and submission requirements line up at a glance.
Case Converter
Uppercase, lowercase, title case and sentence case in one click, plus camelCase, snake_case and kebab-case naming conversions for programmers, with a 26-letter reference table.
URL / Base64 / MD5 Converter
URL encode/decode, Base64 encode/decode and MD5 hash generation on one page: results appear as you type. Component/full-URL modes handle parameters and whole addresses, URL-safe output and 76-char wrapping cover JWT and email scenarios, and Chinese or emoji round-trips exactly in UTF-8 — all locally in your browser.
Open the URL / Base64 / MD5 Converter →
Color Codes
HEX, RGB and HSL conversions with a color picker, gradient and palette builder, CSS named-color lookup, and scene-based swatches including traditional Chinese colors.
Color Blindness Test
Ishihara-style plates generated live in your browser — quick 5-plate screening, a standard 10-plate test and a shape-based kids version, with instant results and a color blindness simulator that shows how protan, deutan and tritan vision sees each plate.
Take the Color Blindness Test →
Kinship Calculator
Tap a family chain like "father's brother's wife" and get the term instantly — plus what they call you, split by your gender, with side/generation tags and everyday nicknames. Covers the full Western kinship system: merged terms (one word for uncle/aunt/cousin), the -in-law suffix, the great- prefix, and first-cousin-once-removed puzzles.
Teleprompter
Paste your script and read it off a full-screen scrolling prompter — speed, font size, line height and text width adjustable live, with a 1:6 live preview, reading line, mirror mode for 45° prompter glass, a green-screen theme for OBS, and an estimated speaking time based on your script's language mix. Script and settings stay in your browser.
Chinese Character Decomposition
Split hanzi into radicals and components: whole-text fun decomposition (gentle/full/partial levels), per-character structure analysis, and one-click restore — all 6,763 GB2312 hanzi covered. Great for teaching radicals or playing the classic split-character word game. Runs locally with no limits.
Open Chinese Character Decomposition →
How we pick tools
Only tools that work without an account and without sending your content to a server make it into this collection — anything that would require a server round trip is excluded on purpose. Each tool page explains exactly what it does and how to get the most out of it.