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Head-to-head comparison

Gemini 3.8 Flash vs. Gemini 3.1 Pro Preview

Compare published benchmark results from matching versions and cohorts, API pricing, and technical specifications. Any documented test setup differences remain visible.

shared result series
23
distinct benchmarks
23
latest retrieval
2026-09-02

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Specifications

General specifications

Release date, availability, context window, architecture, and published parameter counts at a glance. Undisclosed details remain marked as unavailable.

Specifications for Gemini 3.8 Flash and Gemini 3.1 Pro Preview
AttributeGemini 3.8 FlashGemini 3.1 Pro Preview
ProviderGoogleGoogle
ReleasedSep 2, 2026Feb 19, 2026
AvailabilityActivePreview
Model typeProprietaryProprietary
ParametersNot publishedNot published
ArchitectureNot publishedNot published
Context window1,048,576 tokens1,048,576 tokens
Knowledge cutoffMarch 2026Not published
Technical sourcesModel, Knowledge cutoffModel

Pricing

API pricing compared

The table compares official standard API rates per 1M tokens, including published cache pricing. Batch, fast, priority, regional surcharges, tool calls, and cloud platform pricing are excluded.

API pricing for Gemini 3.8 Flash and Gemini 3.1 Pro Preview
Price typeGemini 3.8 FlashGemini 3.1 Pro Preview
API input$0.75$2 ≤200K / $4 >200K
API output$3.75$12 ≤200K / $18 >200K
Cache read$0.07$0.2 ≤200K / $0.4 >200K
Cache write (5 min.)Not listedNot listed
Cache write (1 hr.)Not listedNot listed
Price verified09/02/2026 Source07/30/2026 Source
Gemini 3.8 FlashGemini 3.1 Pro Preview
API inputUSD per 1M tokens, base tier
Gemini 3.8 FlashLower price$0.75
Gemini 3.1 Pro Preview$2
API outputUSD per 1M tokens, base tier
Gemini 3.8 FlashLower price$3.75
Gemini 3.1 Pro Preview$12
Cache readUSD per 1M tokens, base tier
Gemini 3.8 FlashLower price$0.075
Gemini 3.1 Pro Preview$0.2

Key to the marks:better valuebetter, but not conclusivetie

Pricing by provider

Direct developer pricing and provider endpoint tariffs routed through OpenRouter are listed separately. Prices are in USD per 1M tokens. Context-dependent direct tiers plus regional, Flex, Priority, and other OpenRouter tariffs remain individually identifiable.

Provider pricing for Gemini 3.8 Flash and Gemini 3.1 Pro Preview
ModelProviderPurchase route and tariffInput per 1M tokensOutput per 1M tokensSource
Gemini 3.8 FlashGoogleDirect from developerStandard API$0.75$3.75Source09/02/2026
GoogleVia OpenRoutergoogle-vertex/global$0.75$3.75Source09/02/2026
GoogleVia OpenRoutergoogle-vertex/global/flexLowest listed price: $0.375Lowest listed price: $1.875Source09/02/2026
GoogleVia OpenRoutergoogle-vertex/global/priority$1.35$6.75Source09/02/2026
Google AI StudioVia OpenRoutergoogle-ai-studio$0.75$3.75Source09/02/2026
Google AI StudioVia OpenRoutergoogle-ai-studio/flexLowest listed price: $0.375Lowest listed price: $1.875Source09/02/2026
Google AI StudioVia OpenRoutergoogle-ai-studio/priority$1.35$6.75Source09/02/2026
Gemini 3.1 Pro PreviewGoogleDirect from developerUp to 200,000 context tokens$2$12Source07/30/2026
GoogleDirect from developerAbove 200,000 context tokens$4$18Source07/30/2026
GoogleVia OpenRoutergoogle-vertex/global$2$12Source09/02/2026
GoogleVia OpenRoutergoogle-vertex/global/flexLowest listed price: $1Lowest listed price: $6Source09/02/2026
GoogleVia OpenRoutergoogle-vertex/global/priority$3.6$21.6Source09/02/2026
Google AI StudioVia OpenRoutergoogle-ai-studio$2$12Source09/02/2026
Google AI StudioVia OpenRoutergoogle-ai-studio/flexLowest listed price: $1Lowest listed price: $6Source09/02/2026
Google AI StudioVia OpenRoutergoogle-ai-studio/priority$3.6$21.6Source09/02/2026

