Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | GPT-5 (medium) | Gemini 2.5 Pro |
|---|---|---|
| Input ($/M tokens) | $1.25 | $1.25 |
| Output ($/M tokens) | $10 | $10 |
Verdict. GPT-5 (medium) and Gemini 2.5 Pro split the benchmark comparison evenly at 1–1. The tiebreaker here is price, speed, and what you actually run them on.
Pricing. Both models sit in the mid-tier bracket for output-token pricing. At 1.0× the per-million-token cost, Gemini 2.5 Pro is meaningfully cheaper if your traffic is output-heavy (long completions, document generation, agent loops). Gemini 2.5 Pro makes more sense when output volume is low and absolute reasoning quality justifies the premium.
Strengths. GPT-5 (medium) is strongest on Intelligence Index (34.6). Gemini 2.5 Pro leads on Coding Index (33.3), Intelligence Index (25.9).
Speed. On throughput, Gemini 2.5 Pro generates tokens at 133 tok/s versus 99 tok/s — about 26% faster. On time-to-first-token, Gemini 2.5 Pro responds in 20460ms vs 26680ms, which matters most for chat-style UIs.
Provider. OpenAI and Google sell to overlapping but distinct developer audiences: OpenAI tends to ship frontier reasoning models with premium positioning, while Google 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): GPT-5 (medium) costs $187.50 ($2250/year); Gemini 2.5 Pro costs $187.50 ($2250/year). At a smaller 5M-input/2M-output scale (single-developer tool or prototype): GPT-5 (medium) ≈ $26.25/run, Gemini 2.5 Pro ≈ $26.25/run. At agent/realtime scale (200M input / 100M output per million requests): GPT-5 (medium) ≈ $1250/run, Gemini 2.5 Pro ≈ $1250/run.
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.
Head-to-head deltas
Data from Artificial Analysis API — 12 benchmarks
Both models have similar pricing. Check the detailed breakdown above for input vs output token costs.
It's a tie — both models win 1 benchmarks each across 12 evaluated categories. See the detailed benchmark chart above for per-category results.
Gemini 2.5 Pro generates tokens faster at 133 tok/s vs 99 tok/s. However, Gemini 2.5 Pro has lower time-to-first-token (20.46s vs 26.68s).
Choose based on your priorities: both are similarly priced, both perform similarly on benchmarks, and Gemini 2.5 Pro for faster generation. For latency-sensitive apps, check the TTFT comparison above.