Is a check without cents in the spelling line valid?

I routinely write “something dollars” without adding the “And 00/100 cents”, and never had a problem.

It’s unambiguous.

It's up to the bank. I usually write them that way and almost never have an issue. However, the bank one time refused to accept one as written (because it was not clear how much it was supposed to be, supposedly) and I had to write a new check. As long as the amount specified is clear and unambiguous, and consistent between the numerical and written lines, you should be OK.

The basic criterion is that a forger can not change the amount by adding to what is already written.

So if someone (including an unscrupulous bank employee!) could change "four hundred and fifty" to "four hundred and fifty thousand" the check should be declared invalid.

FWIW in the UK, the convention was to write "only" after an amount in pounds, e.g. "four hundred and fifty only". (I say "was", since hardly anyone writes checks in the UK these days).

Valid, as in "legal"?

Yes. Section 3-114 of the Uniform Commercial Code (UCC) doesn't specify the format, but does specify how the check is to be interpreted in the case of contradictory content.

If an instrument contains contradictory terms, typewritten terms prevail over printed terms, handwritten terms prevail over both, and words prevail over numbers.

Your example doesn't include contradictory content, but as we'll see later, this comes into play if someone takes the opportunity to alter the check to take advantage of the way you have filled it out.

I haven't found any part of the UCC that requires the presence of the cents portion of an amount in any context. Lacking specific regulations, the law often asks "How would an ordinary, reasonable person see this?" And in this case, Four Hundred and Fifty in your handwriting, plus Dollars at the end, seems pretty clear as to the intent.

Valid, as in "accepted by the bank"?

Highly probable. As yoozer8 points out, it depends on the bank. Most banks will accept a check like you describe, as long as the meaning is obvious. In your case, you have a combination of Four Hundred and Fifty written by hand, plus the word Dollars presumably pre-printed at the end of the line. That combines to make it unambiguous.

Valid, as in "a good idea"?

No. As alephzero points out, leaving it incomplete opens you to the possibility of someone altering the check to make it for more than your intended amount. It depends on the wording of the amount of the original, but adding thousand would make most any amount into an alternate, larger, and still grammatical, amount. As others have mentioned, your best approach to prevent/minimize this risk is to fully specify the amount, including the cents, even if zero, or to otherwise fill out the remainder of the line to make it clear that the amount is what you have entered, and nothing more. Each of these should provide reasonable protection against such an alteration:

• Four Hundred Fifty Dollars

• Four Hundred Fifty and 00/100 Dollars

  • or Four Hundred Fifty and xx/100 Dollars -- to prevent someone changing it to 88/100 or 99/100
  • or Four Hundred Fifty and no/100 Dollars -- also to prevent someone changing it to 88/100 or 99/100

• Four Hundred Fifty Dollars Only

• Four Hundred Fifty Only

• Four Hundred Fifty Dollars -----------------------------

• Four Hundred Fifty -------------------------------------

• Four Hundred Fifty Dollars and Zero Cents

When I write checks for even dollar amounts, I write "Four Hundred Fifty Dollars and No Sense" (I do write $450. 00/00 in number box.) I have never had an issue, much less anyone comment on it. As other answers mention, you do want to fill out the text box so it can't be altered to change the amount of your check. Whether that's a line or additional text what matters is that the amounts match, and aren't easily alterable by a third party.

Definitely valid and it is fine, but next time you can try to add only to the end of the dollar amount so there is more clarity.

We have had a check refused for deposit because of an and similar to your example. That generally precedes an amount in cents. I have never had a problem with omitting the cents, but I am always careful to draw a line from the end of the handwriting through to the pre-printed "Dollars".

I have also started using special hard-to-remove ink.

As I noted in a comment, in order to facilitate processing without human intervention, the bank has (1) announced that numbers would take precedence over contradictory words [opposite of customary practice] and (2) requested that we please write the number as 7.89 and not 7⁸⁹/₁₀₀.