There are numerous counting words in Persian, such as جلد jeld ‘volume’ (for books, etc.), رأس ra’s ‘head’ (for animals), دستگاه dastgāh ‘apparatus; machine’ (for machines of any sort, in addition to buildings), and many more.

In colloquial Persian, however, there is the generic counting word تا (originally means ‘one of a pair’), which can replace any of the other counting words. However, while all counting words are used with all numbers, including yek ‘one’, تا is never used with yek.

Examples:

a man	yek mard	یک مرد
two men	dó mard (formal)	دو مرد
	dó tā mard (colloquial)	دو تا مرد
three men	sé mard (formal)	سه مرد
	sé tā mard (colloquial)	سه تا مرد

A counting word as دانه dāne ‘grain’ is used formally only with small particles, such as grains of legumes, etc.; but in colloquial dialect it is used interchangeably with تا as a generic counting word, especially with a single item. As such, unlike تا, دانه (colloquial دونه) is used with یک (colloquial یه) as well:

یه دونه سیب
ye dune sib (colloquial)
‘an apple’

یه دونه گوسفند
ye dune gusfand
‘a sheep’

Usually with more than one item these two generic counting words are combined in the colloquial dialect:

دو تا دونه سیب
do tā dune sib
‘two apples’ (literally, “two single units of apple”).

Numbers are invariably followed by a singular noun: یک کتاب yek ketāb ‘a/one book,’ ده کتاب dah ketāb ‘ten books,’ etc. In other words, the noun کتاب is invariably in singular.

Some of the counting words in Persian are as follows:

Counting Word	Example
تخته taxte board (for carpets, rugs, etc.)	یک تخته فرش yek taxte farš a (single count of) carpet
جلد jeld volume, a bound item (for books, etc.)	سه جلد کتاب sé jeld ketāb three volumes of books
دانه dāne grain (for small items, especially a single one)	یک دانه برنج yek dāne berenj a single grain of rice
دستگاه dastgāh apparatus (for machines of any sort and buildings)	دو دستگاه اتومبیل dó dastgāh otomobil two cars سه دستگاه آپارتمان sé dastgāh āpārtemān three apartments
رأس ras head (for almost all stock animals)	پنج رأس گوسفند panj ras gusfand five (heads of) sheep
فروند farvand (for ships, airplanes and spaceships)	یک فروند هواپیما yek farvand havāpeymā an airplane
قالب qāleb bar, mold (for soap, butter, cheese, etc.)	دو قالب صابون dó qāleb-e sābun two bars of soap
نفر nafar person, individual (for people and camels)	چهار نفر ایتالیایی cahār nafar itāliyāyi four Italians دو نفر می آیند dó nafar mi āyand two individuals come, are coming, will come