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GPT-5.5

OpenAI · released 23 Apr 2026 · proprietary API

OpenAI flagship; first OpenAI model with a 1M-token API context window.

Context window

1.05M

1,050,000 tokens

Input price

$5

per 1M tokens

Output price

$30

per 1M tokens

Blended

$11.25

3:1 in:out mix

Weights

Proprietary

API only

Released

23 Apr 2026

OpenAI

Long-context / tier pricing — >272K input billed 2x input / 1.5x output. Listed prices are the base rate for prompts up to ~200K tokens.

Where it ranks

Of the 16 models tracked, GPT-5.5 is #15 cheapest to run (blended $/1M at a 3:1 input:output mix), #14 (tied) by input price, and #1 by context window.

See the full Frontier Index →

Compare with

The nearest models by blended cost to run.

Put it to work

Specs from BitByteCore's hand-verified Frontier Ledger (v2026-07-04, verified 21 Jun 2026). Model pricing moves fast — confirm with OpenAI before you rely on a figure.