ตั้งแต่

ตั้งแต่ marks when an action began or where a range starts.

1. Temporal Usage (Since)
When used to mean 'since,' it attaches directly to a time noun or phrase. It can refer to the past or the future (e.g., 'starting from tomorrow'). When referring to future starting points, one useful phrase is ตั้งแต่ + [Future Time] + เป็นต้นไป (from [time] onwards). For past starting points continuing to the present, the counterpart ตั้งแต่... เป็นต้นมา (from [past time] up to now / since then) describes a period beginning at that past point and extending toward the present. In sentences describing an action that started in the past and continues to the present, you can add the continuative marker มา after the verb phrase (e.g., Verb + Object + มา) to show continuation toward the present. It can also attach directly to life stages without needing the word for 'time' or 'age' (e.g., ตั้งแต่เด็ก - since childhood, ตั้งแต่เกิด - since birth). In everyday spoken Thai, ตั้งแต่ can appear as แต่ when attached to time words or life stages (e.g., แต่เช้า - since morning, แต่เด็ก - since childhood). To ask 'since when?', one question form is ตั้งแต่เมื่อไหร่ (combining it with เมื่อไหร่). Another written form is นับตั้งแต่ (counting from). Additionally, ตั้งแต่ can carry the nuance of 'as early as' to show surprise at how early something started (e.g., 'He woke up as early as 5 AM').

2. As a Conjunction
ตั้งแต่ can link two clauses together to show that a situation has been true since a specific event occurred (e.g., 'Since I started this job...'). When placed before a full clause (Subject + Verb), you can add the clause-linking word ที่, forming the structure ตั้งแต่ที่....

3. Range Usage (From... to...)
A range can use the structure ตั้งแต่... ถึง.... Other endpoint expressions include จนถึง or จนกระทั่ง as alternatives to ถึง. In everyday spoken Thai, the colloquial word ยัน can name an endpoint (e.g., ตั้งแต่เช้ายันเย็น - from morning till evening). This applies to:

• Time: From 9 AM to 5 PM.
• Items: Everything from pens to paper.
• Space: From the front to the back.

4. Distinction from จาก
Compare ตั้งแต่ with จาก. While จาก simply marks a starting point and can be used for both time (e.g., จาก 9 โมง ถึง 5 โมง) and physical movement (e.g., เดินทางจากกรุงเทพ - travel from Bangkok), when it describes a duration, ตั้งแต่ highlights its starting point and the span that follows. For a physical extent, ตั้งแต่ can mark its starting point (e.g., รถติดตั้งแต่สี่แยก - traffic is backed up from the intersection), while จาก can mark the origin of movement or travel.