Number DigitHow to write numbers in Spanish
This converter spells out a number using Spanish cardinal words. Enter your value, check the separator format, and choose whether you need the standalone number or a form used before a noun. The interpreted value appears next to the result so you can confirm the quantity before copying it. The interface and explanations are in English; the converted words are in Spanish.
One word or several words?
The usual spellings from zero through twenty-nine are single words. Some need written accents, including dieciséis, veintidós, veintitrés and veintiséis. From thirty onward, tens and units are joined with y, as in treinta y cuatro. An exact ten such as cuarenta does not need this conjunction. It is not inserted between every group: 234 is doscientos treinta y cuatro.
When to use cien or ciento
Exactly 100 is cien. When the hundred has a remainder, use ciento, as in ciento cinco. The hundreds also include irregular forms worth recognizing: quinientos, setecientos and novecientos. One thousand is simply mil. For 1001, the unit follows the thousands group: mil uno. Internal zero digits preserve place value without being read individually in a whole number.
Choosing uno, un or una
The standalone number 21 is veintiuno. Before a masculine noun such as libros, use veintiún; before a feminine noun such as casas, use veintiuna. Hundreds can also agree in gender: compare doscientos libros with doscientas casas. The tool returns the numeral only, without adding a noun. Feminine nouns beginning with a stressed a sound, such as águila, have additional rules outside the feminine mode provided here.
Millions and the Spanish long scale
The converter uses the Spanish long scale. Un millón means 1,000,000, while un billón means 1,000,000,000,000. Consequently, one English billion is mil millones. Do not replace the English word billion with the similar-looking Spanish word billón without checking the quantity. The scale nouns millón and billón are masculine, including when the overall quantity refers to a feminine noun.
Reading decimals without losing digits
Decimal digits are read one at a time. This preserves leading and trailing zeros after the separator: 12,05 becomes doce coma cero cinco with decimal-comma input. Select decimal-point input for values such as 12.05; that format uses punto in the reading. The converter preserves up to twelve decimal digits without rounding. To avoid ambiguity, enter the whole-number part without grouping separators or use spaces in groups of three.
This tool produces cardinal words, not ordinal positions or complete currency expressions. Writing positions, fractions, or amounts with currency units requires additional rules. Always check the interpreted quantity and selected grammatical form before using the result in a document.