Home / Compare / Phi 4 vs GPT-5.5

Phi 4 vs GPT-5.5

For a typical chat reply (2,000 tokens in, 400 out), GPT-5.5 costs 112× as much as Phi 4: $22.00 against $0.196 per 1,000 requests at list price on 2026-09-28.

Phi 4GPT-5.5
Input, per 1M tokens$0.07$5.00
Output, per 1M tokens$0.14$30.00
Context window16K1.05M
Classification or routing (600 tokens in, 10 out), per 1,000$0.0434$3.30
Chat reply (2,000 in, 400 out), per 1,000$0.196$22.00
Retrieval-augmented answer (8,000 in, 500 out), per 1,000$0.63$55.00
Confidence signalnono
Tool callingnoyes

Which one should carry your traffic?

If Phi 4 answers your requests as well as GPT-5.5, moving that traffic saves 99% on chat-shaped requests. Averages cannot tell you whether it does for your requests. Phi 4 does not expose a confidence signal through OpenRouter, so Gimbix would test it as a full replacement rather than a first answer.

Phi 4 profile · GPT-5.5 profile · Measure it on your traffic