Language ArtsWhen should you use "than" vs. "then"? This article explains when to use the easily confused words "than" and "then." Learn about the different parts of speech that "than" and "then" can be, their definitions, and how to differentiate them.

If I am older than you, Billy told Bobby, then I was born first. The strong similarity in spelling and pronunciation can trip us up when we try to distinguish than and then from each other. Read on to review the range of each word's meanings and to get some ideas about keeping them separate in your mind.

Than

Than is used as a conjunction and, according to some, as a preposition.

             Conjunction Than

As a conjunction is has four meanings: First, it is used as a function word to point to the second element (in sentence order) of a comparison, often following a comparative adjective or adverb:

Following Comparative Adjective: That gymnast is far more supple than I am.

Following Comparative Adverb: Eleanor wraps presents more quickly than Eliza does.

(See the articles “Adjectives” and “Adverbs” for more information about adjective and adverb forms respectively.)

Even when ellipsis is used•as it commonly is in this construction•the second item remains in the subjective case.

That gymnast is far more supple than I.

Eleanor wraps presents more quickly than she.

The second meaning of the conjunction than is to indicate difference. The difference can be of kind, of manner, or of identity.

Pat expresses himself differently than his twin does.

The third meaning is in connection with rather:

Latisha would rather visit Paris than Frankfurt.

The fourth meaning is in connection with other:

Leon would rather visit anywhere other than the state where he grew up.

There is one exception to the second item of the comparison being in the subjective case, and that is when the first item of the comparison is also objective.

Objective Case: The overpowering smell of skunk affected Don more than me.

Than can be used to compare or contrast more than two elements by adding elements on to the second named element with a conjunction:

Latisha would rather visit Paris than Frankfurt and The Hague.

Latisha would rather visit Paris than Frankfurt or The Hague.

             Preposition Than

The assignment of the four above uses of than to the part of speech conjunction is due to some grammarians' sense that the words following than should be in the subjective case unless both elements of the comparison are treated as comparison. But people often say things like:

Arthur runs faster than me.

Rather than explaining this as informal use, which is the grammarians out in many similar or related cases, their answer in this case is that than is a preposition. Since prepositions, by definition pretty much, take the objective case in their complement, this makes this construction right, though I doubt very much whether the people using this construction are thinking anything at all about substituting the prepositional use of than for the more common and more formal conjunctive use!

Anyway, that's all there is to the use of than as a preposition.

Then

Then is an adverb, noun or pronoun, and adjective. Notice that this means that than and then are never the same part of speech. While than's meanings have to do with comparisons and contrasts between items, then has to do with sequence of events in time and the logical following of one thing after another.

             Adverb Then

As an adverb, then means “at that time” or “soon after” when speaking of time and “in that case” or “as a necessary consequence” when speaking of logic. Here are examples:

There was famine in the land then.

No, no! You have it wrong: Jane went to the drugstore; then she went to the museum.

If Hans eats a quarter of the pie, then that will leave three quarters for the other seven of us to share.

It is probably the cases of adverbial then referring to logic that creates the most confusion between then and than.

            Noun or Pronoun Then

The noun or pronoun then means “at that time,” and dictionaries site the exact same usage and variously call in a noun and pronoun use, so that's why I've phrased it this way. 

This meaning is identical to one of the meanings of the adverb then, exemplified in the first sample sentence. Notice that then in that instance modifies the whole sentence. The noun then would like be found as an object•probably of a preposition, which is what would indicate that it's a noun.

Be well until then!

Since then, much water has passed under the bridge .  . .

             Adjective Then

The adjective form of then is used frequently to indicate that someone once held an office or position that they no longer hold and to speak of the person in relation to their activities in that office or position. Here's an example:

The then governor of the state asked the legislature to pass legislation including the Amber Alert Program, and they responded wholeheartedly.

Differentiating Than and Then

One of these words is for “comparison and contrast”; the other is for “time and logic.” Notice that the first descriptor has an a in each important word like than does. “Time and logic” has no a's, but it does have an e in the phrase (at the end of time) to match up with the e in then.

Written by Mary Elizabeth