Unless and If Often when we are talking about present situations, we use unless instead of if...not . Unless means except if or simply it means if...not . Both of these examples have the same meaning and refer to the present time. "You can't go on vacation unless you save some money." " If you don't save some money, you can't go on vacation." "You will feel cold if you don't wear a coat." "You will feel cold unless you wear a coat." Unless is good to use when it highlights an exception to what is generally true. In this example I only have one reason why I may be late: traffic (vehicles on the road): "I'll arrive at 10am unless there is traffic." "I'll arrive at 10am if there isn't traffic." This next example shows us that sometimes the context can change and unless is not exactly interchangeable with if...not . "I'll be annoyed if I do not arrive at 1