GPT-5.5 vs GPT-4o: Is It Time to Retire GPT-4o?

	GPT-5.5	GPT-4o
arenaElo	1432	1345
humanEval	94.2	90.2
sweBench	66	33
mmlu	93	88.7
gpqa	68.7	53.6
aime	92	42
Price in/out ($/M)	$12 / $48	$2.5 / $10

Our verdict

GPT-5.5 beats GPT-4o on every benchmark by double digits and has 4.5× the context. GPT-4o only stays relevant for pipelines that depend on the Realtime API voice stack. New builds should start on GPT-5.5.

GPT-5.5 · GPT-4o · All AI model comparisons