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Model comparison

Claude 3.5 Sonnet vs Grok 4.20

Updated July 29, 2026. Public scores include evidence status and uncertainty. They are not guarantees for a specific workload.

Claude 3.5 Sonnet

Anthropic

46.9/100

Estimated · Public rank #139

90% interval 35.4–58.4

Grok 4.20

xAI

53.9/100

Estimated · Public rank #93

90% interval 37.1–70.6

Grok 4.20 has the higher public score estimate, 53.88 versus 46.9, but the 90% score intervals overlap. Treat that as a lead, not a settled winner.

1 results are shared. Category rows based on different benchmark sets are marked directional and do not name a winner.

Which one for your work

Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.

  • Long documents

    Prompts that approach the documented context limit

    Grok 4.20

    Grok 4.20 has the larger documented context window.

    Confidence: documented

  • Chat turn cost

    1K fresh input + 500 output tokens

    Grok 4.20

    Grok 4.20 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates

Show secondary and unsupported calls

  • Repository review cost

    50K fresh input + 3K output tokens

    Grok 4.20

    Grok 4.20 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates

  • Coding work

    Code generation, repair, and software-engineering tasks

    Not enough matched evidence

    The category averages use different weighted benchmark sets, so they are directional rather than like-for-like.

    Confidence: limited

  • Agentic work

    Tool use, computer use, and multi-step task completion

    Not enough matched evidence

    No shared weighted benchmark basis supports a winner.

    Confidence: limited

  • Cache-heavy agent loop cost

    200K cached + 20K fresh input + 10K output tokens

    Not enough matched evidence

    The page does not recommend a cost winner because at least one model cannot fit the stated workload in one request. Claude 3.5 Sonnet does not fit this workload in one request. Claude 3.5 Sonnet has no published cached-input rate, so cached tokens use its listed input rate. Grok 4.20 has no published cached-input rate, so cached tokens use its listed input rate.

    Confidence: rate-fallback

What is actually comparable

Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.

Shared results
1
Claude 3.5 Sonnet only
3
Grok 4.20 only
17
Like-for-like categories
0 / 8

1 category uses different evidence sets. Those rows remain visible for coverage context but do not name a winner.

Category results, on a stated basis

Each row states whether both averages use the same weighted benchmark set. Directional and not-comparable rows remain visible, but they never receive a winner in this template.

Coding

Directional only
Claude 3.5 Sonnet
49.0
Grok 4.20
67.1
Weighted basis
1 vs 2 rows
Reading
Directional only

Agentic

Not comparable
Claude 3.5 Sonnet
Not measured
Grok 4.20
47.1
Weighted basis
0 vs 1 rows
Reading
Not comparable

Reasoning

Not comparable
Claude 3.5 Sonnet
Not measured
Grok 4.20
53.3
Weighted basis
0 vs 1 rows
Reading
Not comparable

Knowledge

Not comparable
Claude 3.5 Sonnet
59.4
Grok 4.20
Not measured
Weighted basis
1 vs 0 rows
Reading
Not comparable

Math

Not comparable
Claude 3.5 Sonnet
1.6
Grok 4.20
Not measured
Weighted basis
2 vs 0 rows
Reading
Not comparable

Multilingual

Not comparable
Claude 3.5 Sonnet
Not measured
Grok 4.20
Not measured
Weighted basis
0 vs 0 rows
Reading
Not comparable

Multimodal

Not comparable
Claude 3.5 Sonnet
Not measured
Grok 4.20
70.1
Weighted basis
0 vs 2 rows
Reading
Not comparable

Instruction following

Not comparable
Claude 3.5 Sonnet
Not measured
Grok 4.20
Not measured
Weighted basis
0 vs 0 rows
Reading
Not comparable

Shape of the matched evidence

Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.

Too few matched category axes support a radar. The ruled list below shows only shared benchmark results; positions use each benchmark’s normalized display scale when available.

What each workload costs

Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.

Chat turn

1K fresh input + 500 output tokens

Claude 3.5 Sonnet
$0.0105
Fits in one request
Grok 4.20
$0.005
Fits in one request

Grok 4.20 has the lower modeled cost

Costs use the listed standard API rates.

Repository review

50K fresh input + 3K output tokens

Claude 3.5 Sonnet
$0.195
Fits in one request
Grok 4.20
$0.118
Fits in one request

Grok 4.20 has the lower modeled cost

Costs use the listed standard API rates.

Cache-heavy agent loop

200K cached + 20K fresh input + 10K output tokens

Claude 3.5 Sonnet
$0.81
Does not fit in one request
Cached input priced at the published list-input rate
Grok 4.20
$0.5
Fits in one request
Cached input priced at the published list-input rate

Claude 3.5 Sonnet does not fit this workload in one request. Claude 3.5 Sonnet has no published cached-input rate, so cached tokens use its listed input rate. Grok 4.20 has no published cached-input rate, so cached tokens use its listed input rate.

Specification differences

Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.

Context window

Maximum documented context; output-token limits may be lower.

Claude 3.5 Sonnet

200K

Grok 4.20

2M

API model ID

Claude 3.5 Sonnet

Not sourced

Grok 4.20

Not sourced

Cached-input rate

A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.

