decimals · negatives · scales to quadrillion

Convert numbers ↔ words

Bidirectional: 1234.56 ⇄ 'one thousand two hundred thirty-four point five six'. Handles integers, decimals, negatives.

Number ⇄ Words
Direction
num→words
mode
Input
7 B
size
Output
51 B
valid
Scale
10^15
max
input · number
output · words
one thousand two hundred thirty-four point five six
Quick Start

How to convert numbers

Splits the integer into 1000-groups, names each group, then appends scale (thousand, million, …). Reverse parses tokens back into a number.

  1. 01

    Pick direction

    Number→Words or Words→Number. Toggle as needed.

    Tokenisation is Unicode-aware via \p{L}\p{N} property classes — so accented letters, ideographs, and emoji code points all count correctly.

    modeUTF-8Unicodecode pointslive
    dir · text→ · UTF-8
    num → words
    loaded · UTF-8UTF-8 · ready
  2. 02

    Type input

    '1234.56' or 'one thousand two hundred…'. Negatives prefixed with -, decimals with a dot.

    Live re-counts run on every keystroke through a memoised reducer, so even multi-megabyte inputs stay smooth in the editor.

    inputlivememoisedoptionssnappy
    src · optionsraw · live
    1234.56
    options applied · livelive
  3. 03

    Live result

    Output updates as you type. Invalid input shows '(cannot parse)'.

    Output preserves the original line endings (\n vs \r\n) and trailing whitespace is reported separately so you can spot diff-only changes.

    liveline endingswhitespacediff-cleanreproducible
    out · countedlive · ready
    one thousand…
    counted · livecounted
  4. 04

    Copy result

    One click to clipboard for use in receipts, contracts, accessibility text.

    Copy writes via the Async Clipboard API; downloads ship as text/plain; charset=utf-8 — nothing leaves your tab.

    copyclipboardtext/plainblobclient-side
    ✓ · copiedready · done
    ✓ Copied
    shipped · ready to shipsuccess
Pro tips

Text-processing fundamentals worth knowing

Tokenise with Unicode classes

Use \p{L}\p{N} with the u flag so accents, ideographs, and emoji count properly.

Normalise line endings

Convert \r\n to \n before diffing or hashing — Windows-vs-Unix endings produce phantom changes.

Mind invisible characters

Zero-width joiners, BOMs, and non-breaking spaces look identical to ASCII space. Strip them before comparison or storage.

Stream don’t slurp

For multi-megabyte text, iterate line-by-line rather than loading everything to memory — keeps the tab responsive.

Choose collation deliberately

Default JS sort is code-point order, not human alphabetical. Use Intl.Collator for locale-aware sorting.

Re-run after normalisation

NFC vs NFD changes byte length but not visible glyphs. String.prototype.normalize() before counts and comparisons.

Use Cases

When to spell numbers

Finance, accessibility, language learning.

Cheques

Spell out the amount on a cheque. Tokenisation uses Unicode property classes (\p{L}, \p{N}) with the u flag so accents, ideographs, and emoji code points all count correctly. Surrogate-pair-aware counts mean 🚀 weighs 1, not 2.

Unicode-correct

Legal documents

Amounts often required in both digits and words. Result updates as you type — paste and watch totals settle in milliseconds even on multi-megabyte inputs. Heavy work runs through a memoised reducer so the editor never janks.

diff-clean

Accessibility

Screen-reader-friendly numeric strings. Output normalises line endings to LF for clean diffs across platforms. Windows-vs-Unix CRLF mismatches disappear, which keeps git blame honest and review comments focused on real changes.

a11y-friendly

ESL teaching

Show students how big numbers read aloud. Code-point counts are stable across NFC/NFD normalisation. Pair with the Reading Time Calculator to layer scan-time on top of raw counts, useful for editorial budgets and SEO meta-description limits.

platform-aware

Form validation

Confirm digit + word amounts agree. All processing runs client-side — paste sensitive or pre-publish copy without it leaving the tab. The clipboard API writes UTF-8 text/plain so it survives transit to any editor or CMS.

code-point-accurate

Voice UI scripts

Pre-format numbers for TTS. Same input plus same options always produces identical output, so the tool is safe to embed in CI scripts or doc-generation pipelines without race conditions.

lossless
FAQ

Frequently asked questions

Quadrillion (10^15). JavaScript number precision starts to break beyond that.
Uses short-scale (American/UK modern): billion = 10^9.
Read digit by digit after 'point': 1.25 = 'one point two five'.
Prefixed with 'negative': -5 = 'negative five'.
No. All conversion runs locally.
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