Claude Opus 5 vs Gemini 3.5 Flash: pricing and benchmarks
Gemini 3.5 Flash is 70% cheaper on input tokens ($1.50 vs $5.00 per 1M). Gemini 3.5 Flash is 64% cheaper on output tokens ($9.00 vs $25.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 3.5 Flash costs $870.00 a month versus $2,750 for Claude Opus 5, 68% less. Claude Opus 5 scores 162.3 on the Epoch Capabilities Index vs 154.7 for Gemini 3.5 Flash.
Prices verified September 14, 2026.
Which should you choose?
Claude Opus 5 scores 162.3 on the Epoch Capabilities Index vs 154.7 for Gemini 3.5 Flash.
Claude Opus 5 scores 73.6% on DeepSWE vs 37.4% for Gemini 3.5 Flash.
Claude Opus 5 scores 85.6% on FrontierMath (Tiers 1–3) vs 62.8% for Gemini 3.5 Flash.
Gemini 3.5 Flash costs $3.375 per 1M tokens (3:1 input-to-output mix) vs $10.00 for Claude Opus 5, 66% less.
A trade-off: Claude Opus 5 is 7.6 ECI points more capable but costs 3.0x as much as Gemini 3.5 Flash.
Pricing and specs
| Claude Opus 5 | Gemini 3.5 Flash | |
|---|---|---|
| Provider | Anthropic | |
| API model ID | claude-opus-5 | gemini-3.5-flash |
| Input / 1M tokens | $5.00 | $1.50 |
| Cached input / 1M tokens | $0.50 | $0.15 |
| Output / 1M tokens | $25.00 | $9.00 |
| Long-context rates | — | — |
| Context window | 1M tokens | 1.05M tokens |
| Max output | 128K tokens | 66K tokens |
| Batch discount | 50% off | 50% off |
Benchmarks
| Claude Opus 5 | Gemini 3.5 Flash | |
|---|---|---|
| Epoch Capabilities Index | 162.3 | 154.7 |
| GPQA Diamond· Science reasoning | 91.8% | 90.4% |
| FrontierMath (Tiers 1–3)· Advanced math | 85.6% | 62.8% |
| SimpleQA Verified· Factual accuracy | 59.9% | 66.2% |
| ARC-AGI-2· Abstract reasoning | 90.4% | 72.1% |
| DeepSWE· Coding | 73.6% | 37.4% |
| APEX-Agents· Agentic work | 43.5% | — |
Source: Epoch AI, best recorded result per model (CC BY 4.0). A dash means no published score. See all benchmarks
Monthly cost for real workloads
| Workload | Claude Opus 5 | Gemini 3.5 Flash | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $1,750 | $585.00 | Gemini 3.5 Flash 67% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $2,750 | $870.00 | Gemini 3.5 Flash 68% cheaper |
Coding agent 10,000 agent steps a month, ~40,000 input tokens each (70% read from the prompt cache) and ~2,000 output tokens. | $1,240 | $402.00 | Gemini 3.5 Flash 68% cheaper |
Estimates use standard list prices and ignore cache-write surcharges. Different tokenizers can count the same text differently, so test with your own prompts.
Claude Opus 5 vs Gemini 3.5 Flash cost calculator
- $870.00/mo$0.02 / request
- Claude Opus 5Anthropic$2,750/mo$0.06 / request
Standard-tier list prices. Long-context rates apply automatically where the provider publishes a threshold. Excludes cache-write surcharges, taxes, batch and volume discounts.
Claude Opus 5 pricing notes
Anthropic’s model for complex agentic coding and enterprise work.
- Cache writes cost $6.25 (5-minute cache) or $10 (1-hour cache) per 1M tokens.
- Uses Anthropic’s newer tokenizer, which produces roughly 30% more tokens for the same text.
- US-only inference (inference_geo: "us") costs 1.1x.
Gemini 3.5 Flash pricing notes
Google’s Gemini 3.5 Flash model, with thinking, tool use and a 1M-token context window.
- Output price includes thinking tokens.
- Context cache storage costs $1.00 per 1M tokens per hour.
- Priority inference costs 1.8x the standard rate.
Frequently asked questions
- Is Claude Opus 5 cheaper than Gemini 3.5 Flash?
- Gemini 3.5 Flash is 70% cheaper on input tokens ($1.50 vs $5.00 per 1M). Gemini 3.5 Flash is 64% cheaper on output tokens ($9.00 vs $25.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 3.5 Flash costs $870.00 a month versus $2,750 for Claude Opus 5, 68% less.
- Which is more capable, Claude Opus 5 or Gemini 3.5 Flash?
- Claude Opus 5 scores 162.3 on the Epoch Capabilities Index vs 154.7 for Gemini 3.5 Flash.
- How much does Claude Opus 5 cost per 1M tokens?
- Claude Opus 5 costs $5.00 per 1M input tokens and $25.00 per 1M output tokens, and $0.50 per 1M cached input tokens on Anthropic’s standard tier.
- How much does Gemini 3.5 Flash cost per 1M tokens?
- Gemini 3.5 Flash costs $1.50 per 1M input tokens and $9.00 per 1M output tokens, and $0.15 per 1M cached input tokens on Google’s standard tier.
- Which has the larger context window, Claude Opus 5 or Gemini 3.5 Flash?
- Gemini 3.5 Flash has the larger context window: 1.05M tokens versus 1M for Claude Opus 5.