Performance

Shared benchmarks

Only published results with the same benchmark version, task, metric, and comparison cohort are paired. Different reasoning levels, agents, harnesses, or output limits appear directly in the table.

Capability profile from matched benchmarks

Each axis averages directly matched benchmark families. A value of 100 means the stronger value within this pair, not a universal quality score.

255075100CodingReasoningMathematicsKnowledgeFinanceLegalAgentic tasksMultimodal
Gemini 3.8 Flash
Gemini 3.1 Pro Preview
Coding: 100 / 57.1 (5 benchmark families)
Reasoning: 98.9 / 100 (1 benchmark family)
Mathematics: 100 / 54.2 (1 benchmark family)
Knowledge: 99.2 / 100 (1 benchmark family)
Finance: 98.5 / 85.2 (4 benchmark families)
Legal: 99.8 / 51 (3 benchmark families)
Agentic tasks: 100 / 87.1 (1 benchmark family)
Multimodal: 100 / 99 (1 benchmark family)

23 matched rows from 23 benchmark families were considered. The radar shows 8 of 13 comparable categories.

Gemini 3.8 FlashGemini 3.1 Pro Preview
Code MigrationOverall. Higher is better. No documented setup difference
Gemini 3.8 FlashWinner36.546 %
Gemini 3.1 Pro Preview17.313 %
CyberBenchOverall. Higher is better. No documented setup difference
Gemini 3.8 FlashWinner43.75 %
Gemini 3.1 Pro Preview36.441 %
EMBOverall. Higher is better. No documented setup difference
Gemini 3.8 FlashWinner72.196 %
Gemini 3.1 Pro Preview52.616 %
Finance Agent (v2)Overall. Higher is better. No documented setup difference
Gemini 3.8 FlashWinner61.435 %
Gemini 3.1 Pro Preview42.982 %
GPQA DiamondOverall. Higher is better. No documented setup difference
Gemini 3.8 Flash94.444 %
Gemini 3.1 Pro PreviewWinner95.454 %
Harvey's Legal Agent BenchmarkOverall · Task fully resolved. Higher is better. No documented setup difference
Gemini 3.8 FlashWinner10 %
Gemini 3.1 Pro Preview0 %
Legal Research BenchOverall · All-pass. Higher is better. No documented setup difference
Gemini 3.8 FlashWinner38.942 %
Gemini 3.1 Pro Preview20.673 %
LegalBenchOverall. Higher is better. No documented setup difference
Gemini 3.8 Flash86.993 %
Gemini 3.1 Pro PreviewWinner87.398 %
LiveCodeBench v6Overall. Higher is better. No documented setup difference
Gemini 3.8 FlashWinner89.484 %
Gemini 3.1 Pro Preview88.485 %
MedCodeOverall. Higher is better. No documented setup difference
Gemini 3.8 Flash48.135 %
Gemini 3.1 Pro PreviewWinner59.062 %
MedScribeOverall. Higher is better. No documented setup difference
Gemini 3.8 FlashWinner84.496 %
Gemini 3.1 Pro Preview76.114 %
MMLU-ProOverall. Higher is better. No documented setup difference
Gemini 3.8 Flash90.221 %
Gemini 3.1 Pro PreviewWinner90.987 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for Gemini 3.8 Flash and Gemini 3.1 Pro Preview
Benchmark and taskGemini 3.8 FlashGemini 3.1 Pro PreviewSource
Code MigrationOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner36.546 %
17.313 %
Vals AI
Source details
Data as of: 09/01/2026
CyberBenchOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner43.75 %
36.441 %
Vals AI
Source details
Data as of: 09/01/2026
EMBOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner72.196 %
52.616 %
Vals AI
Source details
Data as of: 09/01/2026
Finance Agent (v2)Overall
Test details
No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better
Winner61.435 %
42.982 %
Vals AI
Source details
Data as of: 09/01/2026
GPQA DiamondOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
94.444 %
Winner95.454 %
Vals AI
Source details
Data as of: 09/01/2026
Harvey's Legal Agent BenchmarkOverall · Task fully resolved
Test details
