thai_number_words 1.0.0

Thai number-to-words utilities: baht text, integers, decimals, fractions, digit-by-digit, Thai/Arabic numerals, and Roman numerals.

Thai Number Words

Lightweight, pure-Dart utilities to convert numbers to Thai words: integers, currency (Baht text), decimals, fractions, digit-by-digit reading, Thai numerals (๐–๙), and Roman numerals. Works on all platforms supported by Dart (iOS, Android, Web, Windows, macOS, Linux) and is WASM-friendly.

This package provides easy-to-use utilities for converting numbers to Thai text, with customizable options.

Features

• Convert integers to Thai words (supports BigInt and negatives)
• Convert to "Baht text" with half-up rounding to 2 decimals (customizable units)
• Read decimals as "point + digit-by-digit" with options for fixed fraction digits
• Handle fractions in the format "X ส่วน Y"
• Easily customize words and reading formats

Quick start

Add the package with dart pub add thai_number_words (or flutter pub add thai_number_words in a Flutter project), or add it to pubspec.yaml:

dependencies:
  thai_number_words: ^1.0.0

Then copy this into a Dart file:

import 'package:thai_number_words/thai_number_words.dart';

void main() {
  print(thaiIntToWords(121)); // หนึ่งร้อยยี่สิบเอ็ด
  print(thaiBahtText(1.1));  // หนึ่งบาทสิบสตางค์
}

The legacy package:thai_number_words/numeric_to_words.dart import remains available. Run the full example with dart run example/main.dart from this repository.

Choose a function

Need	Use
Integer, including BigInt	thaiIntToWords or thaiNumberToWords
Amount in baht	thaiBahtText
Other currencies	thaiCurrencyText or englishCurrencyText with CurrencyRegistry
Decimal read digit by digit after the point	thaiDecimal
Fraction	thaiFraction
ID, OTP, or other digits with leading zeroes	thaiDigits (pass a String)
Thai or Roman numerals	parseThaiInteger, arabicDigitsToThai, thaiNumeralsToArabic, parseRoman, or romanToThaiWords

Examples (Quick Start)

See the full runnable example in example/.

Integers:

thaiIntToWords(121); // "หนึ่งร้อยยี่สิบเอ็ด"
thaiIntToWords(2523456); // "สองล้านห้าแสนสองหมื่นสามพันสี่ร้อยห้าสิบหก"
thaiIntToWords(-1); // "ลบหนึ่ง"

Currency (Baht text):

thaiBahtText(0); // "ศูนย์บาทถ้วน"
thaiBahtText(1.1); // "หนึ่งบาทสิบสตางค์"
thaiBahtText(1.005); // "หนึ่งบาทหนึ่งสตางค์" (half-up rounding)
thaiBahtText(-12.3); // "ลบสิบสองบาทสามสิบสตางค์"
thaiBahtText('1,234.56'); // "หนึ่งพันสองร้อยสามสิบสี่บาทห้าสิบหกสตางค์"

// Customize units
thaiBahtText(
	10.5,
	options: const ThaiBahtTextOptions(majorUnit: 'ดอลลาร์', minorUnit: 'เซนต์'),
); // "สิบดอลลาร์ห้าสิบเซนต์"

// Omit 'ถ้วน' for integer baht
thaiBahtText(100, options: const ThaiBahtTextOptions(useIntegerSuffix: false)); // "หนึ่งร้อยบาท"

Pass a decimal String for exact monetary input; existing num calls continue to work.

Currency (English/Thai words):

Use the built-in registry for currency names and format in English or Thai.

// English words
final usd = CurrencyRegistry.byCode['USD']!;
englishCurrencyText(25, usd); // "twenty-five dollars"
englishCurrencyText(1.05, usd); // "one dollar and five cents"

// Thai words for non-THB currency (uses a space between number and unit)
thaiCurrencyText(25, usd); // "ยี่สิบห้า ดอลลาร์สหรัฐ"

// Currencies without minor units example (JPY)
final jpy = CurrencyRegistry.byCode['JPY']!;
englishCurrencyText(1250, jpy); // "one thousand two hundred fifty yen"
thaiCurrencyText(1250, jpy); // "หนึ่งพันสองร้อยห้าสิบ เยน"
englishCurrencyText(1.5, jpy); // "two yen" (JPY has no minor unit)

final kwd = CurrencyRegistry.byCode['KWD']!;
englishCurrencyText('1.2345', kwd); // "one dinar and two hundred thirty-five fils"

Both currency formatters also accept decimal String values for exact monetary input.

