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BenchLM
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Gemini 3.1 Pro vs Gemini 3.5 Flash

Updated October 2, 2026. Rank says Gemini 3.1 Pro 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 3.1 Pro has the higher public point estimate, 65.09 versus 63.95. Their conditional score ranges overlap. These ranges do not establish rank confidence. 14 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

65.09/100

Estimated · Public rank #35

Conditional range 55.4–74.8

Model B
Google logo

Google

63.95/100

Supported · Public rank #41

90% interval 55.9–72.0

Shared results
14
Gemini 3.1 Pro only
15
Gemini 3.5 Flash only
13
Like-for-like categories
4 / 8
Estimated: Gemini 3.1 Pro · Supported: Gemini 3.5 Flash. 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 3.5 Flash

    Gemini 3.5 Flash has the higher public coding point estimate, 52.3 to 42.3, 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 3.5 Flash

    Gemini 3.5 Flash has the higher public agentic point estimate, 50.7 to 39.3, 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

    Gemini 3.5 Flash

    Gemini 3.5 Flash 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 3.5 Flash

    Gemini 3.5 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 3.5 Flash

    Gemini 3.5 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.

42.3Gemini 3.1 Pro52.3Gemini 3.5 Flash

Like-for-like · BenchAlign v5.8

Gemini 3.5 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.

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 3.1 Pro
39.3
Supported · #59/119
Gemini 3.5 Flash
50.7
Supported · #42/119
Basis
BenchAlign v5.8 lane · 6 vs 8 public rows
Reading
Gemini 3.5 Flash leads · intervals overlap

Coding

Like-for-like
Gemini 3.1 Pro
42.3
Supported · #61/144
Gemini 3.5 Flash
52.3
Supported · #39/144
Basis
BenchAlign v5.8 lane · 6 vs 7 public rows
Reading
Gemini 3.5 Flash leads · intervals overlap

Multimodal

Like-for-like
Gemini 3.1 Pro
80.1
#13/49
Gemini 3.5 Flash
87.8
#6/49
Basis
Provisional lane · 2 vs 2 weighted rows
Reading
Gemini 3.5 Flash leads

Knowledge

Like-for-like
Gemini 3.1 Pro
66.2
Supported · #22/171
Gemini 3.5 Flash
64.0
Supported · #30/171
Basis
BenchAlign v5.8 lane · 6 vs 4 public rows
Reading
Gemini 3.1 Pro leads · intervals overlap

Reasoning

Not comparable
Gemini 3.1 Pro
54.4
Unranked · 2 rankable rows
Gemini 3.5 Flash
62.8
#20/27
Basis
Provisional lane · 2 vs 2 weighted rows
Reading
Not comparable

Multilingual

Not comparable
Gemini 3.1 Pro
Not ranked
Gemini 3.5 Flash
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Instruction following

Not comparable
Gemini 3.1 Pro
Not ranked
Gemini 3.5 Flash
84.1
#43/125
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Math

Not comparable
Gemini 3.1 Pro
54.2
Unranked · 2 rankable rows
Gemini 3.5 Flash
55.1
Unranked · 2 rankable rows
Basis
Provisional lane · 2 vs 2 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 3.1 Pro
$0.008
Fits in one request
Gemini 3.5 Flash
$0.006
Fits in one request

Gemini 3.5 Flash has the lower modeled cost

Costs use the listed standard API rates.

