I was surprised that my spell checker did not complain for programing with one m, so I Googled it, and found on free dictionaries that both forms were acceptable.

  • Which one is more common? Does it depend on the geographical location? My perception is that the spelling two m’s seems to dominate.
  • Is this part of a more general word formation rule, or mostly an exception?
  • 6
    I would not take the existence of both spellings as indicative that both were “acceptable”. The overwhelming preference for the version with two m’s has to mean something. It is easy to find minority spellings of no end of English words which most people would not find acceptable for use in their own writing.
    – tchrist
    May 4, 2015 at 12:48
  • 1
    We have a wealth of knowledge on this subject, see the dedicated tag.
    – RegDwigнt
    May 4, 2015 at 14:38
  • 5
    As an avid programmer, I find that programming is more often used.
    – AJF
    May 4, 2015 at 15:28
  • 6
    @AJ As an avid programmer, I've never seen programing used.
    – HarryCBurn
    May 4, 2015 at 21:10
  • 3
    I have never in my life seen 'programing' in print until I saw this question, and I've been doing it since 1971.
    – user207421
    May 4, 2015 at 22:43

3 Answers 3


You may have noticed that "programmed" and "programming" stand as an exception to the usual tendency for final consonant doubling to occur in two-syllable words only when the second syllable is stressed (for example, we double the final r in occurring but not in harboring). I use "tendency" guardedly here: Various other exceptions to this tendency exist, and proponents can readily be found for either side in the debate over such unsettled forms as labeling/labelling and leveling/levelling.

Anyway, in U.S. English—or rather, in the representation of U.S. spelling preferences offered in the Merriam-Webster Collegiate Dictionary series—the initial preference with regard to the -ed and -ing forms of the verb program was for no consonant doubling. The debut of program as a verb came in the Collegiate Dictionary's Sixth Edition (1949):

program v.t. PROGRAMED or PROGRAMMED; PROGRAMING or PROGRAMMING. Also programme. To arrange or furnish a program of or for; to enter in a program; to bill.

I believe that the impetus for this preference was the syllable stress test; certainly that would be consistent with the fact that programmatic (where the greatest stress falls on the third syllable) is listed with only the double-m spelling.

Anyway, actual usage led to a reversal of the Sixth Collegiate's order of preference. The Seventh Collegiate (1963) gives the double-m spellings first:

program also programme vt programmed or programed; programming or programing 1 a : to arrange or furnish a program of or for : BILL b : to enter in a program 2 : to work out a sequence of operations to be performed by (as an electronic computer) — programmer

Notice that programer is not an option here. It is quite possible that, going forward, the central role of computers as the objects of programming made the spelling preferences of computer engineers and developers especially significant. In any case, when the computer-related definition of the verb program arrived in the dictionary, the spelling preference flipped.

It flipped, but programed and programing didn't vanish altogether. In fact those spellings still appear as alternative spellings in the Eleventh Collegiate (2003). But the weight of real-world usage is overwhelmingly in favor of doubling the m, as this Ngram chart of programed (blue line) and programing (red line) versus programmed (green line) and programming (yellow line) for the period 1930–2005 indicates:

And here's how the early years (1930–1965) of the contest look, for closer comparison:

This chart strongly suggests that programed and programing never enjoyed a significant advantage in published writing over their double-m counterparts, so perhaps Merriam-Webster had been backing the wrong horses all along. In any case, that dictionary still honors the uncommon single-m spellings by treating them as full-fledged variants, as does the American Heritage Dictionary of the English Language (which is the primary dictionary relied on by Microsoft Word)—and that's why your spelling checker, by default, doesn't flag it.

  • 4
    I should perhaps add that the British spelling programme for the verb doesn't require any doubling because it already has a double m. The British preference for the double-m versions of the -ed and -ing forms may well have given programmed and programming a boost in overall preferability that they wouldn't have enjoyed on the strength of their U.S. figures alone.
    – Sven Yargs
    May 4, 2015 at 8:34
  • 2
    There might also be an etymological basis, much like how "crystallize" is spelled with two "l"s despite "crystal" only having one.
    – herisson
    May 4, 2015 at 8:41
  • 2
    In general US speech, at least, program is pronounced with two consecutive stressed syllables (the second one holding secondary stress). May 4, 2015 at 18:38
  • 2
    I think that stress is only a secondary factor (if that), after vowel quality; we don't double the consonant after a tense ("long") vowel, we do double it after a lax ("short") vowel, and we follow more-complex rules for reduced vowels. (With some caveats; for example, I think most dialects nowadays distinguish /ɝ/ from /ɚ/ only by stress, so <offered> vs. <referred> ends up being stress-driven.) So I suspect that the <programed> reflects a pronunciation /'pro.grəmd/.
    – ruakh
    May 5, 2015 at 1:50
  • @echristopherson Indeed, and "format" likewise, hence programming & formatting vs welcoming & marketing. Evidence that the root verb's last syllable has stress (albeit secondary) is that it has more stress than the final -ing.
    – Rosie F
    Apr 23, 2019 at 10:31

Quite clearly the word at fault is "program".

Here in the U.K. the Americanism "program" conveniently encompassed the computer meaning from earliest days. Thus, over here we can "program" our computer while watching a TV "programme" and the distinction is obvious even if "computer" or "TV" aren't mentioned.

Sadly, it doesn't seem that the aesthetically awkward "programing/programed" has gained any significant usage and therefore "computer programming" is still the preferred option, irrespective of any linguistic rules. I say sadly because it has been very handy to have the differential between "programme" and "program" - two clear and different meanings, but only for us Brits it seems!

  • As I read these comments I was rooting for 'Programing' for exactly the reasons so clearly referred to above. However, when I checked my text books from the 1970's & 80's, the majority of them referred to 'Programming'!
    – Seldon2k
    Aug 8, 2017 at 16:08

The word programming is a Greek word. In Greek the word is "προγραμματισμός" (programmatismos). It refers basically to words united together. The first word is the pro or in Greek "προ" and it means first or front or before. The second word is the gramming or in Greek "γραμματισμος" (grammatismos). "γραμμα" (gramma) means letter. So if in Greek the word "γραμμα" (gramma) writing with two m's then the word in English must be with two m's.

  • Bu the word "program" is often written with one "m" in spite of the Greek spelling.
    – herisson
    Nov 21, 2015 at 7:17
  • 6
    I find this irrelevant. Any Greek-derived words in English were derived so long ago (and generally, as in this case, via Latin) that any expectation of spelling conformity is ridiculous. The Greek spelling is an interesting observation, but has no relevance to the English spelling.
    – Hot Licks
    Nov 21, 2015 at 8:18