No documented difference in the test setupVersion: 1Metric: task resolution rateScoring: Higher is better
Winner10 %
0 %
Vals AI
Source details
Data as of: 09/01/2026
Legal Research BenchOverall · All-pass
Test details
No documented difference in the test setupVersion: 1Metric: all-pass rateScoring: Higher is better
Winner38.942 %
20.673 %
Vals AI
Source details
Data as of: 09/01/2026
LegalBenchOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
86.993 %
Winner87.398 %
Vals AI
Source details
Data as of: 09/01/2026
LiveCodeBench v6Overall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner89.484 %
88.485 %
Vals AI
Source details
Data as of: 09/01/2026
MedCodeOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
48.135 %
Winner59.062 %
Vals AI
Source details
Data as of: 09/01/2026
MedScribeOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner84.496 %
76.114 %
Vals AI
Source details
Data as of: 09/01/2026
MMLU-ProOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
90.221 %
Winner90.987 %
Vals AI
Source details
Data as of: 09/01/2026
MMMU-ProOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner89.075 %
88.208 %
Vals AI
Source details
Data as of: 09/01/2026
MortgageTaxOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
65.342 %
Winner69.396 %
Vals AI
Source details
Data as of: 09/01/2026
ProgramBenchOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner1 %
0 %
Vals AI
Source details
Data as of: 09/01/2026
ProofBenchOverall
Test details
No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is better
Winner48 %
26 %
Vals AI
Source details
Data as of: 09/01/2026
Public Benefits Bench v1.1Overall
Test details
No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is better
Winner65.291 %
53.789 %
Vals AI
Source details
Data as of: 09/01/2026
SAGEOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
35.064 %
Winner48.677 %
Vals AI
Source details
Data as of: 09/01/2026
SWE-bench VerifiedOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner80 %
78.8 %
Vals AI
Source details
Data as of: 09/01/2026
TaxEval v2Overall
Test details
No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better
Winner74.448 %
72.882 %
Vals AI
Source details
Data as of: 09/01/2026
Terminal-Bench 2.1Overall
Test details
No documented difference in the test setupVersion: 2.1Metric: accuracyScoring: Higher is better
Winner81.273 %
70.787 %
Vals AI
Source details
Data as of: 09/01/2026
Vals IndexOverall
Test details
No documented difference in the test setupVersion: 2Metric: weighted index scoreScoring: Higher is better
Winner62.252 %
41.903 %
Vals AI
Source details
Data as of: 09/01/2026
Vibe Code Bench v1.1Overall
Test details
No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands
Winner78.651 %
32.034 %
Vals AI
Source details
Data as of: 09/01/2026

Key to the marks:better valuebetter, but not conclusivetie

How to read this comparison

Winning one benchmark is not an overall verdict

Your workload, budget, and required context length matter most. A coding benchmark says little about visual understanding or agent performance.

The standard price table uses direct developer rates. The provider comparison labels OpenRouter endpoints, regions, and special tariffs separately.

Every result links to its measurement source and retrieval date. Labels distinguish vendor reports, official benchmark leaderboards, and independent evaluations. Disputed or archived results are excluded.

More matchups

Related LLM comparisons

Compare Gemini 3.8 Flash and Gemini 3.1 Pro Preview with other leading models using the same data and benchmark logic.

View the complete LLM comparison