Claude 3.5 Sonnet

Not published

Grok 4.20

Not published

Documented inputs

Claude 3.5 Sonnet

Not sourced

Grok 4.20

Not sourced

Documented outputs

Claude 3.5 Sonnet

Not sourced

Grok 4.20

Not sourced

Provider availability

Claude 3.5 Sonnet

Not sourced

Grok 4.20

Not sourced

Reasoning profile

Claude 3.5 Sonnet

Non-Reasoning

Grok 4.20

Reasoning

Weight access

Claude 3.5 Sonnet

Proprietary

Grok 4.20

Proprietary

License

Claude 3.5 Sonnet

Proprietary

Grok 4.20

Proprietary

Release date

Claude 3.5 Sonnet

2024-06-01

Grok 4.20

2026-03-10

If you already use one of these models
Deployment change
The models list different providers, so authentication, endpoint behavior, limits, and feature support may change.
Quality signal
Grok 4.20 has the higher public score estimate, 53.88 versus 46.9, but the 90% score intervals overlap.
Workload cost
Repository review: $0.195 vs $0.118. Cache-heavy agent loop: $0.81 vs $0.5.
Context tradeoff
Grok 4.20 has the larger documented window (2M).

Run the same representative tasks against both endpoints before changing production traffic.

Benchmark evidence

The full public result ledger is available for audit without forcing a wide desktop table onto a phone.

Browse raw public benchmark evidence21 rows

Agentic

  • Terminal-Bench 2.0

    Claude 3.5 Sonnet—
    Grok 4.2047.1%
    Source

    Not directly comparable

  • DeepSearchQA

    Claude 3.5 Sonnet—
    Grok 4.2062.8%
    Source

    Not directly comparable

  • Gert Labs

    Claude 3.5 Sonnet—
    Grok 4.2038.36%
    Source

    Not directly comparable

Coding

  • SWE-bench Verified

    Claude 3.5 Sonnet49%
    Source
    Grok 4.2076.7%
    Source

    Grok 4.20 leads this result

  • LiveCodeBench Pro

    Claude 3.5 Sonnet—
    Grok 4.2074.2%
    Source

    Not directly comparable

  • SWE-bench Pro

    Claude 3.5 Sonnet—
    Grok 4.2051.8%
    Source

    Not directly comparable

  • Vibe Code Bench

    Claude 3.5 Sonnet—
    Grok 4.204.06%
    Source

    Not directly comparable

Reasoning

  • ARC-AGI-2

    Claude 3.5 Sonnet—
    Grok 4.2053.3%
    Source

    Not directly comparable

  • ARC-AGI-3

    Claude 3.5 Sonnet—
    Grok 4.200.1%
    Source

    Not directly comparable

Knowledge

  • GPQA

    Claude 3.5 Sonnet59.4%
    Source
    Grok 4.20—

    Not directly comparable

  • GPQA-D

    Claude 3.5 Sonnet—
    Grok 4.2088.5%
    Source

    Not directly comparable

  • HLE w/o tools

    Claude 3.5 Sonnet—
    Grok 4.2031.6%
    Source

    Not directly comparable

  • HealthBench Hard

    Claude 3.5 Sonnet—
    Grok 4.2020.3%
    Source

    Not directly comparable

  • MedXpertQA (Text)

    Claude 3.5 Sonnet—
    Grok 4.2050.2%
    Source

    Not directly comparable

Math

  • FrontierMath v2 (Tiers 1-3)

    Claude 3.5 Sonnet2.069%
    Source
    Grok 4.20—

    Not directly comparable

  • FrontierMath v2 (Tier 4)

    Claude 3.5 Sonnet0.000%
    Source
    Grok 4.20—

    Not directly comparable

Multimodal

  • MMMU-Pro

    Claude 3.5 Sonnet—
    Grok 4.2075.2%
    Source

    Not directly comparable

  • CharXiv

    Claude 3.5 Sonnet—
    Grok 4.2060.9%
    Source

    Not directly comparable

  • ERQA

    Claude 3.5 Sonnet—
    Grok 4.2054.1%
    Source

    Not directly comparable

  • SimpleVQA

    Claude 3.5 Sonnet—
    Grok 4.2057.4%
    Source

    Not directly comparable

  • MedXpertQA (MM)

    Claude 3.5 Sonnet—
    Grok 4.2065.8%
    Source

    Not directly comparable

Frequently asked questions

Which is better, Claude 3.5 Sonnet or Grok 4.20?

Grok 4.20 has the higher public score estimate, 53.88 versus 46.9, but the 90% score intervals overlap. The higher estimate is not a decisive winner because the uncertainty ranges overlap.

Which is better for coding, Claude 3.5 Sonnet or Grok 4.20?

The current coding averages use different weighted benchmark sets, so BenchLM does not name a winner from them. Read the shared benchmark rows directly and test the models on the same task set.

Which is better for agentic tasks, Claude 3.5 Sonnet or Grok 4.20?

The published evidence does not provide a shared weighted agentic tasks basis for both models, so BenchLM does not name a agentic tasks winner.

Which costs less, Claude 3.5 Sonnet or Grok 4.20?

For the stated presets, chat costs $0.0105 on Claude 3.5 Sonnet and $0.005 on Grok 4.20; repository review costs $0.195 and $0.118; the cache-heavy agent loop costs $0.81 and $0.5. Claude 3.5 Sonnet does not fit this workload in one request. Claude 3.5 Sonnet has no published cached-input rate, so cached tokens use its listed input rate. Grok 4.20 has no published cached-input rate, so cached tokens use its listed input rate.

Which has the larger context window, Claude 3.5 Sonnet or Grok 4.20?

Grok 4.20 has the larger documented context window: 2M, compared with 200K.

Related comparisons

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Last updated July 29, 2026

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