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Comparison · 2 models · Updated Oct 4, 2026

Grok 4.3 vs Claude Opus 5

Too close to call on our weighted score (Grok 4.3 67, Claude Opus 5 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. Anthropic

    Claude Opus 5

    Released Jul 24, 2026

    66/100
    • ECI162.9
    • Price$5.00 / $25.00
    • Context1M
    Full specs Remove Claude Opus 5

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01 — Verdict

Too close to call

It is close. Our weighted score puts them within a point (Grok 4.3 67/100, Claude Opus 5 66/100), so choose by what matters most for your work: Claude Opus 5 for raw capability and Grok 4.3 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityClaude Opus 5Capabilities Index (ECI): Claude Opus 5 162.9 · Grok 4.3 149.2
  • Lowest priceGrok 4.3Grok 4.3 $1.56 · Claude Opus 5 $10.00 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameGrok 4.3 1,000,000 · Claude Opus 5 1,000,000 tokens
  • Widest inputsSame inputsGrok 4.3: Text, Images, PDFs · Claude Opus 5: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGrok 4.3Claude Opus 5
CapabilityCapabilities Index (ECI)50%7794
Price25%412
Inputs & features15%8080
Context window10%6060
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 Claude Opus 5 specifications side by side
SpecificationGrok 4.3xAIClaude Opus 5Anthropic
Capability
Capabilities Index (ECI)149.2162.9 (best)
ECI rank#55 of 148#5 of 148 (best)
GPQA DiamondGraduate-level science questions88.8%93.9% (best)
FrontierMath Tiers 1–3Research-level mathematics42.8%85.6% (best)
OTIS Mock AIME 2024–2025Competition mathematics93.3%98.9% (best)
SimpleQA VerifiedShort factual questions33.2%59.9% (best)
Price per million tokens
Input$1.25 (best)$5.00
Output$2.50 (best)$25.00
Cached input$0.20 (best)$0.50
Blended (3:1)$1.56 (best)$10.00
Long-context rateOver 200K: $2.50 / $5.00Same rate
Price sourceOfficial xAI APIOfficial Anthropic API
Limits
Context window1,000,000 tokens1,000,000 tokens
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-4.3claude-opus-5
API providers2735 (best)
ReleasedApr 17, 2026Jul 24, 2026
Knowledge cutoff—May 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
  • Claude Opus 5$100.00
04 — Questions

Which should you choose?

Which is better: Grok 4.3 or Claude Opus 5?

It is close. Our weighted score puts them within a point (Grok 4.3 67/100, Claude Opus 5 66/100), so choose by what matters most for your work: Claude Opus 5 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 Claude Opus 5?

Grok 4.3 is cheaper at $1.25 input / $2.50 output per million tokens (official xAI API price). Claude Opus 5 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 $1.56 per million tokens for Grok 4.3 versus $10.00 for Claude Opus 5 (6.4× as much).

Which scores higher on benchmarks?

Claude Opus 5 scores higher on the Capabilities Index (ECI): Claude Opus 5 162.9 (#5 of 148) and Grok 4.3 149.2 (#55 of 148). Their confidence ranges do not overlap (160.2–166.7 vs 147.6–150.8), so the gap is a real one. On individual benchmarks: GPQA Diamond — Claude Opus 5 93.9%, Grok 4.3 88.8%; FrontierMath Tiers 1–3 — Claude Opus 5 85.6%, Grok 4.3 42.8%; OTIS Mock AIME 2024–2025 — Claude Opus 5 98.9%, Grok 4.3 93.3%; SimpleQA Verified — Claude Opus 5 59.9%, Grok 4.3 33.2%.

Which is better for coding?

There are no published SWE-bench Verified results for Grok 4.3 and Claude Opus 5 yet, so there is no like-for-like coding score. On overall capability, Claude Opus 5 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?

Grok 4.3 and Claude Opus 5 share the same 1,000,000-token context window. Maximum output per response: Grok 4.3 up to 30,000, Claude Opus 5 up to 128,000 tokens.

Which can read images, PDFs, audio or video?

Grok 4.3 accepts text, images and PDFs; Claude Opus 5 accepts text, images and PDFs. They handle the same number of input types.

Are any of these open source?

No. Grok 4.3 and Claude Opus 5 are proprietary and only available through APIs and apps.

Which is newer?

Claude Opus 5 is the newest, released Jul 24, 2026. Grok 4.3 came out Apr 17, 2026. Knowledge cutoff: Claude Opus 5 May 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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