ASCII / Unicode Codepoint Lookup Calculator
Enter a single character (emoji, CJK, anything) or a Unicode codepoint (`U+9999`, `0x9999`, `\u9999`, `香`, decimal `39321`); the tool returns the *Unicode codepoint*, *UTF-8 byte sequence*, *UTF-16 code units (with surrogate pair where applicable)*, *HTML numeric entities (&#dec; / &#xhex;)*, *JavaScript / TypeScript string escape*, and classifies the codepoint into its Unicode plane (BMP / SMP / SIP / ASCII control) — useful for debugging character encoding, emoji handling, CJK multi-byte text and invisible control characters.
Invalid input — accepts a single character, `U+9999`, `0x9999`, `\u9999`, `香`, or a decimal codepoint of two-plus digits (e.g. `65`).
Character
香
BMP — Basic Multilingual Plane
Notes
- **Accepted input**: (1) a single Unicode character — `A`, `香`, `🌏` (including emoji and CJK); (2) a hex codepoint — `U+9999`, `0x9999`, `\u9999`, `香`; (3) a decimal codepoint of two or more digits — `65`, `39321`, `香`. A single digit is treated as the character (e.g. `0` → the digit "0", not the NUL control). To look up U+0000, type `U+0000`.
- **UTF-8 / UTF-16 results**: UTF-8 encodes any codepoint in 1–4 bytes; UTF-16 stores BMP codepoints (U+0000–U+FFFF) in a single code unit and uses a *surrogate pair* (one 0xD800–0xDBFF and one 0xDC00–0xDFFF code unit) for everything else. JavaScript strings are UTF-16, which is why an emoji like 🌏 (U+1F30F) has `.length` 2, not 1.
- **Lone surrogates rejected**: the range U+D800–U+DFFF is reserved for *surrogate code points* — they have no character meaning on their own and only exist to pair up and encode supplementary-plane codepoints in UTF-16. The tool refuses to look those up.
Formula
Parse input → Unicode codepoint cp (0 … 0x10FFFF, lone surrogates U+D800–U+DFFF rejected) UTF-8 encoding: cp ≤ 0x7F: 1 byte = cp cp ≤ 0x7FF: 2 bytes = 11000xxx 10xxxxxx cp ≤ 0xFFFF: 3 bytes = 1110xxxx 10xxxxxx 10xxxxxx cp ≤ 0x10FFFF:4 bytes = 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx UTF-16 encoding: cp ≤ 0xFFFF: 1 code unit = cp cp ≥ 0x10000: surrogate pair high = 0xD800 + ((cp − 0x10000) >> 10) low = 0xDC00 + ((cp − 0x10000) & 0x3FF)
- · **Unicode structure**: Unicode partitions code points into 17 *planes* (0–16), each holding 65,536 code points, for a total of 1,114,112. The everyday *BMP* (U+0000–U+FFFF) covers Latin, CJK ideographs, Greek, and most major writing systems; the *SMP* (U+10000–U+1FFFF) carries emoji and historic scripts (oracle bone, cuneiform); the *SIP* (U+20000–U+2FFFF) carries rare CJK ideographs.
- · **JavaScript strings are UTF-16**: so `"🌏".length === 2` (a surrogate pair). To count *characters*, iterate code points with `[...str].length` or `Array.from(str).length`.
- · **Lone surrogates rejected**: U+D800–U+DFFF are *pair-only* UTF-16 code points and do not encode any real character. Strict UTF-8 encoders throw when given a lone surrogate like `"\uD800"`.
- · **ASCII control characters**: U+0000–U+001F and U+007F are *control codes* — NUL, BEL, BS, TAB, LF, CR, ESC, DEL etc. — usually invisible in a UI. This tool shows them as a `[U+00XX]` placeholder.
- · **HTML entity format**: `香` and `香` are equivalent in modern (HTML5) browsers and render as `香` directly inside a document. You can technically drop the trailing `;` — `香A` renders as `香A` — but don't.
- · **JS / TS string escapes**: BMP characters use `\u9999` (four hex digits); SMP+ uses `\u{1F30F}` (ES2015+). Older environments require the explicit surrogate pair `\uD83C\uDF0F`.
Frequently asked
Why is `"🌏".length` 2 instead of 1?
**Because JavaScript strings are UTF-16.** `String.prototype.length` returns the number of *UTF-16 code units*, not characters. The code point U+1F30F is outside the BMP (U+0000–U+FFFF), so UTF-16 uses a *surrogate pair* — `0xD83C 0xDF0F` — and length is 2. **Counting properly**: ```js Array.from("🌏").length // 1 [..."🌏"].length // 1 new Intl.Segmenter().segment("🌏") // 1 grapheme ``` **One more layer — graphemes**: an emoji like 👨👩👧👦 (family) is *4 emoji + 3 ZWJ* glued into *1 visible grapheme*. That is 7 code points, 11 UTF-16 units, but 1 grapheme. For a "character count" the user sees, use `Intl.Segmenter`.
Codepoint, UTF-8, UTF-16, UCS-2 — what's the difference?
