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Comparison · 2 models · Updated Oct 4, 2026

Grok 4.20 (Reasoning) vs Muse Spark 1.2

Muse Spark 1.2 comes out ahead, 72 to 68 on our weighted score, though Grok 4.20 (Reasoning) is 22% cheaper per token.

  1. xAI

    Grok 4.20 (Reasoning)

    Released Mar 9, 2026

    68/100
    • ECI152.0
    • Price$1.25 / $2.50
    • Context1M
    Full specs Remove Grok 4.20 (Reasoning)
  2. Our pick

    Meta

    Muse Spark 1.2

    Released Aug 5, 2026

    72/100
    • ECI155.0
    • Price$1.25 / $4.25
    • Context1.05M
    Full specs Remove Muse Spark 1.2

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Muse Spark 1.2 is our pick

Muse Spark 1.2 is the better all-round choice, scoring 72/100 against Grok 4.20 (Reasoning) (68). It leads on capability and inputs & features. Grok 4.20 (Reasoning) wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityMuse Spark 1.2Capabilities Index (ECI): Muse Spark 1.2 155.0 · Grok 4.20 (Reasoning) 152.0
  • Lowest priceGrok 4.20 (Reasoning)Grok 4.20 (Reasoning) $1.56 · Muse Spark 1.2 $2.00 per 1M tokens (3:1 blend)
  • Longest contextMuse Spark 1.2Muse Spark 1.2 1,048,576 · Grok 4.20 (Reasoning) 1,000,000 tokens
  • Widest inputsMuse Spark 1.2Grok 4.20 (Reasoning): Text, Images, PDFs · Muse Spark 1.2: Text, Images, PDFs, Audio, Video
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGrok 4.20 (Reasoning)Muse Spark 1.2
CapabilityCapabilities Index (ECI)50%8184
Price25%4136
Inputs & features15%80100
Context window10%6061
Overall100%68/10072/100
02 — Side by side

Every spec in one table

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

Grok 4.20 (Reasoning) vs Muse Spark 1.2 specifications side by side
SpecificationGrok 4.20 (Reasoning)xAIMuse Spark 1.2Meta
Capability
Capabilities Index (ECI)152.0155.0 (best)
ECI rank#41 of 148#30 of 148 (best)
GPQA DiamondGraduate-level science questions89.3%—
FrontierMath Tiers 1–3Research-level mathematics44.9%—
OTIS Mock AIME 2024–2025Competition mathematics92.2%—
SimpleQA VerifiedShort factual questions30.2%60.3% (best)
Price per million tokens
Input$1.25$1.25
Output$2.50 (best)$4.25
Cached input$0.20$0.15 (best)
Blended (3:1)$1.56 (best)$2.00
Long-context rateOver 200K: $2.50 / $5.00Same rate
Price sourceOfficial xAI APIOfficial Meta API
Limits
Context window1,000,000 tokens1,048,576 tokens (best)
Max output30,000 tokens131,072 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioNoYes
VideoNoYes
ReasoningYesYesminimal · low · medium · high · xhigh
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgrok-4.20-0309-reasoningmuse-spark-1.2
API providers1115 (best)
ReleasedMar 9, 2026Aug 5, 2026
Knowledge cutoff——
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 4.20 (Reasoning)$17.50
  • Muse Spark 1.2$21.00
04 — Questions

Which should you choose?

Which is better: Grok 4.20 (Reasoning) or Muse Spark 1.2?

Muse Spark 1.2 is the better all-round choice, scoring 72/100 against Grok 4.20 (Reasoning) (68). It leads on capability and inputs & features. Grok 4.20 (Reasoning) wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Grok 4.20 (Reasoning) or Muse Spark 1.2?

Grok 4.20 (Reasoning) is cheaper at $1.25 input / $2.50 output per million tokens (official xAI API price). Muse Spark 1.2 costs $1.25 input / $4.25 output per million tokens (official Meta API price). At a typical mix of three input tokens to one output token, that is $1.56 per million tokens for Grok 4.20 (Reasoning) versus $2.00 for Muse Spark 1.2 (1.3× as much).

Which scores higher on benchmarks?

Muse Spark 1.2 scores higher on the Capabilities Index (ECI): Muse Spark 1.2 155.0 (#30 of 148) and Grok 4.20 (Reasoning) 152.0 (#41 of 148). The confidence ranges of the top two overlap (152.8–157.5 vs 149.3–154.4), so treat the gap as small. On individual benchmarks: SimpleQA Verified — Muse Spark 1.2 60.3%, Grok 4.20 (Reasoning) 30.2%.

Which is better for coding?

There are no published SWE-bench Verified results for Grok 4.20 (Reasoning) and Muse Spark 1.2 yet, so there is no like-for-like coding score. On overall capability, Muse Spark 1.2 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?

Muse Spark 1.2 has the largest context window at 1,048,576 tokens, against 1,000,000 for Grok 4.20 (Reasoning). Maximum output per response: Grok 4.20 (Reasoning) up to 30,000, Muse Spark 1.2 up to 131,072 tokens.

Which can read images, PDFs, audio or video?

Grok 4.20 (Reasoning) accepts text, images and PDFs; Muse Spark 1.2 accepts text, images, PDFs, audio and video. Muse Spark 1.2 handles the widest range of inputs.

Are any of these open source?

No. Grok 4.20 (Reasoning) and Muse Spark 1.2 are proprietary and only available through APIs and apps.

Which is newer?

Muse Spark 1.2 is the newest, released Aug 5, 2026. Grok 4.20 (Reasoning) came out Mar 9, 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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