GPT-5.5 Pro

Tool callingStructured outputReasoningImage inputFile input

Launch post Website Docs

Highest-accuracy GPT-5.5 tier for slower, precision-heavy reasoning and coding

Context: 1.1M
Released: 5mo ago
Input / 1M tokens: $30.00
Output / 1M tokens: $180.00

Sources:models.devOpenRouter

Benchmarks

DeepSWE is the primary coding benchmark where an exact model evaluation exists. Other sourced evaluations appear below; missing scores are not zero.

Not evaluated in DeepSWE 1.1 as of 2026-09-22. Results are only shown for exact model versions in the official dataset. Official leaderboard.

Other published benchmarks

Evaluation	Reported score and source
ARC-AGI-2	84.6% Third-party evaluator · gpt-5.5-pro_high Reasoning effort: high External evaluation via Epoch AI Original-source terms apply
ARC-AGI-2	84.2% Third-party evaluator · gpt-5.5-pro_xhigh Reasoning effort: xhigh External evaluation via Epoch AI Original-source terms apply
FrontierMath-Tier-4-v2-Private	78.0% Epoch AI · gpt-5.5-pro_xhigh Reasoning effort: xhigh Epoch AI evaluation
FrontierMath-Tiers-1-3-v2-Private	87.7% Epoch AI · gpt-5.5-pro_xhigh Reasoning effort: xhigh Epoch AI evaluation

Benchmark compilation: Epoch AI, Capabilities & benchmarking (CC BY attribution). Scores are converted to percentages and model names matched to the Vertical Tabs catalog. Individual evaluations are credited to their original sources. External results may carry separate licences and evaluation configurations; do not interpret scores from different harnesses as directly comparable.

Specifications

Developer: OpenAI
Model family: GPT
Type: Language model
Predecessor: —
Successor: —
Released: April 23, 2026
Model ID: openai/gpt-5.5-pro
Openness: Closed
License: —
Input modalities: file, image, text
Output modalities: text
Modality: text+image+file->text
Tokenizer: GPT
Max output tokens: 128K
Knowledge cutoff: 2025-12-01
Hugging Face: —
Source freshness: Metadata synced Oct 8, 2026, 10:17 PM UTC

Additional source evidence

Source model: openai/gpt-5.5-pro
Source family: gpt-pro
Last updated: 2026-04-23
Knowledge cutoff: 2025-12-01
Model context: 1.1M
Maximum input: 922K
Model output limit: 128K
Open weights: No
File attachments: Yes
Reasoning: Yes
Tool calling: Yes
Structured output: Yes
Temperature control: No

Published benchmarks

Benchmark	Score	Evaluation details	Evidence
BrowseComp	90.1 · accuracy	2026-04-23	Source
Humanity's Last Exam	43.1 · accuracy	no tools · 2026-04-23	Source
Humanity's Last Exam	57.2 · accuracy	with tools · 2026-04-23	Source
FrontierMath	52.4 · accuracy	Tier 1-3 · 2026-04-23	Source
FrontierMath	39.6 · accuracy	Tier 4 · 2026-04-23	Source
GDPval	82.3 · wins or ties	2026-04-23	Source
GeneBench	33.2 · accuracy	2026-04-23	Source

Complete source record (JSON)

{
  "id": "openai/gpt-5.5-pro",
  "name": "GPT-5.5 Pro",
  "description": "Highest-accuracy GPT-5.5 tier for slower, precision-heavy reasoning and coding",
  "family": "gpt-pro",
  "last_updated": "2026-04-23",
  "knowledge": "2025-12-01",
  "attachment": true,
  "reasoning": true,
  "tool_call": true,
  "structured_output": true,
  "temperature": false,
  "modalities": {
    "input": [
      "text",
      "image",
      "pdf"
    ],
    "output": [
      "text"
    ]
  },
  "limit": {
    "context": 1050000,
    "input": 922000,
    "output": 128000
  },
  "benchmarks": [
    {
      "name": "BrowseComp",
      "score": 90.1,
      "source": "https://openai.com/index/introducing-gpt-5-5/",
      "metric": "accuracy",
      "date": "2026-04-23"
    },
    {
      "name": "Humanity's Last Exam",
      "score": 43.1,
      "source": "https://openai.com/index/introducing-gpt-5-5/",
      "metric": "accuracy",
      "variant": "no tools",
      "date": "2026-04-23"
    },
    {
      "name": "Humanity's Last Exam",
      "score": 57.2,
      "source": "https://openai.com/index/introducing-gpt-5-5/",
      "metric": "accuracy",
      "variant": "with tools",
      "date": "2026-04-23"
    },
    {
      "name": "FrontierMath",
      "score": 52.4,
      "source": "https://openai.com/index/introducing-gpt-5-5/",
      "metric": "accuracy",
      "dataset": "Tier 1-3",
      "date": "2026-04-23"
    },
    {
      "name": "FrontierMath",
      "score": 39.6,
      "source": "https://openai.com/index/introducing-gpt-5-5/",
      "metric": "accuracy",
      "dataset": "Tier 4",
      "date": "2026-04-23"
    },
    {
      "name": "GDPval",
      "score": 82.3,
      "source": "https://openai.com/index/introducing-gpt-5-5/",
      "metric": "wins or ties",
      "date": "2026-04-23"
    },
    {
      "name": "GeneBench",
      "score": 33.2,
      "source": "https://openai.com/index/introducing-gpt-5-5/",
      "metric": "accuracy",
      "date": "2026-04-23"
    }
  ],
  "release_date": "2026-04-23",
  "open_weights": false
}

Infrastructure

Provider availability

All providers

Provider	Endpoint	Context	Input /M tokens	Output /M tokens	Cached input /M tokens	Cache write /M tokens	Uptime 1d	Data handling
OpenAI	openai/flex	1.1M	$15.00	$90.00	—	—	—	ZDR: No Training: Unknown Prompt logging: Unknown Retention: Unknown ZDR source Privacy policy Checked 2026-10-15
OpenAI	openai/flexBatch pricing	1.1M	$15.00	$90.00	—	—	—	ZDR: No Training: Unknown Prompt logging: Unknown Retention: Unknown ZDR source Privacy policy Checked 2026-10-15
OpenAI	openai	1.1M	$30.00	$180.00	—	—	100.00%	ZDR: No Training: Unknown Prompt logging: Unknown Retention: Unknown ZDR source Privacy policy Checked 2026-10-15
OpenAI	openaiBatch pricing	1.1M	$30.00	$180.00	—	—	100.00%	ZDR: No Training: Unknown Prompt logging: Unknown Retention: Unknown ZDR source Privacy policy Checked 2026-10-15

Provider data:OpenRouter

Text provenance

EU · product-scoped

OpenAI textGrain watermarking

In the EU, ChatGPT-generated text uses textGrain. OpenAI says API customers can opt in globally for select models, so watermarking depends on the product surface and configuration.

Official explanation