**Code point** = Unicode's *unique number* for each character, U+0000 to U+10FFFF. `U+9999` is the abstract identity of 香 — it says nothing about how it is laid out in bytes. **Encodings** (codepoint → bytes): • **UTF-8**: variable length, 1–4 bytes. ASCII-compatible (1 byte for U+0000–U+007F), CJK takes 3 bytes, emoji take 4. The web, Linux and macOS default. • **UTF-16**: variable length, 2 or 4 bytes (1 or 2 code units). BMP fits in one unit; SMP+ uses a surrogate pair. The Windows / Java / JavaScript default. • **UCS-2**: *fixed* 2 bytes — "UTF-16 before surrogates were defined". Obsolete; lingers in legacy Windows APIs and SQL Server `NCHAR`. • **UTF-32**: fixed 4 bytes. Simple but wasteful; mostly used in-memory. **Rule of thumb**: use UTF-8 for files and over the wire; UTF-16 (JS / Java) or UTF-32 (Python internal) is fine for in-memory.
I inserted `香` into the database but I get back `香` — why?
**Almost certainly the side-effect of HTML escaping.** `香` is the *HTML numeric entity* for U+9999 = 香 — it's how HTML represents the *text* `香`. If your DB hands back that entity-encoded form, the row was *escaped before insertion*. **Typical causes**: 1. *Template-layer auto-escape* (PHP `htmlspecialchars`, Django without `|safe`, Rails `h()`) ran on the request body and stored the escaped form. 2. *Legacy DB charset* (latin1, Windows-1252) cannot hold U+9999, and the framework silently fell back to HTML-escaping non-ASCII. 3. *Hand-rolled "SQL-injection prevention"* that escapes everything non-ASCII to numeric entities. **Fixes**: 1. Migrate the column to `utf8mb4` (MySQL) or `UTF8` (Postgres). 2. Explicitly set `charset=utf8mb4` (or `client_encoding=UTF8`) on the connection. 3. Move HTML-escaping *to render time*, not storage time.
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Enter an incandescent bulb wattage (e.g. 60 W); using Energy Star's lumens-per-watt standards, the tool returns the equivalent LED watts, CFL watts and total lumens — useful when swapping out old bulbs.
Fresh ↔ Dried Herb Substitution Calculator
Enter fresh herb quantity (tsp / Tbsp / cup); using the industry 3 : 1 fresh-to-dried substitution rule, returns the dried equivalent. Reverses, includes 12 common herb defaults, and accepts a custom ratio.
Salt Volume Conversion (Kosher / Table / Sea) Calculator
Enter the recipe salt amount (tsp / tbsp / g / oz) and source type; the tool returns the equivalent volume in Diamond Crystal, Morton, table, sea and Maldon salt using Serious Eats / Cook's Illustrated bench-tested densities.
Climbing Grade Conversion Calculator (YDS / French / UIAA / V-scale / Font)
Enter a route or boulder grade in any one system; using the IFSC / UIAA / REI conversion table, simultaneously shows the equivalent in the other four common climbing grade systems.
Audio File Size (Bitrate × Duration) Calculator
Enter audio bitrate (kbps / Mbps) and duration (h / m / s); returns the resulting MP3 / AAC / WAV / FLAC file size in MB / GB, with common podcast and music encoding presets for quick reference.
Time Format Converter (Seconds ↔ HH:MM:SS)
Convert between seconds, minutes, hours and HH:MM:SS form — useful for video editing, sports timing and meeting durations.
Vertical Speed Unit Converter (m/s ↔ ft/min ↔ km/h ↔ knots)
Convert between m/s, ft/min, km/h, knots and ft/s — the five vertical-speed units used in aviation instruments, mountaineering and dive ascent-rate guidance.
Butter Unit Converter (Sticks / Grams / Tablespoons / Cups)
Baking butter conversions: enter any one quantity (sticks, grams, tablespoons or cups) and the tool returns the equivalent in the other three units.
Candy / Sugar Stage Temperature Reference Calculator
Enter syrup temperature (°C or °F) to instantly see the candy stage (thread / soft ball / firm ball / hard ball / soft crack / hard crack / light caramel / dark caramel), its full range and typical dessert use.
LED Display Pixel Pitch & Optimal Viewing Distance Calculator
Enter the LED panel pixel pitch (P-value, e.g. P2.5 / P4) plus screen width × height — get the effective resolution, pixel density and the minimum / comfortable / visual-fusion viewing distances so you size the right panel for any AV install.
Pixels Per Degree (PPD) VR / Display Calculator
Enter the horizontal / vertical pixel count and the corresponding field of view (FOV) — get the pixels-per-degree (PPD), the industry-standard metric for comparing VR headsets, monitors and TVs against the retinal-resolution benchmark (~60 PPD).
CSS Aspect Ratio Padding Calculator
Enter an aspect ratio (e.g. 16:9 or 16/9) — instantly get the padding-bottom percentage and matching CSS snippet (plus the modern aspect-ratio property), for responsive video / iframe containers.
RGB ↔ CMYK Color Converter
Enter RGB (0–255) and instantly get the CMYK percentage values (K, C, M, Y), with matching hex code and printing-friendly tips on the screen-sRGB → CMYK gamut gap.