ต่อ (อัตรา)

Per

Level 4

ต่อ (tòo) means 'per' in rates, such as speed or daily wages, and 'to' in ratios or scores.

How It Works

Express A Rate
ต่อ connects an amount with the unit it is measured against. In ๘๐ กิโลเมตรต่อชั่วโมง, the amount is 80 kilometers and the unit is an hour. In ๖๐๐ บาทต่อวัน, the amount is 600 baht for a day.

Read Both Sides Of A Ratio
๑ ต่อ ๕ gives a ratio of one to five. สามต่อศูนย์ gives a score of three to zero. These examples use English to rather than per.

Compare The Word Order With ละ
The daily-frequency task practises สามครั้งต่อวัน, three times per day. With ละ, the displayed alternative is วันละสามครั้ง. Read the whole quantity-and-unit phrase before changing its order.

Compare An Amount At A Time
ทีละ introduces one step or batch at a time. A rate or ratio and a sequence answer different questions about the amount. The other meanings of ต่อ should be read in their own complete constructions.

Examples (5)

  1. รถวิ่งด้วยความเร็ว ๘๐ กิโลเมตรต่อชั่วโมง

    The car is traveling at a speed of 80 kilometers per hour.

    Word by Word: Car run with speed 80 kilometer per hour

    กิโลเมตรต่อชั่วโมง states the distance unit against an hour: kilometers per hour.

  2. ผสมน้ำยาในอัตราส่วน ๑ ต่อ ๕

    Mix the solution in a ratio of 1 to 5.

    Word by Word: Mix liquid in ratio 1 to 5

    In this displayed ratio, ต่อ connects 1 and 5 with the reading one to five.

  3. พนักงานได้รับค่าจ้าง ๖๐๐ บาทต่อวัน

    The employee receives a wage of 600 baht per day.

    Word by Word: Staff receive wage 600 baht per day

    ต่อ links the stated wage of 600 baht to one day.

  4. อัตราการเกิดคือเด็ก ๑๐ คนต่อประชากร ๑,๐๐๐ คน

    The birth rate is 10 children per 1,000 population.

    Word by Word: Rate of birth is child 10 person per population 1,000 person

    The example gives 10 children against a population unit of 1,000 people. These are illustrative quantities, not a measured birth-rate report.

  5. คะแนนคือสามต่อศูนย์

    The score is three to zero.

    Word by Word: Score is three to zero

    Used in sports or competitions to indicate the current standing between two sides.

Common Mistakes

  • Using the wrong order for the intended daily rate “three times per day.”

    วันต่อสามครั้ง
    สามครั้งต่อวัน

    For this intended rate, put the frequency before ต่อ and the unit after it: สามครั้งต่อวัน. With ละ, the corresponding pattern is วันละสามครั้ง. This correction concerns that rate phrase rather than every use of ต่อ.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

ต่อ (อัตรา)Level 4Per

Learn This First

To use 'ต่อ' (per) to express rates, you need to be comfortable with Thai numbers and how classifiers function as units of measurement. You also need to understand basic sentence structure to integrate these rate expressions into your speech.

Words in This Pattern

ต่อ