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Gemini 3.8 Flash vs Grok 4.20

Updated October 17, 2026. Rank says Gemini 3.8 Flash is ahead. Price, access, and your workload can each overturn that. Public scores include evidence status and uncertainty.

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Decision reading

Gemini 3.8 Flash has the higher public point estimate, 69.25 versus 57.43. Their conditional score ranges overlap. These ranges do not establish rank confidence. 8 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.

Model A
Google logo

Google

69.25/100

Supported · Public rank #22

90% interval 63.6–74.9

Model B
xAI logo

xAI

57.43/100

Estimated · Public rank #60

Conditional range 47.7–67.2

Shared results
8
Gemini 3.8 Flash only
23
Grok 4.20 only
16
Like-for-like categories
3 / 8
Supported: Gemini 3.8 Flash · Estimated: Grok 4.20. Conditional ranges do not establish rank confidence.How the comparison works

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.

  • Coding work

    Code generation, repair, and software-engineering tasks

    Gemini 3.8 Flash

    Gemini 3.8 Flash has the higher public coding point estimate, 61 to 21.6, with Supported evidence for both models. The conditional ranges do not establish rank confidence.

    Confidence: limited
  • Agentic work

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

    Gemini 3.8 Flash

    Gemini 3.8 Flash has the higher public agentic point estimate, 65.9 to 25.1, with Supported evidence for both models. The conditional ranges do not establish rank confidence.

    Confidence: limited
  • 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
  • Cache-heavy agent loop cost

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

    Gemini 3.8 Flash

    Gemini 3.8 Flash has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates
  • Repository review cost

    50K fresh input + 3K output tokens

    Gemini 3.8 Flash

    Gemini 3.8 Flash has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates
  • Long documents

    Prompts that approach the documented context limit

    No clear pick

    The documented context windows are equal.

    Confidence: documented

Which one for a specific job

Choose a job from the LLM Selector's task catalog to see the category row it rests on, under the same basis rules as the table below. A directional row stays directional; choosing a job never creates a winner.

The same task catalog as the LLM Selector. Each job names the evidence surface it rests on; nothing here adds a new score.

61.0Gemini 3.8 Flash21.6Grok 4.20

Like-for-like · BenchAlign v5.8

Gemini 3.8 Flash has the higher coding point estimate. Conditional score ranges do not establish rank confidence.

Coding scores combine specific tasks and setups. Match the editor, harness, and effort to your workflow.

Same basis rules as the category table below

What is actually comparable

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

1 category rests on Estimated evidence or different evidence sets. Those rows remain visible for coverage context but do not name a winner.

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.

Bars run 0–100 on each benchmark’s normalized display scale

Category results, on a stated basis

Each row shows the public-lane category score for both models: the BenchAlign v5.8 lane for agentic, coding, and knowledge, and the weighted public rows elsewhere, with the same rank each model page reports. A row is like-for-like only when both scores rest on Supported evidence or the same weighted set. Directional and not-comparable rows remain visible, but they never receive a winner.

Agentic

Like-for-like
Gemini 3.8 Flash
65.9
Supported · #16/128
Grok 4.20
25.1
Supported · #103/128
Basis
BenchAlign v5.8 lane · 9 vs 5 public rows
Reading
Gemini 3.8 Flash leads

Coding

Like-for-like
Gemini 3.8 Flash
61.0
Supported · #17/150
Grok 4.20
21.6
Supported · #118/150
Basis
BenchAlign v5.8 lane · 8 vs 6 public rows
Reading
Gemini 3.8 Flash leads

Knowledge

Like-for-like
Gemini 3.8 Flash
73.5
Supported · #13/184
Grok 4.20
53.1
Supported · #69/184
Basis
BenchAlign v5.8 lane · 6 vs 6 public rows
Reading
Gemini 3.8 Flash leads · intervals overlap

Multimodal

Directional only
Gemini 3.8 Flash
87.3
#9/54
Grok 4.20
53.4
#47/54
Basis
Provisional lane · 0 vs 2 weighted rows
Reading
Directional only

Reasoning

Not comparable
Gemini 3.8 Flash
74.3
#17/28
Grok 4.20
44.9
Unranked · 2 rankable rows
Basis
Provisional lane · 2 vs 2 weighted rows
Reading
Not comparable

Multilingual

Not comparable
Gemini 3.8 Flash
Not ranked
Grok 4.20
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Instruction following

Not comparable
Gemini 3.8 Flash
Not ranked
Grok 4.20
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Math

Not comparable
Gemini 3.8 Flash
69.7
Unranked · 2 rankable rows
Grok 4.20
Not ranked
Basis
Provisional lane · 2 vs 0 weighted rows
Reading
Not comparable

Ranks count the models scored in each category’s lane, so the agentic, coding, and knowledge denominators (BenchAlign v5.8) differ from the provisional-lane categories. Unranked scores sit on the provisional lane’s scale but never name a winner. Like-for-like rows within 0.5 points read as a practical tie.