Repository review

50K fresh input + 3K output tokens

Gemini 3.1 Pro
$0.136
Fits in one request
Gemini 3.5 Flash
$0.102
Fits in one request

Gemini 3.5 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 3.1 Pro
$0.2
Fits in one request
Gemini 3.5 Flash
$0.15
Fits in one request

Gemini 3.5 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 3.1 Pro

$0.2 per 1M cached input tokens

Google Gemini API pricing

Gemini 3.5 Flash

$0.15 per 1M cached input tokens

Google Gemini API pricing

Reasoning profile

Gemini 3.1 Pro

Reasoning

Gemini 3.5 Flash

Reasoning

Weight access

Gemini 3.1 Pro

Proprietary

Gemini 3.5 Flash

Proprietary

License

Gemini 3.1 Pro

Proprietary

Gemini 3.5 Flash

Proprietary

Release date

Gemini 3.1 Pro

2026-02-19

Gemini 3.5 Flash

2026-05-19

If you already use one of these models

Deployment change
Both entries list Google as the provider. Confirm endpoint, model ID, limits, and feature support before switching.
Quality signal
Gemini 3.1 Pro has the higher public point estimate, 65.09 versus 63.95. Their conditional score ranges overlap. These ranges do not establish rank confidence.
Workload cost
Repository review: $0.136 vs $0.102. Cache-heavy agent loop: $0.2 vs $0.15.
Context tradeoff
Both models list 1M.
Run the same representative tasks against both endpoints before changing production traffic.

Questions

Which is better, Gemini 3.1 Pro or Gemini 3.5 Flash?

Gemini 3.1 Pro has the higher public point estimate, 65.09 versus 63.95. 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 3.1 Pro or Gemini 3.5 Flash?

Gemini 3.5 Flash has the higher public coding point estimate, 52.3 to 42.3, with Supported evidence for both models. The conditional ranges do not establish rank confidence.

Which is better for agentic tasks, Gemini 3.1 Pro or Gemini 3.5 Flash?

Gemini 3.5 Flash has the higher public agentic tasks point estimate, 50.7 to 39.3, with Supported evidence for both models. The conditional ranges do not establish rank confidence.

Which costs less, Gemini 3.1 Pro or Gemini 3.5 Flash?

For the stated presets, chat costs $0.008 on Gemini 3.1 Pro and $0.006 on Gemini 3.5 Flash; repository review costs $0.136 and $0.102; the cache-heavy agent loop costs $0.2 and $0.15. Costs use the listed standard API rates.

Which has the larger context window, Gemini 3.1 Pro or Gemini 3.5 Flash?

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 evidence42 rows

Agentic

  • Claw-Eval

    Gemini 3.1 Pro57.8%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • DeepSearchQA

    Gemini 3.1 Pro69.7%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • τ²-bench results

    Gemini 3.1 Pro95.6%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • Gemini 3.1 Pro56.87%
    Gemini 3.5 Flash61.85%

    Gemini 3.5 Flash leads this result

  • ResearchClawBench

    Shared source
    Gemini 3.1 Pro13.3%
    Gemini 3.5 Flash18.0%

    Gemini 3.5 Flash leads this result

  • Terminal-Bench 2.1 (Vals)

    Gemini 3.1 Pro70.8%
    Source
    Gemini 3.5 Flash74.2%
    Source

    Gemini 3.5 Flash leads this result

  • Terminal-Bench 2.1

    Gemini 3.1 Pro—
    Gemini 3.5 Flash76.2%
    Source

    Not directly comparable

  • MCP Atlas

    Gemini 3.1 Pro—
    Gemini 3.5 Flash83.6%
    Source

    Not directly comparable

  • Toolathlon

    Gemini 3.1 Pro—
    Gemini 3.5 Flash56.5%
    Source

    Not directly comparable

  • OSWorld-Verified

    Gemini 3.1 Pro—
    Gemini 3.5 Flash78.4%
    Source

    Not directly comparable

  • Finance Agent v2

    Gemini 3.1 Pro—
    Gemini 3.5 Flash57.9%
    Source

    Not directly comparable

Coding

  • LiveCodeBench Pro

    Gemini 3.1 Pro82.9%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • React Native Evals

    Gemini 3.1 Pro78.9%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • Vibe Code Bench

    Shared source
    Gemini 3.1 Pro32.03%
    Gemini 3.5 Flash48.68%

    Gemini 3.5 Flash leads this result

  • LiveCodeBench (Vals)

