ZMIME
Comparison · 3 models · Updated Nov 2, 2026

GPT-6.1 Sol vs Inkling Small vs Claude Sonnet 5.5

Too close to call on our weighted score (GPT-6.1 Sol 72, Claude Sonnet 5.5 72, Inkling Small 68). The right pick depends on what you value most.

  1. OpenAI

    GPT-6.1 Sol

    Released Sep 29, 2026New

    72/100
    • ECI167.8
    • Price$2.00 / $10.00
    • Context1.05M
    Full specs Remove GPT-6.1 Sol

  2. Thinking Machines

    Inkling Small

    Released Jul 30, 2026

    68/100
    • ECI150.5
    • Price$0.58 / $1.44
    • Context1.05M
    Full specs Remove Inkling Small

  3. Anthropic

    Claude Sonnet 5.5

    Released Sep 28, 2026New

    72/100
    • ECI166.7
    • Price$2.00 / $10.00
    • Context1M
    Full specs Remove Claude Sonnet 5.5
01 — Verdict

Too close to call

It is close. Our weighted score puts them within a point (GPT-6.1 Sol 72/100, Claude Sonnet 5.5 72/100, Inkling Small 68/100), so choose by what matters most for your work: GPT-6.1 Sol for raw capability and Inkling Small on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT-6.1 SolCapabilities Index (ECI): GPT-6.1 Sol 167.8 · Claude Sonnet 5.5 166.7 · Inkling Small 150.5
  • Lowest priceInkling SmallInkling Small $0.795 · GPT-6.1 Sol $4.00 · Claude Sonnet 5.5 $4.00 per 1M tokens (3:1 blend)
  • Longest contextGPT-6.1 Sol and Inkling SmallGPT-6.1 Sol 1,050,000 · Inkling Small 1,048,576 · Claude Sonnet 5.5 1,000,000 tokens
  • Widest inputsSame inputsGPT-6.1 Sol: Text, Images, PDFs · Inkling Small: Text, Images, Audio · Claude Sonnet 5.5: Text, Images, PDFs
  • Self-hostingInkling SmallPublishes downloadable weights (Apache-2.0)
How the score is built
MeasureWeightGPT-6.1 SolInkling SmallClaude Sonnet 5.5
CapabilityCapabilities Index (ECI)50%997797
Price25%205220
Inputs & features15%807080
Context window10%616160
Overall100%72/10068/10072/100
02 — Side by side

Every spec in one table

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

GPT-6.1 Sol vs Inkling Small vs Claude Sonnet 5.5 specifications side by side
SpecificationGPT-6.1 SolOpenAIInkling SmallThinking MachinesClaude Sonnet 5.5Anthropic
Capability
Capabilities Index (ECI)167.8 (best)150.5166.7
ECI rank#4 of 165 (best)#58 of 165#5 of 165
GPQA DiamondGraduate-level science questions95.4%88.5%95.6% (best)
FrontierMath Tiers 1–3Research-level mathematics93.7% (best)46.3%88.8%
OTIS Mock AIME 2024–2025Competition mathematics100% (best)90.0%100% (best)
SimpleQA VerifiedShort factual questions73.9% (best)19.1%46.5%
Price per million tokens
Input$2.00$0.58 (best)$2.00
Output$10.00$1.44 (best)$10.00
Cached input$0.10 (best)$0.116$0.10 (best)
Blended (3:1)$4.00$0.795 (best)$4.00
Long-context rateOver 272K: $4.00 / $15.00Same rateSame rate
Price sourceOfficial OpenAI APIOfficial Thinking Machines APIOfficial Anthropic API
Limits
Context window1,050,000 tokens (best)1,048,576 tokens1,000,000 tokens
Max output128,000 tokens1,048,576 tokens (best)128,000 tokens
Inputs and features
TextYesYesYes
ImagesYesYesYes
PDFsYesNoYes
AudioNoYesNo
VideoNoNoNo
ReasoningYeslow · medium · high · xhigh · maxYeslow · medium · high · xhigh · maxYeslow · medium · high · xhigh · max
Tool callingYesYesYes
Structured outputYesNoYes
Availability
WeightsProprietaryOpenApache-2.0Proprietary
API model IDgpt-6.1-solthinkingmachines/Inkling-Smallclaude-sonnet-5-5
API providers331234 (best)
ReleasedSep 29, 2026Jul 30, 2026Sep 28, 2026
Knowledge cutoffApr 30, 2026—Jun 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-6.1 Sol$40.00
  • Inkling Small$8.68
  • Claude Sonnet 5.5$40.00
04 — Questions

