“Cancelled” or “Canceled”?

Question

Cancelled or Canceled ? Which one is right?

You have successfully canceled the registration

or

You have successfully cancelled the registration

Answer 1

The past tense of cancel is strictly cancelled in British English (BrE). In American English (AmE), however, it is spelled (BrE spelt!) canceled. Note that cancelled is also acceptable in American usage. There are many other verbs whose past tenses and present participles follow a similar pattern:

• worship: worshiped (AmE)/worshipped (BrE) • worshiping (AmE)/worshipping (BrE)
• travel: traveled (AmE)/travelled (BrE) • traveling (AmE)/travelling (BrE)
• label: labeled (AmE)/labelled (BrE) • labeling (AmE)/labelling (BrE)
• libel: libeled (AmE)/libelled (BrE) • libeling (AmE)/libelling (BrE)
• devil: deviled (AmE)/devilled (BrE) • deviling (AmE)/devilling (BrE)

There are some notable exceptions in which the last consonant is always doubled in the past tense and present participle. Examples:

• compel: compelled • compelling
• corral: corralled • corralling
• repel: repelled • repelling
• refer: referred • referring
• occur: occurred • occurring
• demur: demurred • demurring
• whip: whipped • whipping
• fit: fitted • fitting

And there also those words whose last consonant is never doubled when forming the past tense or present participle. Examples:

• differ: differed • differing
• succo[u]r: succo[u]red • succo[u]ring
• solicit: solicited • soliciting
• gallop: galloped • galloping

A special example is the verb program[me]:

• (AmE) program: programed/programmed • programing/programming
• (BrE) programme: programmed • programming

Answer 2

See the number of occurrences of cancelled and canceled from the American Corpus and British Corpus below. This supports what @JoseK wrote as comment to the question:

Corpus of Contemporary American English (COCA):

 CANCELED   3746     
 CANCELLED  640

British National Corpus:

 CANCELLED 1194
 CANCELED   1

Answer 3

The American system for forming the past tense of these verbs usually follows these rules:

1. If the final vowel is long, leave a single consonant, as otherwise a double consonant would convert the vowel to short: reviled, amazed, completed.
2. Else, if the stress is on the final syllable, double the final consonant, same as the British system: compelled, deferred.
3. Else, if the final vowel is e, we leave it single: traveled, canceled.
4. Else, it varies. For the vowels a and i, I think it's standard to leave the vowel single: kidnaped, worshiped. But to me that looks like it's a long vowel, and I think it looks better with the consonant doubled, which I believe is also acceptable: kidnapped, worshipped.

Answer 4

It can be both, 'canceled and 'cancelled'. But to me, 'cancelled' looks way better than 'canceled'.

P.S.-Nice play on the words 'canceled' and 'cancelled'!!!!! Seems quite a tongue twister!