    Gemini 3.1 Pro88.5%
    Source
    Gemini 3.5 Flash87.6%
    Source

    Gemini 3.1 Pro leads this result

  • SWE-bench (Vals)

    Gemini 3.1 Pro78.8%
    Source
    Gemini 3.5 Flash78.8%
    Source

    Tie

  • PostTrainBench v1.1

    Gemini 3.1 Pro22.0%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • Terminal-Bench 2.1

    Gemini 3.1 Pro—
    Gemini 3.5 Flash76.2%
    Source

    Not directly comparable

  • SWE-bench Pro

    Gemini 3.1 Pro—
    Gemini 3.5 Flash55.1%
    Source

    Not directly comparable

  • cursorBench31

    Gemini 3.1 Pro—
    Gemini 3.5 Flash49.8%
    Source

    Not directly comparable

  • CursorBench 3.2

    Gemini 3.1 Pro—
    Gemini 3.5 Flash48.8%
    Source

    Not directly comparable

Reasoning

  • ARC-AGI-2

    Gemini 3.1 Pro77.1%
    Source
    Gemini 3.5 Flash72.1%
    Source

    Gemini 3.1 Pro leads this result

  • ARC-AGI-3

    Gemini 3.1 Pro0.4%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • MRCRv2

    Gemini 3.1 Pro—
    Gemini 3.5 Flash77.3%
    Source

    Not directly comparable

  • MRCR 1M

    Gemini 3.1 Pro—
    Gemini 3.5 Flash26.6%
    Source

    Not directly comparable

Multimodal

  • MMMU-Pro

    Gemini 3.1 Pro83.9%
    Source
    Gemini 3.5 Flash83.6%
    Source

    Gemini 3.1 Pro leads this result

  • CharXiv

    Gemini 3.1 Pro80.2%
    Source
    Gemini 3.5 Flash84.2%
    Source

    Gemini 3.5 Flash leads this result

  • ERQA

    Gemini 3.1 Pro69.4%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • SimpleVQA

    Gemini 3.1 Pro72.4%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • ScreenSpot Pro

    Gemini 3.1 Pro84.4%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • ZeroBench

    Gemini 3.1 Pro29.0%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • MedXpertQA (MM)

    Gemini 3.1 Pro81.3%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • Blueprint-Bench 2

    Gemini 3.1 Pro—
    Gemini 3.5 Flash33.6%
    Source

    Not directly comparable

Knowledge

  • GPQA-D

    Gemini 3.1 Pro94.3%
    Source
    Gemini 3.5 Flash92.7%
    Source

    Gemini 3.1 Pro leads this result

  • HLE w/o tools

    Gemini 3.1 Pro45.4%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • HealthBench Hard

    Gemini 3.1 Pro20.6%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • MedXpertQA (Text)

    Gemini 3.1 Pro71.5%
    Source
    Gemini 3.5 Flash—

    Not directly comparable

  • GPQA Diamond (Vals)

    Gemini 3.1 Pro95.5%
    Source
    Gemini 3.5 Flash92.7%
    Source

    Gemini 3.1 Pro leads this result

  • MMLU-Pro (Vals)

    Gemini 3.1 Pro91.0%
    Source
    Gemini 3.5 Flash89.5%
    Source

    Gemini 3.1 Pro leads this result

  • HLE

    Gemini 3.1 Pro—
    Gemini 3.5 Flash40.2%
    Source

    Not directly comparable

Math

  • FrontierMath v2 (Tiers 1-3)

    Shared source
    Gemini 3.1 Pro36.900%
    Gemini 3.5 Flash38.966%

    Gemini 3.5 Flash leads this result

  • FrontierMath v2 (Tier 4)

    Shared source
    Gemini 3.1 Pro16.700%
    Gemini 3.5 Flash14.583%

    Gemini 3.1 Pro leads this result

42 public results · 14 shared

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Last updated October 2, 2026