LLM WORLD

GPT-5.5

OpenAI · · 49 days after GPT-5.4

Verified

2 of 2 published values traced to a source2 primary sources, 3 archived1 not disclosed by the lab1 not researched yet

Why this status

Every value this record asserts — date (April 23, 2026) and context window (1,050,000) — was found in an archived primary source, checked 2026-08-10. Parameter count is not recorded, so nothing is claimed about it. Modalities taken from the documentation's own declaration: "Input Text, image Output Text". Capabilities evidenced from the primary sources: agentic: “1% - Model capabilities OpenAI is building the global infrastructure for agentic AI, making it possible for people and businesses around the world to get work done with A” | reasoning: “1% Evals of GPT were run with reasoning effort set to xhigh and were conducted in a research environment, which may provide slightly different output from production Chat”.

What these states mean · How records are judged · Has this record changed?

Codenamed Spud; the mid-cycle step between GPT-5.4 and the GPT-5.6 family.

reasoningagenticmultimodallong-contextflagship

Details

ReleasedApril 23, 2026
stated in openai.com, developers.openai.com

GPT-5.5 was released on April 23, 2026.

CompanyOpenAI
FamilyGPT
Lineageafter GPT-5.4
EraAgentic systems
TypeLanguage model · LLM
ModalitiesText + Image → Text
CapabilitiesReasoning, Agentic
WeightsProprietary
LicenceNot applicable — proprietary
Context window1.05M tokens
stated in developers.openai.com

GPT-5.5 supports a context window of 1,050,000 tokens.

ParametersNot disclosed

Pricing

The price a lab's own page showed on the day that page was captured. That is what a snapshot can prove; it is not necessarily the launch price, and prices are often cut later. Citing the live pricing page instead would give a number with no date at all.

Input $5 per million tokens observed April 24, 2026 · archived snapshot (2026-04-24)
Output $30 per million tokens observed April 24, 2026 · archived snapshot (2026-04-24)

Benchmarks

Each row is a dated claim by a named party, not a property of the model. A later revision adds a row rather than replacing one. This project publishes no composite or overall score.

BenchmarkScoreReported byDate
OSWorld78.7 Vendor reportedApril 23, 2026

Current information, elsewhere

This record is a historical one: every figure above is traced to a dated primary source. For what is true today — live pricing, current rankings, availability — these are better maintained than anything here could be.

Sources

Record status: verified · confidence 90/100 · 2 of 3 primary

Every value this record asserts — date (April 23, 2026) and context window (1,050,000) — was found in an archived primary source, checked 2026-08-10. Parameter count is not recorded, so nothing is claimed about it. Modalities taken from the documentation's own declaration: "Input Text, image Output Text". Capabilities evidenced from the primary sources: agentic: “1% - Model capabilities OpenAI is building the global infrastructure for agentic AI, making it possible for people and businesses around the world to get work done with A” | reasoning: “1% Evals of GPT were run with reasoning effort set to xhigh and were conducted in a research environment, which may provide slightly different output from production Chat”.

Primary means published by the organisation that made the model. Verified records require at least one.

GPT family

  1. GPT-4 March 14, 2023
  2. GPT-4o May 13, 2024
  3. GPT-4.5 February 27, 2025
  4. GPT-5 August 7, 2025
  5. GPT-5.1 November 12, 2025
  6. GPT-5.2 December 11, 2025
  7. GPT-5.3-Codex February 5, 2026
  8. GPT-5.4 March 5, 2026
  9. GPT-5.5 April 23, 2026
  10. GPT-5.6 Sol July 9, 2026
  11. GPT-5.6 Luna July 9, 2026
  12. GPT-5.6 Terra July 9, 2026
  13. GPT-5.6-Cyber August 10, 2026
  14. GPT-6 Astra September 3, 2026
  15. GPT-Rosalind September 8, 2026
  16. GPT-6 Sol September 22, 2026
  17. GPT-6 Luna September 22, 2026
  18. GPT-6.1 Sol September 29, 2026

What changed from GPT-5.4

Compared with the previous release in this series. A field appears only when both records state a value — where one does not, it is listed as uncomparable rather than dropped, because a gap in our research is not a finding about the model.

Not comparable: Parameters (not disclosed for both releases)

Compare them side by side →

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See GPT-5.5 on the interactive timeline →