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Comparison · 2 models · Updated Oct 4, 2026

DeepSeek-V3.1 vs Grok 4.20 (Reasoning)

Grok 4.20 (Reasoning) comes out ahead, 68 to 55 on our weighted score, though DeepSeek-V3.1 is 2.6× cheaper per token.

  1. DeepSeek

    DeepSeek-V3.1

    Released Aug 21, 2025

    55/100
    • ECI139.9
    • Price$0.385 / $1.25
    • Context131K
    Full specs Remove DeepSeek-V3.1
  2. Our pick

    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)

  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 68/100 against DeepSeek-V3.1 (55). It leads on capability, inputs & features and context window. DeepSeek-V3.1 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGrok 4.20 (Reasoning)Capabilities Index (ECI): Grok 4.20 (Reasoning) 152.0 · DeepSeek-V3.1 139.9
  • Lowest priceDeepSeek-V3.1DeepSeek-V3.1 $0.601 · Grok 4.20 (Reasoning) $1.56 per 1M tokens (3:1 blend)
  • Longest contextGrok 4.20 (Reasoning)Grok 4.20 (Reasoning) 1,000,000 · DeepSeek-V3.1 131,072 tokens
  • Widest inputsGrok 4.20 (Reasoning)DeepSeek-V3.1: Text · Grok 4.20 (Reasoning): Text, Images, PDFs
  • Self-hostingDeepSeek-V3.1Publishes downloadable weights (MIT License)
How the score is built
MeasureWeightDeepSeek-V3.1Grok 4.20 (Reasoning)
CapabilityCapabilities Index (ECI)50%6581
Price25%6041
Inputs & features15%3580
Context window10%2460
Overall100%55/10068/100
02 — Side by side

Every spec in one table

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

DeepSeek-V3.1 vs Grok 4.20 (Reasoning) specifications side by side
SpecificationDeepSeek-V3.1DeepSeekGrok 4.20 (Reasoning)xAI
Capability
Capabilities Index (ECI)139.9152.0 (best)
ECI rank#100 of 148#41 of 148 (best)
GPQA DiamondGraduate-level science questions—89.3%
FrontierMath Tiers 1–3Research-level mathematics—44.9%
OTIS Mock AIME 2024–2025Competition mathematics—92.2%
SimpleQA VerifiedShort factual questions—30.2%
Price per million tokens
Input$0.385 (best)$1.25
Output$1.25 (best)$2.50
Cached input—$0.20
Blended (3:1)$0.601 (best)$1.56
Long-context rateSame rateOver 200K: $2.50 / $5.00
Price sourceMedian of 8 providersOfficial xAI API
Limits
Context window131,072 tokens1,000,000 tokens (best)
Max output8,192 tokens30,000 tokens (best)
Inputs and features
TextYesYes
ImagesNoYes
PDFsNoYes
AudioNoNo
VideoNoNo
ReasoningYesYes
Tool callingYesYes
Structured outputNoYes
Availability
WeightsOpenMIT LicenseProprietary
API model ID—grok-4.20-0309-reasoning
API providers811 (best)
ReleasedAug 21, 2025Mar 9, 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.

  • DeepSeek-V3.1$6.35
  • Grok 4.20 (Reasoning)$17.50
04 — Questions

Which should you choose?

Which is better: DeepSeek-V3.1 or Grok 4.20 (Reasoning)?

Grok 4.20 (Reasoning) is the better all-round choice, scoring 68/100 against DeepSeek-V3.1 (55). It leads on capability, inputs & features and context window. DeepSeek-V3.1 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, DeepSeek-V3.1 or Grok 4.20 (Reasoning)?

DeepSeek-V3.1 is cheaper at $0.385 input / $1.25 output per million tokens (median across 8 API providers). Grok 4.20 (Reasoning) costs $1.25 input / $2.50 output per million tokens (official xAI API price). At a typical mix of three input tokens to one output token, that is $0.601 per million tokens for DeepSeek-V3.1 versus $1.56 for Grok 4.20 (Reasoning) (2.6× as much).

Which scores higher on benchmarks?

Grok 4.20 (Reasoning) scores higher on the Capabilities Index (ECI): Grok 4.20 (Reasoning) 152.0 (#41 of 148) and DeepSeek-V3.1 139.9 (#100 of 148). Their confidence ranges do not overlap (149.3–154.4 vs 136.1–143.3), so the gap is a real one.

Which is better for coding?

There are no published SWE-bench Verified results for DeepSeek-V3.1 and Grok 4.20 (Reasoning) 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?

Grok 4.20 (Reasoning) has the largest context window at 1,000,000 tokens, against 131,072 for DeepSeek-V3.1. Maximum output per response: DeepSeek-V3.1 up to 8,192, Grok 4.20 (Reasoning) up to 30,000 tokens.

Which can read images, PDFs, audio or video?

DeepSeek-V3.1 accepts text; Grok 4.20 (Reasoning) accepts text, images and PDFs. Grok 4.20 (Reasoning) handles the widest range of inputs.

Are any of these open source?

DeepSeek-V3.1 publishes its weights (MIT License) and can be self-hosted; Grok 4.20 (Reasoning) is proprietary.

Which is newer?

Grok 4.20 (Reasoning) is the newest, released Mar 9, 2026. DeepSeek-V3.1 came out Aug 21, 2025.

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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