Numerals

Zero to ten

शून्य (śūnya, "void"): this word, and the placeholder it names, is India's own contribution to mathematics, the idea of zero as a number in its own right.

Eleven to nineteen

Digit + दश (daśa, "ten"), joined by regular sandhi. The exception is 16: षष् + दश would become "ṣaḍdaśa", but the actual word, षोडश (ṣoḍaśa), is an older irregular form that never followed the pattern. 19 also has a common alternative, एकोनविंशति (ekonaviṃśati, "one less than twenty"), which uses the same subtractive logic you will see in the tens below.

The tens

Each ten has its own word; it is not a compound of its digit. The words fall into two groups by ending: -ति/-ti (viṃśati, ṣaṣṭi, saptati, aśīti, navati) and -त्/-t (triṃśat, catvāriṃśat, pañcāśat). Both are feminine nouns and decline like ordinary nouns with those endings, not like the digits.

Building 21–99

Sanskrit doesn't have 78 separate words for 21–99. Almost all of them are the unit digit joined onto its ten by one of two rules:

The digits take a special prefix form in these compounds. A few differ from their standalone form above:

9 also has its own prefix (nava-), so navaviṃśati (29) is valid alongside ekonatriṃśat. But ekona-, "one less than", is the more common form for every 9. Watch for it: it replaces the word for "nine".

Beyond a hundred

Hundreds and thousands compound the same additive way as the tens: digit prefix + शत (śata) or + सहस्र (sahasra, "thousand"):

600–900 and 2,000–9,000 follow the same pattern (ṣaṭśata, saptaśata… dvisahasra, trisahasra…). They aren't spelled out here because it is the same rule again, with शत swapped for सहस्र. The चतुः- (catuḥ-) in 400 is visarga sandhi from चतुर् (catur-) before a voiceless consonant, the same sandhi pattern the chant pages use.

Large numbers

Past a thousand, Sanskrit has a single word for each step up the decimal ladder. This is the classical sequence, the same in Vedic and later texts:

लक्ष (lakṣa, "lakh") and कोटि (koṭi, "crore") are still everyday units in South Asia. निर्युत (niyuta) is sometimes swapped with प्रयुत (prayuta) for 10⁶; sources disagree on the order. Beyond शङ्ख (10¹³), the Vedic, Puranic and later Buddhist texts (such as the Lalitavistāra) each give their own names for larger powers of ten, and the names don't agree. This page stops where the sources still agree.

How the numbers themselves decline

Numbers aren't fixed labels in Sanskrit. The small ones agree with the noun they count, like adjectives, in gender and case:

From 5 (पञ्च) through 19 there is a single plural form that doesn't change with gender: only the case changes, and the same word serves masculine, feminine and neuter. The tens (20–100) are feminine singular nouns, a collective like "a twenty" or "a hundred", not a counting word. The thing being counted usually goes into the genitive plural beside them.