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OpenAI

GPT-5.5

GPT-5.5 is a OpenAI model with 1.05M context, $5 in / $30 out per million tokens, last verified October 25, 2026. Open weights: no. Status: Legacy. Public-board scores are linked to the publisher; vendor-only figures stay in the watch-out, not on the board.

OpenAI’s April 2026 model for reasoning, coding and professional work, with a 1.05M-token context. Retained benchmark scores identify their source and configuration.

Recorded profile verification October 25, 2026Individual provider fields may change

AI model specification details
SpecificationGPT-5.5
ProviderOpenAI
TierFrontier
Context window1.05M
Max output128K
Input / 1M tokens$5
Output / 1M tokens$30
WeightsClosed
ParametersNot verifiedUnverified
Reasoning levelsnone, low, medium, high, xhigh
Modalitiestext, image
API model idgpt-5.5
ReleasedApril 23, 2026

Pricing tiers: All amounts are USD per MTok; long-context bands apply to the full request, not just excess tokens. Standard <=272K input: input/output $5.00/$30.00, cached input $0.50, 30-minute write not quoted, 12-hour write not quoted; >272K: input/output $10.00/$45.00, cached input $1.00, 30-minute write not quoted, 12-hour write not quoted. Batch <=272K input: input/output $2.50/$15.00, cached input $0.25, 30-minute write not quoted, 12-hour write not quoted; >272K: input/output $5.00/$22.50, cached input $0.50, 30-minute write not quoted, 12-hour write not quoted. Flex <=272K input: input/output $2.50/$15.00, cached input $0.25, 30-minute write not quoted, 12-hour write not quoted; >272K: input/output $5.00/$22.50, cached input $0.50, 30-minute write not quoted, 12-hour write not quoted. Fast <=272K input: input/output $12.50/$75.00, cached input $1.25, 30-minute write not quoted, 12-hour write not quoted; >272K: input/output not quoted/not quoted, cached input not quoted, 30-minute write not quoted, 12-hour write not quoted. Regional processing and FedRAMP add 10% where the model and route are eligible; region eligibility is separate from a quoted tariff. Server-side tools and their tokens can add charges. The model card applies the >272K surcharge to the full session in Standard/Batch/Flex. Row captions say <272K while the table band definition says <=272K; confirm any boundary-sensitive billing. Cache-write cells are not quoted.

Publisher evidence

Published benchmark results

Each result keeps its source date visible. Dates refer to source publication or capture unless the source explicitly states when it measured the result. A missing benchmark is not treated as a zero.

Published benchmark results for GPT-5.5
BenchmarkScoreSource dateSource
Terminal-Bench 2.183.4%2026-07-27Kimi K3 model card (vendor-reported, xhigh, Codex harness; orig OpenAI) · View source
GPQA Diamond93.5%2026-07-27Kimi K3 model card (vendor-reported, xhigh); announcement charts show 93.6 — minor conflict preserved · View source
Humanity's Last Exam52.2%2026-04-23OpenAI — Introducing GPT-5.5 (vendor, with tools; 41.4 no tools) · View source

Best for

  • Reasoning
  • Agentic coding
  • Long-context work

Watch out

Still listed as an API model. The October 14, 2026 retirement notice covered ChatGPT, Work and Codex; it did not announce an OpenAI API shutdown. Preserve exact model/snapshot and original benchmark settings when comparing the older generation.

Source receipts

Catalog figures for this model were checked against the following sources.

Common questions

GPT-5.5

Answered from the verified figures on this page rather than general guidance.

How much does GPT-5.5 cost per million tokens?
GPT-5.5 lists base rates of $5 per million input tokens and $30 per million output tokens. Estimate both input and output token volume and any additional charges for your workload. All amounts are USD per MTok; long-context bands apply to the full request, not just excess tokens. Standard <=272K input: input/output $5.00/$30.00, cached input $0.50, 30-minute write not quoted, 12-hour write not quoted; >272K: input/output $10.00/$45.00, cached input $1.00, 30-minute write not quoted, 12-hour write not quoted. Batch <=272K input: input/output $2.50/$15.00, cached input $0.25, 30-minute write not quoted, 12-hour write not quoted; >272K: input/output $5.00/$22.50, cached input $0.50, 30-minute write not quoted, 12-hour write not quoted. Flex <=272K input: input/output $2.50/$15.00, cached input $0.25, 30-minute write not quoted, 12-hour write not quoted; >272K: input/output $5.00/$22.50, cached input $0.50, 30-minute write not quoted, 12-hour write not quoted. Fast <=272K input: input/output $12.50/$75.00, cached input $1.25, 30-minute write not quoted, 12-hour write not quoted; >272K: input/output not quoted/not quoted, cached input not quoted, 30-minute write not quoted, 12-hour write not quoted. Regional processing and FedRAMP add 10% where the model and route are eligible; region eligibility is separate from a quoted tariff. Server-side tools and their tokens can add charges. The model card applies the >272K surcharge to the full session in Standard/Batch/Flex. Row captions say <272K while the table band definition says <=272K; confirm any boundary-sensitive billing. Cache-write cells are not quoted.
What is GPT-5.5's context window?
GPT-5.5 accepts about 1.05M tokens of context. That only matters if you routinely send very long documents, large codebases, or multi-turn histories that approach that limit.
What is GPT-5.5 best for?
GPT-5.5 is a frontier tier from OpenAI. It suits reasoning, agentic coding, long-context work. Still listed as an API model. The October 14, 2026 retirement notice covered ChatGPT, Work and Codex; it did not announce an OpenAI API shutdown. Preserve exact model/snapshot and original benchmark settings when comparing the older generation.
Model comparison catalogBenchmark library