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Comparison · 2 models · Updated Nov 2, 2026

Grok 4.20 (Reasoning) vs Inkling

Grok 4.20 (Reasoning) comes out ahead, 67 to 63 on our weighted score, and it is the cheaper option too.

  1. Our pick

    xAI

    Grok 4.20 (Reasoning)

    Released Mar 9, 2026

    67/100
    • ECI152.3
    • Price$1.25 / $2.50
    • Context1M
    Full specs Remove Grok 4.20 (Reasoning)

  2. Thinking Machines

    Inkling

    Released Jul 15, 2026

    63/100
    • ECI148.5
    • Price$1.00 / $4.05
    • Context1.05M
    Full specs Remove Inkling

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Grok 4.20 (Reasoning) is our pick

Grok 4.20 (Reasoning) is the better all-round choice, scoring 67/100 against Inkling (63). It leads on capability, price and inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGrok 4.20 (Reasoning)Capabilities Index (ECI): Grok 4.20 (Reasoning) 152.3 · Inkling 148.5
  • Lowest priceGrok 4.20 (Reasoning)Grok 4.20 (Reasoning) $1.56 · Inkling $1.76 per 1M tokens (3:1 blend)
  • Longest contextInklingInkling 1,048,576 · Grok 4.20 (Reasoning) 1,000,000 tokens
  • Widest inputsSame inputsGrok 4.20 (Reasoning): Text, Images, PDFs · Inkling: Text, Images, Audio
  • Self-hostingInklingPublishes downloadable weights (Apache-2.0)
How the score is built
MeasureWeightGrok 4.20 (Reasoning)Inkling
CapabilityCapabilities Index (ECI)50%7975
Price25%3937
Inputs & features15%8070
Context window10%6061
Overall100%67/10063/100
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 Inkling specifications side by side
SpecificationGrok 4.20 (Reasoning)xAIInklingThinking Machines
Capability
Capabilities Index (ECI)152.3 (best)148.5
ECI rank#51 of 165 (best)#67 of 165
GPQA DiamondGraduate-level science questions89.3% (best)88.3%
FrontierMath Tiers 1–3Research-level mathematics44.9% (best)33.3%
OTIS Mock AIME 2024–2025Competition mathematics92.2% (best)88.9%
SimpleQA VerifiedShort factual questions30.2%40.3% (best)
Price per million tokens
Input$1.25$1.00 (best)
Output$2.50 (best)$4.05
Cached input$0.20$0.17 (best)
Blended (3:1)$1.56 (best)$1.76
Long-context rateOver 200K: $2.50 / $5.00Same rate
Price sourceOfficial xAI APIOfficial Thinking Machines API
Limits
Context window1,000,000 tokens1,048,576 tokens (best)
Max output30,000 tokens1,048,576 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesNo
AudioNoYes
VideoNoNo
ReasoningYesYeslow · medium · high · xhigh · max
Tool callingYesYes
Structured outputYesNo
Availability
WeightsProprietaryOpenApache-2.0
API model IDgrok-4.20-0309-reasoningthinkingmachines/Inkling:peft:262144:sampling-nvfp4
API providers1520 (best)
ReleasedMar 9, 2026Jul 15, 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
  • Inkling$18.10
04 — Questions

Which should you choose?

Which is better: Grok 4.20 (Reasoning) or Inkling?

Grok 4.20 (Reasoning) is the better all-round choice, scoring 67/100 against Inkling (63). It leads on capability, price and inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Grok 4.20 (Reasoning) or Inkling?

Grok 4.20 (Reasoning) is cheaper at $1.25 input / $2.50 output per million tokens (official xAI API price). Inkling costs $1.00 input / $4.05 output per million tokens (official Thinking Machines 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 $1.76 for Inkling (1.1× as much).

Which scores higher on benchmarks?

Grok 4.20 (Reasoning) scores higher on the Capabilities Index (ECI): Grok 4.20 (Reasoning) 152.3 (#51 of 165) and Inkling 148.5 (#67 of 165). The confidence ranges of the top two overlap (149.5–154.7 vs 145.8–150.4), so treat the gap as small. On individual benchmarks: GPQA Diamond — Grok 4.20 (Reasoning) 89.3%, Inkling 88.3%; FrontierMath Tiers 1–3 — Grok 4.20 (Reasoning) 44.9%, Inkling 33.3%; OTIS Mock AIME 2024–2025 — Grok 4.20 (Reasoning) 92.2%, Inkling 88.9%; SimpleQA Verified — Inkling 40.3%, 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 Inkling yet, so there is no like-for-like coding score. On overall capability, Grok 4.20 (Reasoning) 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?

Inkling 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, Inkling up to 1,048,576 tokens.

Which can read images, PDFs, audio or video?

Grok 4.20 (Reasoning) accepts text, images and PDFs; Inkling accepts text, images and audio. They handle the same number of input types.

Are any of these open source?

Inkling publishes its weights (Apache-2.0) and can be self-hosted; Grok 4.20 (Reasoning) is proprietary.

Which is newer?

Inkling is the newest, released Jul 15, 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 Nov 2, 2026.

05 — Keep comparing

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