Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | Gemini 3.1 Flash-Lite | GPT-3.5 Turbo |
|---|---|---|
| Input ($/M tokens) | $0.25 | $0.5 |
| Output ($/M tokens) | $1.5 | $1.5 |
Verdict. Gemini 3.1 Flash-Lite wins the overall benchmark matchup 2–0 across 2 overlapping categories, but raw benchmark score is only one input to the decision.
Pricing. Both models sit in the budget bracket for output-token pricing. At 1.0× the per-million-token cost, GPT-3.5 Turbo is meaningfully cheaper if your traffic is output-heavy (long completions, document generation, agent loops). GPT-3.5 Turbo makes more sense when output volume is low and absolute reasoning quality justifies the premium.
Strengths. Gemini 3.1 Flash-Lite is strongest on Coding Index (34.7), Intelligence Index (25.6). GPT-3.5 Turbo leads on Coding Index (10.7), Intelligence Index (3.2).
Speed. Speed data is incomplete for this pair; benchmark and price should decide.
Provider. Google and OpenAI sell to overlapping but distinct developer audiences: Google tends to ship frontier reasoning models with premium positioning, while OpenAI often prices more aggressively. Your existing vendor relationships, billing, and SLA preferences may matter as much as the raw numbers above.
Workload cost. Workload scenarios (per million requests at 30M input + 15M output tokens): Gemini 3.1 Flash-Lite costs $30.00 ($360/year); GPT-3.5 Turbo costs $37.50 ($450/year). At a smaller 5M-input/2M-output scale (single-developer tool or prototype): Gemini 3.1 Flash-Lite ≈ $4.25/run, GPT-3.5 Turbo ≈ $5.50/run. At agent/realtime scale (200M input / 100M output per million requests): Gemini 3.1 Flash-Lite ≈ $200/run, GPT-3.5 Turbo ≈ $250/run. Gemini 3.1 Flash-Lite becomes more attractive at higher volume — the absolute per-token pricing difference compounds when you ship at scale.
Recommendation. Both models have legitimate use cases — the right answer depends on whether you are optimizing for benchmark ceiling, latency, or unit cost. Start with the cheaper / faster model, evaluate against your specific task, and only switch if the upgrade shows a meaningful lift.
Data from Artificial Analysis API — 12 benchmarks
Gemini 3.1 Flash-Lite is cheaper overall. Its blended price (3:1 input/output ratio) is $0.56/M tokens vs $0.75/M for GPT-3.5 Turbo.
Gemini 3.1 Flash-Lite wins 2 out of 12 benchmarks compared to 0 for GPT-3.5 Turbo. See the detailed benchmark chart above for per-category results.
Gemini 3.1 Flash-Lite generates tokens faster at 346 tok/s vs — tok/s. Gemini 3.1 Flash-Lite also has lower time-to-first-token (5.64s vs —s).
Choose based on your priorities: Gemini 3.1 Flash-Lite for lower cost, Gemini 3.1 Flash-Lite for stronger benchmark performance, and Gemini 3.1 Flash-Lite for faster generation. For latency-sensitive apps, check the TTFT comparison above.