Is “Until” Inclusive or Exclusive?

The word “until” is a little ambiguous because it could have an inclusive or exclusive reference. This depends on how you use it in a sentence. Since “until” refers to a specific period in time, it lends itself to being ambiguous. This completely dependson the situation or discussion at hand.

Therefore, this slight uncertainty means there are no hard and fast rules to remember which is which. But, it’s important to understand the nuance of difference.

“Until” as Inclusive

When the indicated time range is clear, “until” is inclusive. This usually happens when talking about a business or other organization and its operating hours. The ambiguity in this way is more specific.

The clothing boutique is open Sunday until Saturday.

We will be at the doctor’s office from 8 a.m. until 2 p.m.

She swims every day from noon until night.

“Until” as Exclusive

For an exclusive use of “until,” it is a separate time period from others. You will see this used far more than “until” as an inclusive reference. This can refer to recipes, schedules, or discussing a moment that must occur before something else can happen.

Bake in the oven on 250°F until there is no visible pink.

Until he returns with the car, we can’t go anywhere.

She’s always out of the office from Thursday night until Friday morning.

I will be on vacation until next Thursday.

He will stay at his desk until the last security guard goes home.

The Distinctions; Ambiguity of “Until”

When the ambiguity of “until” is confusing or not obvious at the outset, it’s better to be as particular about the time as possible. But, this is only when “until” is incomprehensible within its context and it’s not clear.

  • Ambiguous: She swims every day from noon until night.
  • Specific: She swims every day from starting at 1 p.m. until 7 p.m.
  • Ambiguous: I will be on vacation until next Thursday.
  • Specific: I will be on vacation until Thursday and will arrive home at 3 p.m.


“Until” can be inclusive or exclusive depending on the context. It indicates an ambiguous reference to time. Most inclusive references are often in conjunction with the operating hours of a business. However, much of “until” references time set off and separate from others, making it exclusive.