ZMIME
OpenAI · Released Jul 9, 2026

GPT-5.6 Sol

Frontier GPT-5.6 model for complex professional work, coding, and agentic workflows.

  • Proprietary
  • Reasoning
  • Tool calling
  • Vision
Capability
161.8ECI · #8 of 148
Input
$4.00per 1M tokens
Output
$20.00per 1M tokens
Context
1.05M128K max output
Pricing

What it costs

Input
$4.00per million tokens
Output
$20.00per million tokens
Cached input
$0.40per million tokens
Cache write
$5.00per million tokens
Over 272K tokens
$8.00 / $30.00input / output per million
Blended (3:1)
$8.00pricier than 92% of priced models

Typical monthly bills

Monthly usageEstimated cost
Side project2M input + 0.5M output tokens$18.00
Team assistant25M input + 5M output tokens$200.00
Production app250M input + 50M output tokens$2,000

Official OpenAI API price, as listed on models.dev.

Capability

Independent benchmarks

161.8Epoch Capabilities Index
#8 of 148 scored models
88Median 146167

The shaded band is Epoch AI’s confidence range (159.3–165.3); the tick marks the median scored model.

  • GPQA DiamondGraduate-level science questions · max setting93.5%
  • FrontierMath Tiers 1–3Research-level mathematics · max setting89.1%
  • OTIS Mock AIME 2024–2025Competition mathematics · max setting100%
  • SimpleQA VerifiedShort factual questions · max setting69.7%

Scores from Epoch AI, run independently of OpenAI.

Specifications

The details

Lab
OpenAI
Released
Jul 9, 2026
Knowledge cutoff
Feb 16, 2026
Context window
1,050,000 tokens
Max output
128,000 tokens
Inputs
Text, Images, PDFs
Output
Text
Reasoning
Adjustable effort low · medium · high · xhigh · max
Tool calling
Yes
Structured output
Yes
Weights
Proprietary
API model ID
gpt-5.6-solon OpenAI
Availability
40 API providerslisted on models.dev

OpenAI model documentation

Lab-reported

What OpenAI claims

Published by the lab at launch. Settings vary, so compare these only with care.

BenchmarkScoreSettingSource
SWE-Bench Pro64.6 resolve rate—Source
Terminal-Bench v2.188.8 success rate—Source
DeepSWE v1.172.7 resolve rate—Source
GPQA Diamond94.6—Source
FrontierMath vv289—Source
BrowseComp90.4—Source
OSWorld v2.062.6 success rate—Source
MMMU Pro83no toolsSource
Agents' Last Exam52.7—Source
Toolathlon58 success rate—Source
Artificial Analysis Intelligence Index v4.158.9maxSource
Artificial Analysis Coding Agent Index v1.180maxSource
Same lab

More from OpenAI

Questions

About GPT-5.6 Sol

How much does GPT-5.6 Sol cost?

GPT-5.6 Sol costs $4.00 input / $20.00 output per million tokens (official OpenAI API price). Cached input is $0.40 per million tokens, and writing to the cache costs $5.00. Requests over 272K tokens are billed at $8.00 input / $30.00 output. At a 3:1 input-to-output mix that is $8.00 per million tokens, more expensive than 92% of the 360 priced models we track.

What is the context window of GPT-5.6 Sol?

GPT-5.6 Sol accepts up to 1,050,000 tokens per request and can write up to 128,000 tokens in one response.

How good is GPT-5.6 Sol?

Epoch AI gives GPT-5.6 Sol a Capabilities Index score of 161.8 (likely range 159.3–165.3), ranking it #8 of 148 models Epoch has scored. Epoch AI benchmark results: GPQA Diamond 93.5%, FrontierMath Tiers 1–3 89.1%, OTIS Mock AIME 2024–2025 100%, SimpleQA Verified 69.7%.

Is GPT-5.6 Sol open source?

No. GPT-5.6 Sol is proprietary; you use it through OpenAI’s API or partner platforms.

What inputs does GPT-5.6 Sol support?

GPT-5.6 Sol accepts text, images and PDFs and replies in text. It is a reasoning model with low, medium, high, xhigh and max effort settings, supports tool calling and can return structured JSON output.

When was GPT-5.6 Sol released?

OpenAI released GPT-5.6 Sol on Jul 9, 2026. Its training data runs to Feb 16, 2026.

What are the best alternatives to GPT-5.6 Sol?

The closest current models from other labs on capability, price and release date are Claude Opus 5 (Anthropic, ECI 162.9, $5.00 / $25.00), Kimi K3 (Moonshot AI, ECI 157.6, $3.00 / $15.00), Grok 4.7 (xAI, $2.00 / $6.00) and Qwen3.8 Max (Alibaba (Qwen), ECI 156.6, $2.00 / $6.00).