Which should you choose?

Which is better: GPT-6.1 Sol, Inkling Small or Claude Sonnet 5.5?

It is close. Our weighted score puts them within a point (GPT-6.1 Sol 72/100, Claude Sonnet 5.5 72/100, Inkling Small 68/100), so choose by what matters most for your work: GPT-6.1 Sol for raw capability and Inkling Small on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT-6.1 Sol, Inkling Small or Claude Sonnet 5.5?

Inkling Small is cheaper at $0.58 input / $1.44 output per million tokens (official Thinking Machines API price). GPT-6.1 Sol costs $2.00 input / $10.00 output per million tokens (official OpenAI API price); Claude Sonnet 5.5 costs $2.00 input / $10.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $0.795 per million tokens for Inkling Small versus $4.00 for GPT-6.1 Sol (5× as much) and $4.00 for Claude Sonnet 5.5 (5× as much).

Which scores higher on benchmarks?

GPT-6.1 Sol scores higher on the Capabilities Index (ECI): GPT-6.1 Sol 167.8 (#4 of 165), Claude Sonnet 5.5 166.7 (#5 of 165) and Inkling Small 150.5 (#58 of 165). The confidence ranges of the top two overlap (164.3–172.5 vs 163.6–171.3), so treat the gap as small. On individual benchmarks: GPQA Diamond — Claude Sonnet 5.5 95.6%, GPT-6.1 Sol 95.4%, Inkling Small 88.5%; FrontierMath Tiers 1–3 — GPT-6.1 Sol 93.7%, Claude Sonnet 5.5 88.8%, Inkling Small 46.3%; OTIS Mock AIME 2024–2025 — GPT-6.1 Sol 100%, Claude Sonnet 5.5 100%, Inkling Small 90.0%; SimpleQA Verified — GPT-6.1 Sol 73.9%, Claude Sonnet 5.5 46.5%, Inkling Small 19.1%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-6.1 Sol, Inkling Small and Claude Sonnet 5.5 yet, so there is no like-for-like coding score. On overall capability, GPT-6.1 Sol leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.

Which has the bigger context window?

GPT-6.1 Sol and Inkling Small have the largest context windows (1,050,000 and 1,048,576 tokens), against 1,000,000 for Claude Sonnet 5.5. Maximum output per response: GPT-6.1 Sol up to 128,000, Inkling Small up to 1,048,576, Claude Sonnet 5.5 up to 128,000 tokens.

Which can read images, PDFs, audio or video?

GPT-6.1 Sol accepts text, images and PDFs; Inkling Small accepts text, images and audio; Claude Sonnet 5.5 accepts text, images and PDFs. They handle the same number of input types.

Are any of these open source?

Inkling Small publishes its weights (Apache-2.0) and can be self-hosted; GPT-6.1 Sol and Claude Sonnet 5.5 is proprietary.

Which is newer?

GPT-6.1 Sol is the newest, released Sep 29, 2026. Claude Sonnet 5.5 came out Sep 28, 2026; Inkling Small came out Jul 30, 2026. Knowledge cutoff: GPT-6.1 Sol Apr 30, 2026, Claude Sonnet 5.5 Jun 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 Nov 2, 2026.

05 — Keep comparing

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