How is the word "effective" or "effect" used to indicate from which date a new rule / change will be applied? I am not sure which of the following is correct:

These changes will take effect from March 1, 2012.
These changes will take effect on March 1, 2012.
These changes will be effective on March 1, 2012.
These changes will be effective from March 1, 2012.
These changes will be effective March 1, 2012.

Update: I just came across a new phrase:

March 1, 2012 is when the new changes will come into effect.


Hmm, I'd say #2 - #5 are all good and valid, while #1 is rarely used. If you say "take effect from" people would normally expect you to say "through" and give an end date. But for reasons that I don't think have anything to do with grammar, just convention, "be effective from" without an end date is common.

"... be effective on ..." is ambiguous. It could mean only that one day, or it could mean from that day until the indefinite future. People would probably guess from the context. Like if you said, "The new safety regulations will be effective on March 1", people would assume you meant from that day forward. But if you said, "The sale price will be effective on March 1", they'd probably think you meant just for that one day. "... be effective from ..." always means to the indefinite future.

Others have said that "be effective" can also mean "adequate to the purpose". True, but that would be an unlikely meaning when given with a date. If you said, "The new safety regulations will be effective", that would mean that they will, in fact, improve safety. But "The new safety regulations will be effection on March 1" means that's the day they start. I suppose you could imagine a casee where it's truly ambiguous. Like if someone is trying to say that the new safety regulations will be impractical when we install the new machine we're getting on April 1, I suppose he could say, "The new safety regulations will be effection in March", meaning they will be useful in March but will cease to be useful in April. But you could say that sort of thing about all sorts of words and phrases: they could have different meanings in different contexts. Lots of jokes are based on such potential confusion. As well as lots of unnecessary arguments, I suppose.


All are correct, but take effect is preferred to be effective. Take effect on seems most common:

"Changes will take effect on" also has more Google results than the other phrasings.

  • Agreed in general, but this NGram strongly suggests "are effective from" became more prevalent than "will take effect on" a couple of decades ago. Jan 27 '12 at 17:09

I think the first four are all correct. I'd tend to use the 'take effect' versions to avoid possible confusion with the sense of 'effective' meaning 'adequate for the purpose'. The final one feels to me to be an informal shorthand - you'd hear it used but it may not be 100% strictly correct.


I would agree that the first 4 are all valid. There is, however, a difference between "effective from" and "effective on" ( and the take effect equivalents ).

If a change is effective "on" a date, a possible implication is that after then, it will not be taking effect - that is, it is a one-off change just for that day. If it is ongoing - which is more likely - then effective "from" is probably better, although the difference is slight.

I would also consider that "take effect" sounds more like some physical or practical change, whereas "effective" implies a change in regulations. So an increase in the number of traffic warders might "take effect from tomorrow", whereas an increase in ther parking charge could be "effective from next week".

However, the differences are very subtle.

  • 2
    -1: I don't believe "These changes will be effective on Jan 1st 2013" would normally be understood to mean they only apply on that day. If that was the intended meaning you would need to explicitly say so. It's not an implication as such - just that if you were going to qualify the statement with "for that day only", you'd have to use "on" rather than "from". Jan 27 '12 at 15:03
  • I would not use "from", but the others all seem OK. To me "from" sounds like what you get translating in your head from some other language.
    – GEdgar
    Jan 27 '12 at 16:29
  • @FumbleFingers I said it was subtle. So there is a slight suggestion that this could be read that way. I think that gives some reason for using one over the other, but not making the others wrong. Jan 27 '12 at 16:46
  • I agree that in general if something happens on [date] it only happens on that date, and if it happens from [date] it starts happening then, but continues to happen on all following dates. But if the "something happening" is in fact "becoming effective", I think the on/from distinction ceases to have any significance - things which "become effective" or "come into effect" are assumed to continue doing so unless explicitly stated otherwise. Jan 27 '12 at 17:04

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