Lifetime is one word. There is no gap in it, ever, no matter how formal or casual the writing is. “Life time” as two separate words is simply not standard English, and “life-time” with a hyphen is an outdated form you’ll rarely see outside old books. If you’re typing a warranty claim, a dating profile, or a college essay, write lifetime as a single closed compound.
The Short Answer
Lifetime is a closed compound noun, meaning the two original words (life + time) fused into one permanently accepted word decades ago. Dictionaries like Merriam-Webster and Oxford list only the one-word spelling. You won’t find “life time” as a valid alternative in any current style guide.
- Correct: lifetime
- Incorrect: life time
- Outdated/rare: life-time
Why People Get It Wrong
The confusion usually comes from two places. First, “life” and “time” are both familiar standalone words, so the brain wants to keep them apart the way you’d write “long time” or “hard life.” Second, older printed material really did use “life-time” with a hyphen, and some of that habit lingers in how people type today, especially when typing fast or relying on autocorrect that doesn’t always catch it.
English compounds tend to move through three stages over time: two words, then hyphenated, then one solid word. “Lifetime” has already completed that journey. Compare it to “email,” which started as “e-mail” and is now almost always written solid.
Examples in a Sentence
- This blender comes with a lifetime warranty.
- She said it was the opportunity of a lifetime.
- He’s lived in this town his entire lifetime.
- A tortoise’s lifetime can stretch past 100 years.
When “Life” and “Time” Really Are Separate Words
There’s one case where a space is correct, and it trips people up. If “life” is modifying a different noun than “time,” and “time” is functioning on its own within a longer phrase, you’re not dealing with the compound at all. This is rare, but it happens in constructions like “the life span” versus “time span,” where the two nouns simply aren’t forming the same compound. In everyday use, though, whenever you mean “the duration of someone’s life” or “throughout someone’s whole existence,” you want the single word.
Lifetime as an Adjective
Lifetime also works as an adjective, and it still stays one word: “a lifetime achievement award,” “a lifetime membership,” “a lifetime guarantee.” No hyphen needed before the noun it modifies, unlike some compound adjectives.
| Form | Status | Example |
|---|---|---|
| lifetime | Correct, standard | a lifetime of memories |
| life time | Incorrect | — |
| life-time | Archaic, avoid | — |
| lifelong | Different word, also one word | a lifelong friend |
Key Takeaways
- Lifetime is always written as one solid word in modern English.
- “Life time” (two words) and “life-time” (hyphenated) are not standard spellings today.
- It functions as both a noun (“the trip of a lifetime”) and an adjective (“lifetime warranty”).
- The hyphenated form was once common but has fallen out of use over the last century.
- When in doubt, treat it like “lifelong” or “lifestyle”: no space, no hyphen.
Frequently Asked Questions
Is it “lifetime” or “life time” in formal writing?
It’s “lifetime,” one word, in every register of writing, formal or informal. Style guides and dictionaries agree there is no accepted two-word version.
Is “life-time” with a hyphen ever correct?
It appears in older texts, but current style guides treat it as outdated. Stick with the closed form, “lifetime,” for anything you write today.
What’s the difference between “lifetime” and “lifelong”?
“Lifetime” is typically a noun describing the whole span of someone’s life (“a lifetime of hard work”), while “lifelong” is an adjective meaning something that lasts through an entire life (“a lifelong dream”). Both are single words.
Does “lifetime warranty” need a hyphen between the words?
No. “Lifetime” stays as one word and simply sits in front of “warranty” with no hyphen: “lifetime warranty,” not “life-time warranty” or “life time warranty.”
Why does autocorrect sometimes suggest “life time”?
Autocorrect tools aren’t perfect and occasionally flag correctly spelled compounds, especially if you’ve typed quickly or if the tool’s dictionary is outdated. Trust the standard dictionary spelling, “lifetime,” over an autocorrect suggestion.
Once you’ve got “lifetime” locked in, you’ll start noticing how many other compound words follow the same one-word, hyphenated, two-word journey. Poke around the site for more of these quick spelling fixes.