Decimals:

thaiDecimal(0.5); // "ศูนย์จุดห้า"
thaiDecimal(1.0); // "หนึ่ง" (by default omits trailing .0)
thaiDecimal(1.0, options: const ThaiDecimalOptions(omitPointWhenFractionZero: false));
// => "หนึ่งจุดศูนย์"
thaiDecimal(0.5, options: const ThaiDecimalOptions(fixedFractionDigits: 2));
// => "ศูนย์จุดห้าศูนย์"

Fractions:

thaiFraction(BigInt.one, BigInt.two); // "หนึ่งส่วนสอง"
thaiFraction(BigInt.from(3), BigInt.from(4)); // "สามส่วนสี่"
thaiFraction(BigInt.from(-1), BigInt.from(2)); // "ลบหนึ่งส่วนสอง"

Digit-by-digit (OTP/IDs):

thaiDigits('12345'); // "หนึ่งสองสามสี่ห้า"
thaiDigits('-007'); // "ลบศูนย์ศูนย์เจ็ด"
thaiDigits('12.30', options: const ThaiDigitsOptions(includeDecimalPoint: true, separator: ' '));
// => "หนึ่ง สอง จุด สาม ศูนย์"

Roman numerals:

parseRoman('IV'); // 4
parseRoman('LXXX'); // 80
parseRoman('MMDCCCLXII'); // 2862
parseRoman('CM'); // 900
romanToThaiWords('IV'); // "สี่"

Overline note: Combining overline (U+0305) multiplies a symbol by 1,000. For example, M̅ = 1,000,000 (write M\u0305 in Dart).

parseRoman('M\u0305'); // 1000000
romanToThaiWords('M\u0305'); // "หนึ่งล้าน"

Thai numerals utilities:

Convert between Arabic and Thai digits, and parse Thai digits to numbers.

arabicDigitsToThai('123'); // "๑๒๓"
thaiNumeralsToArabic('๑๒๓'); // "123"
parseThaiInteger('๑๒๓'); // BigInt(123)

Quick table: Roman ↔ Arabic ↔ Thai words

Roman	Arabic	Thai words
I	1	หนึ่ง
IV	4	สี่
V	5	ห้า
IX	9	เก้า
X	10	สิบ
XL	40	สี่สิบ
L	50	ห้าสิบ
XC	90	เก้าสิบ
C	100	หนึ่งร้อย
D	500	ห้าร้อย
M	1000	หนึ่งพัน
M̅	1,000,000	หนึ่งล้าน

Summary: integers vs decimals/fractions

Number	Integers	Decimals/Fractions
1.0	หนึ่ง	หนึ่ง (or "หนึ่งจุดศูนย์" with omitPointWhenFractionZero: false)
0.5	–	ศูนย์จุดห้า (or "ศูนย์จุดห้าศูนย์" when fixedFractionDigits: 2)
1/2	–	หนึ่งส่วนสอง
3/4	–	สามส่วนสี่

Options

// Customize negative and zero words
const numOpts = ThaiNumberOptions(negativeWord: 'ติดลบ', zeroWord: 'ศูนย์');

// Customize currency units and suffix
const bahtOpts = ThaiBahtTextOptions(
	majorUnit: 'บาท',
	integerSuffix: 'ถ้วน',
	useIntegerSuffix: true, // set to false to omit 'ถ้วน'
);

// Customize decimal reading
const decOpts = ThaiDecimalOptions(
	decimalPointWord: 'จุด',
	omitPointWhenFractionZero: true,
);

// Digit-by-digit reading (e.g., OTP)
const digitOpts = ThaiDigitsOptions(
	separator: ' ',
	decimalPointWord: 'จุด',
);

Compatibility

• Requires Dart ^3.8.1 (including compatible Flutter versions).
• No external runtime dependencies.

Tips & Best Practices

• Prefer const options for reuse; use BigInt with thaiNumberToWords for very large integers.
• Currency rounding is half-up to 2 decimal places; pass a decimal String when exact input matters.

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Thai readers: อ่านเอกสารภาษาไทย