Supported evidence per lane · bars run 0–100Methodology

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

Gemini 3.8 Flash
$0.00262
Fits in one request
Grok 4.20
$0.0025
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

Gemini 3.8 Flash
$0.04875
Fits in one request
Grok 4.20
$0.07
Fits in one request

Gemini 3.8 Flash has the lower modeled cost

Costs use the listed standard API rates.

Cache-heavy agent loop

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

Gemini 3.8 Flash
$0.0675
Fits in one request
Grok 4.20
$0.09
Fits in one request

Gemini 3.8 Flash has the lower modeled cost

Costs use the listed standard API rates.

Cached input falls back to the list input rate only where a cached rate is unpublished

Specification differences

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

Cached-input rate

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

Gemini 3.8 Flash

$0.075 per 1M cached input tokens

Google Gemini API pricing

Grok 4.20

$0.2 per 1M cached input tokens

Reasoning profile

Gemini 3.8 Flash

Reasoning

Grok 4.20

Reasoning

Weight access

Gemini 3.8 Flash

Proprietary

Grok 4.20

Proprietary

License

Gemini 3.8 Flash

Proprietary

Grok 4.20

Proprietary

Release date

Gemini 3.8 Flash

2026-09-02

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
Gemini 3.8 Flash has the higher public point estimate, 69.25 versus 57.43. Their conditional score ranges overlap. These ranges do not establish rank confidence.
Workload cost
Repository review: $0.04875 vs $0.07. Cache-heavy agent loop: $0.0675 vs $0.09.
Context tradeoff
Both models list 1M.
Run the same representative tasks against both endpoints before changing production traffic.

Questions

Which is better, Gemini 3.8 Flash or Grok 4.20?

Gemini 3.8 Flash has the higher public point estimate, 69.25 versus 57.43. Their conditional score ranges overlap. These ranges do not establish rank confidence. The page therefore keeps the decision tied to the specific documented workload.

Which is better for coding, Gemini 3.8 Flash or Grok 4.20?

Gemini 3.8 Flash has the higher public coding point estimate, 61 to 21.6, with Supported evidence for both models. The conditional ranges do not establish rank confidence.

Which is better for agentic tasks, Gemini 3.8 Flash or Grok 4.20?

Gemini 3.8 Flash has the higher public agentic tasks point estimate, 65.9 to 25.1, with Supported evidence for both models. The conditional ranges do not establish rank confidence.

Which costs less, Gemini 3.8 Flash or Grok 4.20?

For the stated presets, chat costs $0.00263 on Gemini 3.8 Flash and $0.0025 on Grok 4.20; repository review costs $0.04875 and $0.07; the cache-heavy agent loop costs $0.0675 and $0.09. Costs use the listed standard API rates.

Which has the larger context window, Gemini 3.8 Flash or Grok 4.20?

Both models list the same context window, 1M.

Benchmark evidence

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

Browse raw public benchmark evidence47 rows

Agentic

  • Finance Agent v2

    Gemini 3.8 Flash61.4%
    Source
    Grok 4.20—

    Not directly comparable

  • Terminal-Bench 2.1

    Gemini 3.8 Flash89.4%
    Source
    Grok 4.20—

    Not directly comparable

  • Terminal-Bench 4.0

    Gemini 3.8 Flash19.10%
    Source
    Grok 4.20—

    Not directly comparable

  • OSWorld 2.0

    Gemini 3.8 Flash59.0%
    Source
    Grok 4.20—

    Not directly comparable

  • Terminal-Bench 2.1 (Vals)

    Gemini 3.8 Flash81.3%
    Source
    Grok 4.2044.2%
    Source

    Gemini 3.8 Flash leads this result

  • ApprenticeBench

    Gemini 3.8 Flash24%
    Source
    Grok 4.20—

    Not directly comparable

  • Hermes Index

    Gemini 3.8 Flash38.1%
    Source
    Grok 4.20—

    Not directly comparable

  • Hermes Bench

    Gemini 3.8 Flash62.2%
    Source
    Grok 4.20—

    Not directly comparable

  • MazeBench

    Gemini 3.8 Flash4%
    Source
    Grok 4.200%
    Source

    Gemini 3.8 Flash leads this result

  • Terminal-Bench 2.0

    Gemini 3.8 Flash—
    Grok 4.2047.1%
    Source

    Not directly comparable

  • DeepSearchQA

    Gemini 3.8 Flash—
    Grok 4.2062.8%
    Source

    Not directly comparable

  • Gert Labs

    Gemini 3.8 Flash—
    Grok 4.2038.36%
    Source

    Not directly comparable

Coding

  • DeepSWE

    Gemini 3.8 Flash73.8%
    Source
    Grok 4.20—

    Not directly comparable

  • Terminal-Bench 2.1

    Gemini 3.8 Flash89.4%
    Source
    Grok 4.20—

    Not directly comparable

  • CursorBench 3.2

    Gemini 3.8 Flash69.2%
    Source
    Grok 4.20—

    Not directly comparable

  • LiveCodeBench (Vals)

