NotesByLex

GPT-6 Sol

GPT-6 Sol is OpenAI's mid-sized GPT-6 model, released alongside GPT-6 Luna on 22 September 2026 (openaiAPIChangelog). OpenAI says it's "built to power complex coding and agentic workflows" (OpenAI).

It's half Claude Opus 5.5's price for uncached input and output (OpenAI). OpenAI's docs now point to a newer version, GPT-6.1 Sol, at the same input and output prices (OpenAI).

The wider release, benchmarks and a hands-on example are in GPT 6 Sol and Luna. For the small model, see GPT-6 Luna.

Specs

Specification GPT-6 Sol
API identifier gpt-6-sol
Input / output Text and images / text
Context window 1,050,000 tokens (922,000 max input)
Maximum output 128K tokens
Knowledge cutoff 20 April 2026
Effort levels none to max, default medium

As of 14 October 2026 (OpenAI). For tool calls with reasoning on, use the Responses API.

Pricing

USD per million tokens, verified 14 October 2026. Over 272K input tokens, the whole request pays the higher rate (OpenAI).

Usage Up to 272K Over 272K
Input, uncached $2.00 $4.00
Input, cache read $0.20 $0.40
Cache write $2.50 $5.00
Output, including reasoning $10.00 $15.00

Batch and Flex are half price. Fast mode is double.

References

Changelog \textbar OpenAI API. https://developers.openai.com/api/docs/changelog. ↩

OpenAI. Pricing. Living documentation. Accessed 8 October 2026. URL: https://developers.openai.com/api/docs/pricing (visited on 2026-10-08). ↩

OpenAI. GPT-6 Sol. Living documentation. Accessed 14 October 2026. URL: https://developers.openai.com/api/docs/models/gpt-6-sol (visited on 2026-10-14). ↩ 1 2 3

OpenAI. GPT-6.1 Sol. Living documentation. Accessed 14 October 2026. URL: https://developers.openai.com/api/docs/models/gpt-6.1-sol (visited on 2026-10-14). ↩