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Comparison · 2 models · Updated Oct 4, 2026

Grok 4.3 vs GPT-5.6 Sol

Too close to call on our weighted score (Grok 4.3 67, GPT-5.6 Sol 66). The right pick depends on what you value most.

  1. xAI

    Grok 4.3

    Released Apr 17, 2026

    67/100
    • ECI149.2
    • Price$1.25 / $2.50
    • Context1M
    Full specs Remove Grok 4.3

  2. 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

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Too close to call

It is close. Our weighted score puts them within a point (Grok 4.3 67/100, GPT-5.6 Sol 66/100), so choose by what matters most for your work: GPT-5.6 Sol for raw capability and Grok 4.3 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 · Grok 4.3 149.2
  • Lowest priceGrok 4.3Grok 4.3 $1.56 · GPT-5.6 Sol $8.00 per 1M tokens (3:1 blend)
  • Longest contextGPT-5.6 SolGPT-5.6 Sol 1,050,000 · Grok 4.3 1,000,000 tokens
  • Widest inputsSame inputsGrok 4.3: Text, Images, PDFs · GPT-5.6 Sol: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGrok 4.3GPT-5.6 Sol
CapabilityCapabilities Index (ECI)50%7793
Price25%417
Inputs & features15%8080
Context window10%6061
Overall100%67/10066/100
02 — Side by side

Every spec in one table

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

Grok 4.3 vs GPT-5.6 Sol specifications side by side
SpecificationGrok 4.3xAIGPT-5.6 SolOpenAI
Capability
Capabilities Index (ECI)149.2161.8 (best)
ECI rank#55 of 148#8 of 148 (best)
GPQA DiamondGraduate-level science questions88.8%93.5% (best)
FrontierMath Tiers 1–3Research-level mathematics42.8%89.1% (best)
OTIS Mock AIME 2024–2025Competition mathematics93.3%100% (best)
SimpleQA VerifiedShort factual questions33.2%69.7% (best)
Price per million tokens
Input$1.25 (best)$4.00
Output$2.50 (best)$20.00
Cached input$0.20 (best)$0.40
Blended (3:1)$1.56 (best)$8.00
Long-context rateOver 200K: $2.50 / $5.00Over 272K: $8.00 / $30.00
Price sourceOfficial xAI APIOfficial OpenAI API
Limits
Context window1,000,000 tokens1,050,000 tokens (best)
Max output30,000 tokens128,000 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · highYeslow · medium · high · xhigh · max
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgrok-4.3gpt-5.6-sol
API providers2740 (best)
ReleasedApr 17, 2026Jul 9, 2026
Knowledge cutoff—Feb 16, 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.

  • Grok 4.3$17.50
  • GPT-5.6 Sol$80.00
04 — Questions

Which should you choose?

Which is better: Grok 4.3 or GPT-5.6 Sol?

It is close. Our weighted score puts them within a point (Grok 4.3 67/100, GPT-5.6 Sol 66/100), so choose by what matters most for your work: GPT-5.6 Sol for raw capability and Grok 4.3 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Grok 4.3 or GPT-5.6 Sol?

Grok 4.3 is cheaper at $1.25 input / $2.50 output per million tokens (official xAI 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 $1.56 per million tokens for Grok 4.3 versus $8.00 for GPT-5.6 Sol (5.1× 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 Grok 4.3 149.2 (#55 of 148). Their confidence ranges do not overlap (159.3–165.3 vs 147.6–150.8), so the gap is a real one. On individual benchmarks: GPQA Diamond — GPT-5.6 Sol 93.5%, Grok 4.3 88.8%; FrontierMath Tiers 1–3 — GPT-5.6 Sol 89.1%, Grok 4.3 42.8%; OTIS Mock AIME 2024–2025 — GPT-5.6 Sol 100%, Grok 4.3 93.3%; SimpleQA Verified — GPT-5.6 Sol 69.7%, Grok 4.3 33.2%.

Which is better for coding?

There are no published SWE-bench Verified results for Grok 4.3 and 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 1,000,000 for Grok 4.3. Maximum output per response: Grok 4.3 up to 30,000, GPT-5.6 Sol up to 128,000 tokens.

Which can read images, PDFs, audio or video?

Grok 4.3 accepts text, images and PDFs; GPT-5.6 Sol accepts text, images and PDFs. They handle the same number of input types.

Are any of these open source?

No. Grok 4.3 and GPT-5.6 Sol are proprietary and only available through APIs and apps.

Which is newer?

GPT-5.6 Sol is the newest, released Jul 9, 2026. Grok 4.3 came out Apr 17, 2026. Knowledge cutoff: GPT-5.6 Sol Feb 16, 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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