Skip to main content
BenchLM
Advertise

Model comparison

Gemini 3 Flash vs GPT-5.3 Codex

Data verified

Head-to-head evidence from 16 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

60.49/100
Margin
6.2pts
winning →
66.69/100
0 category wins0 category wins

Public leaderboard positions: Gemini 3 Flash #49 (Supported); GPT-5.3 Codex #26 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Gemini 3 Flash and GPT-5.3 Codex share 16 comparable benchmark results. 0 of 8 categories are comparable. 3 results are unique to Gemini 3 Flash; 5 to GPT-5.3 Codex.

Updated July 20, 2026
Shared results
16
Gemini 3 Flash only
3
GPT-5.3 Codex only
5
Comparable categories
0 / 8

Benchmark data for Gemini 3 Flash and GPT-5.3 Codex is coming soon on BenchLM.

Confidence note. This is a partial-evidence comparison with 16 shared benchmark results across 6 evidence categories; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

BenchLM has partial data for these models, but not enough overlapping benchmark coverage to produce a fair score-level comparison yet.

GPT-5.3 Codex is priced at $1.75 input / $14.00 output per 1M tokens, versus $0.50 input / $3.00 output per 1M tokens for Gemini 3 Flash. Gemini 3 Flash has the larger context window at 1M, compared with 400K for GPT-5.3 Codex.

Category breakdown

Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.

Category scores and score margins for Gemini 3 Flash and GPT-5.3 Codex
CategoryGemini 3 FlashΔGPT-5.3 Codex
AgenticGemini 3 FlashNot measuredMarginNo overlapGPT-5.3 Codex71.4
CodingGemini 3 FlashNot measuredMarginNo overlapGPT-5.3 Codex67.2
MathGemini 3 Flash27.8MarginNo overlapGPT-5.3 CodexNot measured

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

MetricGemini 3 FlashGPT-5.3 CodexComparison
Input / output priceUSD per 1M tokensGemini 3 Flash$0.5 input / $3 outputGPT-5.3 Codex$1.75 input / $14 outputGemini 3 Flash has the lower combined listed price.
Generation speedtokens per secondGemini 3 Flash159 tok/sGPT-5.3 Codex79 tok/sGemini 3 Flash has the higher measured throughput.
First-answer latencyseconds to first tokenGemini 3 Flash1.19 sGPT-5.3 Codex88.26 sGemini 3 Flash reaches the first token sooner.
Context windowmaximum listed tokensGemini 3 Flash1MGPT-5.3 Codex400KGemini 3 Flash lists the larger context window.

Benchmark Deep Dive

Agentic
BenchmarkGemini 3 FlashGPT-5.3 CodexResult
Claw-EvalSource 49.2%—Not comparable
τ²-bench resultsSource 43.3%86%GPT-5.3 Codex leads
Gert LabsSource 56.63%57.47%GPT-5.3 Codex leads
JobBenchSource 11.4%33.7%GPT-5.3 Codex leads
Terminal-Bench 2.0Source —77.3%Not comparable
OSWorld-VerifiedSource —64.7%Not comparable
Coding
BenchmarkGemini 3 FlashGPT-5.3 CodexResult
Vibe Code BenchSource 20.20%61.77%GPT-5.3 Codex leads
AA-SciCodeSource 49.9%53.2%GPT-5.3 Codex leads
SWE-bench VerifiedSource —85%Not comparable
SWE-bench ProSource —56.8%Not comparable
SWE-RebenchSource —58.2%Not comparable
Reasoning
BenchmarkGemini 3 FlashGPT-5.3 CodexResult
AA-LCRSource 48.0%74.0%GPT-5.3 Codex leads
CritPtSource 1.4%16.9%GPT-5.3 Codex leads
Knowledge
BenchmarkGemini 3 FlashGPT-5.3 CodexResult
Artificial Analysis Intelligence IndexSource 27.4%44.3%GPT-5.3 Codex leads
AA-GPQA DiamondSource 81.2%91.5%GPT-5.3 Codex leads
AA-HLESource 14.1%39.9%GPT-5.3 Codex leads
AA-Omniscience IndexSource -3.6%9.9%GPT-5.3 Codex leads
AA-Omniscience AccuracySource 45.5%51.8%GPT-5.3 Codex leads
AA-Omniscience Hallucination RateSource 90.2%86.9%GPT-5.3 Codex leads
Math
BenchmarkGemini 3 FlashGPT-5.3 CodexResult
FrontierMath v2 (Tiers 1-3)Source 35.640%—Not comparable
FrontierMath v2 (Tier 4)Source 4.167%—Not comparable
Multimodal
BenchmarkGemini 3 FlashGPT-5.3 CodexResult
AA-MMMU-ProSource 78.6%78.5%Gemini 3 Flash leads
Design Arena WebsiteSource 12281195Gemini 3 Flash leads
Inst. Following
BenchmarkGemini 3 FlashGPT-5.3 CodexResult
AA-IFBenchSource 55.1%75.4%GPT-5.3 Codex leads
Frequently Asked Questions (3)

Can I compare Gemini 3 Flash and GPT-5.3 Codex on BenchLM yet?

Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.

Why does this comparison show “coming soon”?

BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.

What data is available for Gemini 3 Flash and GPT-5.3 Codex today?

Gemini 3 Flash: $0.50 input / $3.00 output per 1M tokens GPT-5.3 Codex: $1.75 input / $14.00 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.

Related Comparisons

Explore More

Google Compare Pricing Methodology Find Your Best LLM Overall Rankings
Last updated: July 20, 2026

Choose a model with this week’s evidence

Join 2,000+ readers for ranking moves, pricing changes, and the claims that still need proof.

One email each week. Unsubscribe anytime.