“altogether” vs. “all together”

Use "altogether" as one word meaning entirely or completely, and "all together" as two words describing a group acting or gathered as one unit.

The real distinction

The test for this pair is genuinely reliable and mechanical: try removing the word "all" from the sentence entirely. If the sentence still basically makes sense without it ("the plan was different" still works, just less emphatic), you need the one-word "altogether," since "all" there is functioning as an intensifier baked permanently into the adverb. If removing "all" breaks the sentence's meaning about a group acting in unison ("we sang the song together" changes the meaning by losing the group-cohesion sense of everyone participating), you need the two-word "all together." A second, equally reliable test: try inserting another word between "all" and "together," such as "all working together" or "all sitting together" — if that insertion still makes sense, the phrase is genuinely two separate words describing a group, and you should never fuse them. "Altogether" as an adverb of degree shows up constantly in formal and analytical writing ("an altogether different approach," "altogether unconvincing"), a register where the two-word phrase would never fit grammatically. "All together" appears constantly in descriptions of groups, performances, and coordinated actions (singing all together, standing all together for the photo), a context where the one-word adverb would be a clear grammatical error, since "altogether" cannot describe people occupying the same physical space or acting in unison. A charmingly literal but genuinely useful memory anchor: "altogether" once had a specialized, now slightly old-fashioned idiomatic use meaning completely undressed ("in the altogether"), a usage still occasionally seen in older fiction and worth recognizing even though it's rare in contemporary writing. Choir directors, coaches, and event organizers giving verbal instructions rely on "all together" constantly ("sing it all together now," "let's line up all together"), a spoken context where the two-word phrase's rhythm, with a slight pause between the two words, often matches the actual cadence of the instruction being given, offering a further, purely auditory clue distinct from the deletion and insertion tests already described.

Examples with “altogether”

• The proposal was altogether different from what we expected.
• There were fifteen people at the reunion altogether.
• His explanation was altogether unconvincing.
• The renovation cost altogether more than they had budgeted.
• She found the whole situation altogether unsettling.
• The team took an altogether new approach this season.
• It was an altogether remarkable performance from start to finish.
• The two proposals were altogether incompatible with each other.

Examples with “all together”

• The choir sang the final verse all together.
• Let's get all together for a group photo before we leave.
• The siblings moved back home and lived all together for a year.
• We put the pieces all together to see the full picture.
• The volunteers worked all together to clear the debris.
• They stood all together at the finish line, cheering.
• The class recited the pledge all together each morning.
• The family gathered all together for the holiday dinner.

Memory trick

Try deleting "all" from the sentence: if the meaning survives roughly intact (just less emphatic), you need one word, "altogether"; if deleting "all" changes or breaks the sense of a group acting in unison, you need two words, "all together." A second quick test: try inserting another word between "all" and "together" ("all sitting together") — if that insertion still sounds natural, the phrase genuinely is two separate words describing a group, never the fused adverb.