GoogleGemini 3 FlashVSGoogleGemini 3.5 Flash

Analysis by:the whichllmmodel Editorial Team|Updated: June 2026

Our Take

We recommend Gemini 3.5 Flash for complex complex codebases, multi-file repositories, and architectural planning, or the 3.0x cheaper Gemini 3 Flash if your workflow is limited to multi-file code and clearly defined tasks. While they share very similar reasoning capabilities, Gemini 3.5 Flash handles repository-scale projects whereas Gemini 3 Flash excels at basic functions and scripts. Choose Gemini 3.5 Flash for architectural codebase planning, or Gemini 3 Flash to save on API costs for simple scripts.

▶WHY?

Benchmark Calculations & Evidence:

Coding Evaluation: Gemini 3 Flash was evaluated on SWE-bench Verified (scoring 78%), while Gemini 3.5 Flash was evaluated on SWE-bench Pro (scoring 55.1%).

Reasoning Accuracy: Both models were evaluated on the GPQA Diamond benchmark. Gemini 3 Flash scored 90.4%, while Gemini 3.5 Flash scored 92.2%.

Cost Efficiency: Gemini 3 Flash pricing ($0.5/M input, $3/M output) is 3.0x cheaper than Gemini 3.5 Flash ($1.5/M input, $9/M output).

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Model Specs

Gemini 3 Flash

Website

Benchmarks & Scores

Coding (swe-bench-verified)

78%

multi-file code and clearly defined tasks

Reasoning (gpqa-diamond)

90.4%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)3.0x cheaper

$1.13Input: $0.50 | Output: $3.00

Context Window

1.05M tokens

Model Specs

Gemini 3.5 Flash

Website

Benchmarks & Scores

Coding (swe-bench-pro)

55.1%

complex codebases, multi-file repositories, and architectural planning

Reasoning (gpqa-diamond)Winner (+1.8%)

92.2%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)

$3.38Input: $1.50 | Output: $9.00

Context Window

1.05M tokens

Read our data collection methodology

Frequently Asked Questions about Gemini 3 Flash vs Gemini 3.5 Flash

Gemini 3 Flash is cheaper than Gemini 3.5 Flash. Gemini 3 Flash has a blended cost of $1.13/1M tokens, which is about 3.0x cheaper than Gemini 3.5 Flash at $3.38/1M tokens.

For coding tasks, Gemini 3 Flash scores 78% on swe-bench-verified (multi-file code and clearly defined tasks), while Gemini 3.5 Flash scores 55.1% on swe-bench-pro (complex codebases, multi-file repositories, and architectural planning).

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