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Comparison · 2 models · Updated Oct 4, 2026

GPT-5.6 Sol vs Claude Opus 4.8

GPT-5.6 Sol comes out ahead, 66 to 63 on our weighted score, and it is the cheaper option too.

  1. Our pick

    OpenAI

    GPT-5.6 Sol

    Released Jul 9, 2026

    66/100
    • ECI161.8
    • Price$4.00 / $20.00
    • Context1.05M
    Full specs Remove GPT-5.6 Sol

  2. Anthropic

    Claude Opus 4.8

    Released May 28, 2026

    63/100
    • ECI158.3
    • Price$5.00 / $25.00
    • Context1M
    Full specs Remove Claude Opus 4.8

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT-5.6 Sol is our pick

GPT-5.6 Sol is the better all-round choice, scoring 66/100 against Claude Opus 4.8 (63). It leads on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT-5.6 SolCapabilities Index (ECI): GPT-5.6 Sol 161.8 · Claude Opus 4.8 158.3
  • Lowest priceGPT-5.6 SolGPT-5.6 Sol $8.00 · Claude Opus 4.8 $10.00 per 1M tokens (3:1 blend)
  • Longest contextGPT-5.6 SolGPT-5.6 Sol 1,050,000 · Claude Opus 4.8 1,000,000 tokens
  • Widest inputsSame inputsGPT-5.6 Sol: Text, Images, PDFs · Claude Opus 4.8: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGPT-5.6 SolClaude Opus 4.8
CapabilityCapabilities Index (ECI)50%9389
Price25%72
Inputs & features15%8080
Context window10%6160
Overall100%66/10063/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

GPT-5.6 Sol vs Claude Opus 4.8 specifications side by side
SpecificationGPT-5.6 SolOpenAIClaude Opus 4.8Anthropic
Capability
Capabilities Index (ECI)161.8 (best)158.3
ECI rank#8 of 148 (best)#12 of 148
GPQA DiamondGraduate-level science questions93.5% (best)91.0%
FrontierMath Tiers 1–3Research-level mathematics89.1% (best)80.0%
OTIS Mock AIME 2024–2025Competition mathematics100% (best)98.3%
SimpleQA VerifiedShort factual questions69.7% (best)53.0%
Price per million tokens
Input$4.00 (best)$5.00
Output$20.00 (best)$25.00
Cached input$0.40 (best)$0.50
Blended (3:1)$8.00 (best)$10.00
Long-context rateOver 272K: $8.00 / $30.00Same rate
Price sourceOfficial OpenAI APIOfficial Anthropic API
Limits
Context window1,050,000 tokens (best)1,000,000 tokens
Max output128,000 tokens128,000 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · high · xhigh · maxYeslow · medium · high · xhigh · max
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgpt-5.6-solclaude-opus-4-8
API providers4045 (best)
ReleasedJul 9, 2026May 28, 2026
Knowledge cutoffFeb 16, 2026Jan 2026
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • GPT-5.6 Sol$80.00
  • Claude Opus 4.8$100.00
04 — Questions

Which should you choose?

Which is better: GPT-5.6 Sol or Claude Opus 4.8?

GPT-5.6 Sol is the better all-round choice, scoring 66/100 against Claude Opus 4.8 (63). It leads on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT-5.6 Sol or Claude Opus 4.8?

GPT-5.6 Sol is cheaper at $4.00 input / $20.00 output per million tokens (official OpenAI API price). Claude Opus 4.8 costs $5.00 input / $25.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $8.00 per million tokens for GPT-5.6 Sol versus $10.00 for Claude Opus 4.8 (1.3× as much).

Which scores higher on benchmarks?

GPT-5.6 Sol scores higher on the Capabilities Index (ECI): GPT-5.6 Sol 161.8 (#8 of 148) and Claude Opus 4.8 158.3 (#12 of 148). The confidence ranges of the top two overlap (159.3–165.3 vs 156.1–160.7), so treat the gap as small. On individual benchmarks: GPQA Diamond — GPT-5.6 Sol 93.5%, Claude Opus 4.8 91.0%; FrontierMath Tiers 1–3 — GPT-5.6 Sol 89.1%, Claude Opus 4.8 80.0%; OTIS Mock AIME 2024–2025 — GPT-5.6 Sol 100%, Claude Opus 4.8 98.3%; SimpleQA Verified — GPT-5.6 Sol 69.7%, Claude Opus 4.8 53.0%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.6 Sol and Claude Opus 4.8 yet, so there is no like-for-like coding score. On overall capability, GPT-5.6 Sol leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Which has the bigger context window?

GPT-5.6 Sol has the largest context window at 1,050,000 tokens, against 1,000,000 for Claude Opus 4.8. Maximum output per response: GPT-5.6 Sol up to 128,000, Claude Opus 4.8 up to 128,000 tokens.

Which can read images, PDFs, audio or video?

GPT-5.6 Sol accepts text, images and PDFs; Claude Opus 4.8 accepts text, images and PDFs. They handle the same number of input types.

Are any of these open source?

No. GPT-5.6 Sol and Claude Opus 4.8 are proprietary and only available through APIs and apps.

Which is newer?

GPT-5.6 Sol is the newest, released Jul 9, 2026. Claude Opus 4.8 came out May 28, 2026. Knowledge cutoff: GPT-5.6 Sol Feb 16, 2026, Claude Opus 4.8 Jan 2026.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.

05 — Keep comparing

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