WhichAI / Models / GPT-5.5 Pro

GPT-5.5 Pro

· verified September 8, 2026

public paid api in Generator reasoning

Provider

Statuspublic

AA Intelligence Index~58 (WhichAI estimate)

Releasedn/a

Context windown/a

Modalitiesn/a

API price $/1M (in / out)n/a

Speedn/a

AccessChatGPT Pro ($200/mo) · API

The score shown is a WhichAI estimate from adjacent benchmarks, not an official measurement.

In one line

Maximum-reasoning tier of GPT-5.5 - statistically tied with the very top on many boards. Overkill for everyday tasks.

Coding90

Reasoning91

Writing82

Agents & tools87

Category scores (0-100) are WhichAI blended ratings: public category leaderboards plus editorial judgment. Guidance, not official measurements.

Alternatives worth a look

GLM-5.3-Flash (Z.ai) · AA 57.5Released August 26, 2026 · open weights under MIT · API $0.15/$0.50 per 1M tokens · free chat at chat.z.ai
Claude Opus 4.8 (Anthropic) · AA 57.3Claude Pro $20/mo · API
Gemini 3.8 Flash (Google) · AA 58.7Released September 2, 2026 · API $0.75/$3.75 per 1M tokens ($0.075 cached) · free-tier availability not confirmed

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Artificial Analysis Intelligence Index, 2026 rebased scale (top models ~ 55-66). Snapshot: September 4, 2026 (BenchLM mirror), retrieved September 8, 2026. Specs and prices come from the OpenRouter public model list on the same date. Models nobody has measured carry no index score at all and never enter a ranking: where an estimate exists it is shown separately and labelled unmeasured. Context, price, modality and release dates come from the public OpenRouter model list (retrieved September 8, 2026) and vendor pages. Missing values are not published or not yet verified - shown as -. Sources are linked inside the app (Model guide and About > Methodology).