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OpenAI

GPT-5.6 Sol

GPT-5.6 Sol is a OpenAI model with 1.05M context, $4 in / $20 out per million tokens, last verified October 1, 2026. Open weights: no. Status: Superseded since September 22, 2026; the current pick is GPT-6 Sol. Public-board scores are linked to the publisher; vendor-only figures stay in the watch-out, not on the board.

GPT-5.6 Sol was OpenAI's GPT-5.6 flagship for complex reasoning and coding with a 1.05M-token context — superseded on 2026-09-22 by GPT-6 Sol at half the price.

Recorded profile verification October 1, 2026Individual provider fields may change

AI model specification details
SpecificationGPT-5.6 Sol
ProviderOpenAI
TierFrontier
Context window1.05M
Max output128K
Input / 1M tokens$4
Output / 1M tokens$20
WeightsClosed
ParametersNot verifiedUnverified
Reasoning levelsnone, low, medium, high, xhigh, max
Modalitiestext, image
API model idgpt-5.6-sol
ReleasedJuly 9, 2026

Pricing tiers: Launch $5/$30, reduced to promotional $4/$20 on August 21; available at least through November 21, 2026. Above 272K input the full request bills $8/$30. Cached input $0.40/$0.80 short/long and cache writes $5/$10. Batch is $2/$10 at short context. Regional/FedRAMP processing adds 10% where eligible. Knowledge cutoff Feb 16 2026.

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-5.6 Sol
BenchmarkScoreSource dateSource
Terminal-Bench 2.188.8%2026-07-09OpenAI — GPT-5.6 evals table (vendor; Ultra multi-agent config: 91.9) · View source
GPQA Diamond94.6%2026-07-09OpenAI — GPT-5.6 evals table (vendor) · View source

Best for

  • Complex reasoning
  • Agentic coding
  • Hard knowledge work

Watch out

GPT-6.1 Sol is the newer Sol option at $2/$10 Standard. GPT-5.6 Sol remains listed; its $4/$20 price is promotional. Max effort can increase token use, and Ultra is a multi-agent configuration rather than a separate reasoning.effort value.

History

GPT-5.6 Sol timeline

Release and status events for this model that passed two-source verification — dated, sourced, and linked.

Source receipts

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

Common questions

GPT-5.6 Sol

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

How much does GPT-5.6 Sol cost per million tokens?
GPT-5.6 Sol lists base rates of $4 per million input tokens and $20 per million output tokens. Estimate both input and output token volume and any additional charges for your workload. Launch $5/$30, reduced to promotional $4/$20 on August 21; available at least through November 21, 2026. Above 272K input the full request bills $8/$30. Cached input $0.40/$0.80 short/long and cache writes $5/$10. Batch is $2/$10 at short context. Regional/FedRAMP processing adds 10% where eligible. Knowledge cutoff Feb 16 2026.
What is GPT-5.6 Sol's context window?
GPT-5.6 Sol 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-5.6 Sol best for?
GPT-5.6 Sol is a frontier tier from OpenAI. It suits complex reasoning, agentic coding, hard knowledge work. GPT-6.1 Sol is the newer Sol option at $2/$10 Standard. GPT-5.6 Sol remains listed; its $4/$20 price is promotional. Max effort can increase token use, and Ultra is a multi-agent configuration rather than a separate reasoning.effort value.
Model comparison catalogBenchmark library