につきPer unit

Marks the unit used to calculate a rate, fee, limit, measurement, or allocation. It corresponds to “per,” “for each,” or “for every.”

Identify the base unit

The expression before につき is the unit used as the base of the calculation. The rest of the sentence gives the price, quantity, limit, or measurement corresponding to that unit. A clear sentence therefore lets the reader recover both sides of the rate.

Fees, limits, and measurements

入にゅう場じょう料りょうは一人ひとりにつき千せん円えんです。

Admission is 1,000 yen per person.

Analyze

このクーポンは一いっ回かいの会かい計けいにつき一いち枚まいまで使し用ようできます。

You may use up to one of these coupons per transaction.

Analyze

このポンプは一いち時じ間かんにつき約やく二に十じゅうリットルの水みずを処しょ理りします。

This pump processes approximately twenty liters of water per hour.

Analyze

In a formal rule

申しん請せいは一いっ世せ帯たいにつき一いっ件けんまでとします。

Applications are limited to one per household.

Analyze

Here the household is the unit, and one application is the permitted maximum for that unit.

Three forms that can look similar

につき can also have a separate formal meaning, “due to,” when it follows a reason rather than a unit. Ask whether the noun provides a base for calculating an amount; if not, it is not the per-unit use taught here. 当あたり also expresses a per-unit rate and is particularly common in compact statistical and average expressions. ずつ instead emphasizes equal shares, equal batches, or repeated increments: it describes how quantities are actually distributed rather than simply naming the base of a rate.