Time is a noun with a number of meanings. In some senses it is countable, and in others it is uncountable. A good learner’s dictionary will give you its many meanings and tell you whether it is countable or uncountable.
Time: seconds, minutes, hours, years
We use time to refer to what is measured in seconds, minutes, hours and years as a whole. In this sense it is uncountable:
How much time do we have for this project?
Children nowadays spend more time watching TV than playing.
Not: … spend more times …
In some expressions time is countable:
At a time in our history when technology is developing so fast, we can’t afford not to invest in Information Technology.
I haven’t seen Brian for a long time.
Time: talking about clock or calendar time
When we talk about specific clock times, time is countable. We do not say hour:
What time is it now?
Not: What hour is it?
Is this a bad time to phone?
Is the swimming pool open at that time?
Not: … at that hour?
We use in …’s time to say when something will happen:
I’ll be finished college in three months’time.
I’ve ordered a new computer and it’ll be here in a week’stime.
We use on time to talk about timetabled events. If something is on time, it means that it is at the scheduled time. We often use right on time or, more informally, deadon time or bang on time, for emphasis:
The trains are usually on time. (They arrive at the scheduled times, not early or late.)
It’s quarter to two. We’d better get back for the meeting.
Don’t worry. These meetings never starton time.
I was lucky. The flight to Chicago arrived right on time, so I got my connection.
We use in time to say we are not late and have enough time to do something. We use it with for plus a noun, or with a verb in the to-infinitive form:
If we leave here at about ten, we should arrive at the coast in time for lunch.
I hope to be there in time to see you before lunch. (early enough to have time to see you before lunch)
We often use the phrase just in time to emphasise that we have time to do something but are almost too late:
You’re just in time for lunch!
The stadium must be completed ontime.
The stadium must be completed intime for the Olympics.
It must be completed according to the schedule.
It must be completed with time to spare before the start of the Olympics.