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GPT-5.4 vs GPT-5.5

For a typical chat reply (2,000 tokens in, 400 out), GPT-5.5 costs 2.0× as much as GPT-5.4: $22.00 against $11.00 per 1,000 requests at list price on 2026-09-28.

GPT-5.4GPT-5.5
Input, per 1M tokens$2.50$5.00
Output, per 1M tokens$15.00$30.00
Context window1.05M1.05M
Classification or routing (600 tokens in, 10 out), per 1,000$1.65$3.30
Chat reply (2,000 in, 400 out), per 1,000$11.00$22.00
Retrieval-augmented answer (8,000 in, 500 out), per 1,000$27.50$55.00
Confidence signalnono
Tool callingyesyes

Which one should carry your traffic?

If GPT-5.4 answers your requests as well as GPT-5.5, moving that traffic saves 50% on chat-shaped requests. Averages cannot tell you whether it does for your requests. GPT-5.4 does not expose a confidence signal through OpenRouter, so Gimbix would test it as a full replacement rather than a first answer.

GPT-5.4 profile · GPT-5.5 profile · Measure it on your traffic