Is there a difference between NO later than and NOT later than?

Question

Is there a difference between no later than and not later than? -Vikit, Thailand

Answer

Thank you for your question, which was an interesting one to consider. A review of the data on these two time expressions shows the following: 

Both no later than and not later than are used to tell when an event or action will, should, or must be completed, in constructions such as these:

• No/not later than 6pm on a weekday
• No/not later tomorrow afternoon
• No/not later than February 15th
• No/not later than a year after publication

However, there are differences in the way these two expressions are used. No later than is used more often than not later than, and it is less formal. Not later than is used mostly in formal documents, such as rulebooks, government laws, and academic papers. 

Below are some example sentences that illustrate these differences. 

NO later than

1. I’ll be back no later than 6 o’clock.
2. We'll need to know your decision no later than next week. 
3. Cucumbers should be planted no later than August 31st.
4. Republicans say they are going to vote no later than January 6th or 7th.

NOT later than

1. All horses to be entered in the race must have a physical exam not later than 14 days before the race. 
2. In the legislature, a resolution with more than sixty co-sponsors asked the President to withdraw as soon as possible, but not later than October 1st, 2006. 
3. Not later than December 31, 2013, a health plan shall file a statement with the Secretary’s office, certifying that the data and information systems for such plan comply with all standards. 
4. The critical review shall be on a published scientific paper chosen from a list of papers announced by the Chairman of the Faculty of Biology not later than the second Friday of the winter term. 

I hope this helps.

Help with other time-related expressions:

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• Every day or everyday?