ZMIME
Comparison · 2 models · Updated Oct 4, 2026

GPT-5.6 Sol vs GPT-5.1

GPT-5.6 Sol comes out ahead, 66 to 60 on our weighted score, though GPT-5.1 is 2.3× cheaper per token.

  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. OpenAI

    GPT-5.1

    Released Nov 13, 2025

    60/100
    • ECI149.7
    • Price$1.25 / $10.00
    • Context400K
    Full specs Remove GPT-5.1

  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 GPT-5.1 (60). It leads on capability, inputs & features and context window. GPT-5.1 wins on 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 · GPT-5.1 149.7
  • Lowest priceGPT-5.1GPT-5.1 $3.44 · GPT-5.6 Sol $8.00 per 1M tokens (3:1 blend)
  • Longest contextGPT-5.6 SolGPT-5.6 Sol 1,050,000 · GPT-5.1 400,000 tokens
  • Widest inputsGPT-5.6 SolGPT-5.6 Sol: Text, Images, PDFs · GPT-5.1: Text, Images
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGPT-5.6 SolGPT-5.1
CapabilityCapabilities Index (ECI)50%9378
Price25%724
Inputs & features15%8070
Context window10%6144
Overall100%66/10060/100
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 GPT-5.1 specifications side by side
SpecificationGPT-5.6 SolOpenAIGPT-5.1OpenAI
Capability
Capabilities Index (ECI)161.8 (best)149.7
ECI rank#8 of 148 (best)#52 of 148
GPQA DiamondGraduate-level science questions93.5% (best)87.6%
FrontierMath Tiers 1–3Research-level mathematics89.1%—
OTIS Mock AIME 2024–2025Competition mathematics100% (best)88.6%
SWE-bench VerifiedFixing real GitHub issues—68.0%
SimpleQA VerifiedShort factual questions69.7% (best)48.0%
Price per million tokens
Input$4.00$1.25 (best)
Output$20.00$10.00 (best)
Cached input$0.40$0.125 (best)
Blended (3:1)$8.00$3.44 (best)
Long-context rateOver 272K: $8.00 / $30.00Same rate
Price sourceOfficial OpenAI APIOfficial OpenAI API
Limits
Context window1,050,000 tokens (best)400,000 tokens
Max output128,000 tokens128,000 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesNo
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · high · xhigh · maxYeslow · medium · high
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgpt-5.6-solgpt-5.1
API providers40 (best)21
ReleasedJul 9, 2026Nov 13, 2025
Knowledge cutoffFeb 16, 2026Sep 30, 2024
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
  • GPT-5.1$32.50
04 — Questions

Which should you choose?

Which is better: GPT-5.6 Sol or GPT-5.1?

GPT-5.6 Sol is the better all-round choice, scoring 66/100 against GPT-5.1 (60). It leads on capability, inputs & features and context window. GPT-5.1 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT-5.6 Sol or GPT-5.1?

GPT-5.1 is cheaper at $1.25 input / $10.00 output per million tokens (official OpenAI API price). GPT-5.6 Sol costs $4.00 input / $20.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $3.44 per million tokens for GPT-5.1 versus $8.00 for GPT-5.6 Sol (2.3× 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 GPT-5.1 149.7 (#52 of 148). Their confidence ranges do not overlap (159.3–165.3 vs 148.3–151.1), so the gap is a real one. On individual benchmarks: GPQA Diamond — GPT-5.6 Sol 93.5%, GPT-5.1 87.6%; OTIS Mock AIME 2024–2025 — GPT-5.6 Sol 100%, GPT-5.1 88.6%; SimpleQA Verified — GPT-5.6 Sol 69.7%, GPT-5.1 48.0%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.6 Sol 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 400,000 for GPT-5.1. Maximum output per response: GPT-5.6 Sol up to 128,000, GPT-5.1 up to 128,000 tokens.

Which can read images, PDFs, audio or video?

GPT-5.6 Sol accepts text, images and PDFs; GPT-5.1 accepts text and images. GPT-5.6 Sol handles the widest range of inputs.

Are any of these open source?

No. GPT-5.6 Sol and GPT-5.1 are proprietary and only available through APIs and apps.

Which is newer?

GPT-5.6 Sol is the newest, released Jul 9, 2026. GPT-5.1 came out Nov 13, 2025. Knowledge cutoff: GPT-5.6 Sol Feb 16, 2026, GPT-5.1 Sep 30, 2024.

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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