    Gemini 3.8 Flash89.5%
    Source
    Grok 4.2084.3%
    Source

    Gemini 3.8 Flash leads this result

  • SWE-bench (Vals)

    Gemini 3.8 Flash80.0%
    Source
    Grok 4.2072.2%
    Source

    Gemini 3.8 Flash leads this result

  • FrontierSWE v2

    Gemini 3.8 Flash19.6%
    Source
    Grok 4.20—

    Not directly comparable

  • CursorBench 4.0

    Gemini 3.8 Flash39.6%
    Source
    Grok 4.20—

    Not directly comparable

  • Bug Hunt Bench

    Gemini 3.8 Flash18.0 fixes
    Source
    Grok 4.20—

    Not directly comparable

  • LiveCodeBench Pro

    Gemini 3.8 Flash—
    Grok 4.2074.2%
    Source

    Not directly comparable

  • SWE-bench Verified

    Gemini 3.8 Flash—
    Grok 4.2076.7%
    Source

    Not directly comparable

  • SWE-bench Pro

    Gemini 3.8 Flash—
    Grok 4.2051.8%
    Source

    Not directly comparable

  • Vibe Code Bench

    Gemini 3.8 Flash—
    Grok 4.204.06%
    Source

    Not directly comparable

Reasoning

  • ARC-AGI-1

    Gemini 3.8 Flash98.50%
    Source
    Grok 4.20—

    Not directly comparable

  • ARC-AGI-2

    Gemini 3.8 Flash89.2%
    Source
    Grok 4.2053.3%
    Source

    Gemini 3.8 Flash leads this result

  • ARC-AGI-3

    Gemini 3.8 Flash10.4%
    Source
    Grok 4.200.1%
    Source

    Gemini 3.8 Flash leads this result

Multimodal

  • CharXiv w/o tools

    Gemini 3.8 Flash86.2%
    Source
    Grok 4.20—

    Not directly comparable

  • LVBench

    Gemini 3.8 Flash87.1%
    Source
    Grok 4.20—

    Not directly comparable

  • MMMU-Pro

    Gemini 3.8 Flash—
    Grok 4.2075.2%
    Source

    Not directly comparable

  • CharXiv

    Gemini 3.8 Flash—
    Grok 4.2060.9%
    Source

    Not directly comparable

  • ERQA

    Gemini 3.8 Flash—
    Grok 4.2054.1%
    Source

    Not directly comparable

  • SimpleVQA

    Gemini 3.8 Flash—
    Grok 4.2057.4%
    Source

    Not directly comparable

  • MedXpertQA (MM)

    Gemini 3.8 Flash—
    Grok 4.2065.8%
    Source

    Not directly comparable

Knowledge

  • HLE-Verified

    Gemini 3.8 Flash54.9%
    Source
    Grok 4.20—

    Not directly comparable

  • LABBench2

    Gemini 3.8 Flash86.2%
    Source
    Grok 4.20—

    Not directly comparable

  • BioMysteryBench (human-solvable)

    Gemini 3.8 Flash88.8%
    Source
    Grok 4.20—

    Not directly comparable

  • BioMysteryBench (human-difficult)

    Gemini 3.8 Flash56.5%
    Source
    Grok 4.20—

    Not directly comparable

  • GPQA Diamond (Vals)

    Gemini 3.8 Flash94.4%
    Source
    Grok 4.2088.6%
    Source

    Gemini 3.8 Flash leads this result

  • MMLU-Pro (Vals)

    Gemini 3.8 Flash90.2%
    Source
    Grok 4.2086.3%
    Source

    Gemini 3.8 Flash leads this result

  • GPQA-D

    Gemini 3.8 Flash—
    Grok 4.2088.5%
    Source

    Not directly comparable

  • HLE w/o tools

    Gemini 3.8 Flash—
    Grok 4.2031.6%
    Source

    Not directly comparable

  • HealthBench Hard

    Gemini 3.8 Flash—
    Grok 4.2020.3%
    Source

    Not directly comparable

  • MedXpertQA (Text)

    Gemini 3.8 Flash—
    Grok 4.2050.2%
    Source

    Not directly comparable

Instruction following

  • Gray Swan IPI (15 attempts)

    Gemini 3.8 Flash5.5%
    Source
    Grok 4.20—

    Not directly comparable

Math

  • FrontierMath v2 (Tiers 1-3)

    Gemini 3.8 Flash68.421%
    Source
    Grok 4.20—

    Not directly comparable

  • FrontierMath v2 (Tier 4)

    Gemini 3.8 Flash21.951%
    Source
    Grok 4.20—

    Not directly comparable

47 public results · 8 shared

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Last updated October 17, 2026