Model comparison
Gemini 3.5 Flash-Lite vs GPT-5.6 Luna
Head-to-head evidence from 18 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Gemini 3.5 Flash-Lite unranked (Not scored); GPT-5.6 Luna #22 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Gemini 3.5 Flash-Lite and GPT-5.6 Luna share 18 comparable benchmark results. 2 of 8 categories are comparable. 3 results are unique to Gemini 3.5 Flash-Lite; 23 to GPT-5.6 Luna.
Updated July 21, 2026- Shared results
- 18
- Gemini 3.5 Flash-Lite only
- 3
- GPT-5.6 Luna only
- 23
- Comparable categories
- 2 / 8
Treat this as a split decision. Gemini 3.5 Flash-Lite makes more sense if you want the cheaper token bill; GPT-5.6 Luna is the better fit if agentic is the priority.
Confidence note. This is a partial-evidence comparison with 18 shared benchmark results across 5 evidence categories; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Gemini 3.5 Flash-Lite and GPT-5.6 Luna finish on the same BenchAlign overall score, so this is less about a single winner and more about where the edge shows up. The BenchAlign headline says tie; the benchmark table is where the real choice happens.
GPT-5.6 Luna is also the more expensive model on tokens at $1.00 input / $6.00 output per 1M tokens, versus $0.30 input / $2.50 output per 1M tokens for Gemini 3.5 Flash-Lite. That is roughly 2.4x on output cost alone.
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 | Gemini 3.5 Flash-Lite | Δ | GPT-5.6 Luna |
|---|---|---|---|
| Agentic | Gemini 3.5 Flash-Lite63.4 | Margin→ 20.7 | GPT-5.6 Luna84.1 |
| Coding | Gemini 3.5 Flash-Lite54.2 | Margin→ 8.5 | GPT-5.6 Luna62.7 |
| Reasoning | Gemini 3.5 Flash-Lite72.2 | MarginNo overlap | GPT-5.6 LunaNot measured |
| Knowledge | Gemini 3.5 Flash-LiteNot measured | MarginNo overlap | GPT-5.6 Luna92.3 |
| Math | Gemini 3.5 Flash-LiteNot measured | MarginNo overlap | GPT-5.6 Luna73.6 |
| Multimodal | Gemini 3.5 Flash-LiteNot measured | MarginNo overlap | GPT-5.6 Luna78.4 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
Terminal-Bench 2.0
AgenticA 54%B 84.7%Winner: GPT-5.6 LunaΔ 30.7Terminal-Bench 2.0: Gemini 3.5 Flash-Lite scored 54%; GPT-5.6 Luna scored 84.7%. GPT-5.6 Luna wins this benchmark. - Source ↗
SWE-bench Pro
CodingA 54.2%B 62.7%Winner: GPT-5.6 LunaΔ 8.5SWE-bench Pro: Gemini 3.5 Flash-Lite scored 54.2%; GPT-5.6 Luna scored 62.7%. GPT-5.6 Luna wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Gemini 3.5 Flash-Lite | GPT-5.6 Luna | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Gemini 3.5 Flash-Lite$0.3 input / $2.5 output | GPT-5.6 Luna$1 input / $6 output | Gemini 3.5 Flash-Lite has the lower combined listed price. |
| Generation speedtokens per second | Gemini 3.5 Flash-LiteNot available | GPT-5.6 LunaNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Gemini 3.5 Flash-LiteNot available | GPT-5.6 LunaNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Gemini 3.5 Flash-Lite1M | GPT-5.6 Luna1M | Listed context windows are equal. |
Benchmark Deep Dive
AgenticGPT-5.6 Luna wins17 benchmarks
| Benchmark | Gemini 3.5 Flash-Lite | GPT-5.6 Luna | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 54% | 84.7% | GPT-5.6 Luna leads |
| OSWorld-VerifiedSource | 74% | — | Not comparable |
| GDPval-AASource | 1140 | 1584 | GPT-5.6 Luna leads |
| AA Agentic IndexSource | 26.8% | 45.6% | GPT-5.6 Luna leads |
| GDPval-AASource | 32.0% | 54.2% | GPT-5.6 Luna leads |
| AA BriefcaseSource | 634 | — | Not comparable |
| AA Tau3 BankingSource | 16.5% | 27.2% | GPT-5.6 Luna leads |
| BrowseCompSource | — | 83.3% | Not comparable |
| OSWorld 2.0Source | — | 45.6% | Not comparable |
| CyberGymSource | — | 77.9% | Not comparable |
| ExploitGymSource | — | 12.4% | Not comparable |
| ToolathlonSource | — | 53.4% | Not comparable |
| AA Harvey LABSource | — | 87.9% | Not comparable |
| AA ITBenchSource | — | 40.3% | Not comparable |
| AA AutomationBenchSource | — | 42.2% | Not comparable |
| aaTerminalBench21Source | — | 80.9% | Not comparable |
| APEX-Agents-AASource | — | 35.8% | Not comparable |
CodingGPT-5.6 Luna wins7 benchmarks
| Benchmark | Gemini 3.5 Flash-Lite | GPT-5.6 Luna | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 54.0% | 84.7% | GPT-5.6 Luna leads |
| SWE-bench ProSource | 54.2% | 62.7% | GPT-5.6 Luna leads |
| AA Coding IndexSource | 49.3% | 71.5% | GPT-5.6 Luna leads |
| AA-SciCodeSource | 40.9% | 52.5% | GPT-5.6 Luna leads |
| deepSweSource | — | 67.2% | Not comparable |
| FrontierCode 1.1 ExtendedSource | — | 55.1% | Not comparable |
| cursorBench32Source | — | 61.1% | Not comparable |
Reasoning4 benchmarks
Knowledge10 benchmarks
| Benchmark | Gemini 3.5 Flash-Lite | GPT-5.6 Luna | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 36.5% | 51.2% | GPT-5.6 Luna leads |
| AA-GPQA DiamondSource | 83.8% | 91.1% | GPT-5.6 Luna leads |
| AA-HLESource | 17.5% | 37.2% | GPT-5.6 Luna leads |
| AA-Omniscience IndexSource | 6.9% | -11.2% | Gemini 3.5 Flash-Lite leads |
| AA-Omniscience AccuracySource | 30.3% | 41.5% | GPT-5.6 Luna leads |
| AA-Omniscience Hallucination RateSource | 33.5% | 90.1% | Gemini 3.5 Flash-Lite leads |
| GPQASource | — | 92.3% | Not comparable |
| GPQA-DSource | — | 92.3% | Not comparable |
| HealthBench ProfessionalSource | — | 55.7% | Not comparable |
| HealthBench HardSource | — | 32.0% | Not comparable |
Math3 benchmarks
Frequently Asked Questions (3)
Which is better, Gemini 3.5 Flash-Lite or GPT-5.6 Luna?
Gemini 3.5 Flash-Lite and GPT-5.6 Luna are tied on the BenchAlign overall score, so the right pick depends on which category matters most for your use case.
Which is better for coding, Gemini 3.5 Flash-Lite or GPT-5.6 Luna?
GPT-5.6 Luna has the edge for coding in this comparison, averaging 62.7 versus 54.2. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Which is better for agentic tasks, Gemini 3.5 Flash-Lite or GPT-5.6 Luna?
GPT-5.6 Luna has the edge for agentic tasks in this comparison, averaging 84.1 versus 63.4. Inside this category, GDPval-AA is the benchmark that creates the most daylight between them.
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