Claude Sonnet 5.5 vs Gemini 2.5 Pro: pricing and benchmarks
Gemini 2.5 Pro is 38% cheaper on input tokens ($1.25 vs $2.00 per 1M). Both charge $10.00 per 1M output tokens. On our document Q&A workload (50,000 questions a month), Gemini 2.5 Pro costs $800.00 a month versus $1,100 for Claude Sonnet 5.5, 27% less. Epoch AI has not published a capability index score for Claude Sonnet 5.5 yet.
Prices verified September 28, 2026.
Which should you choose?
Epoch AI has not published a capability index score for Claude Sonnet 5.5 yet.
Gemini 2.5 Pro costs $3.438 per 1M tokens (3:1 input-to-output mix) vs $4.00 for Claude Sonnet 5.5, 14% less.
Pricing and specs
| Claude Sonnet 5.5 | Gemini 2.5 Pro | |
|---|---|---|
| Provider | Anthropic | |
| API model ID | claude-sonnet-5-5 | gemini-2.5-pro |
| Input / 1M tokens | $2.00 | $1.25 |
| Cached input / 1M tokens | $0.20 | $0.125 |
| Output / 1M tokens | $10.00 | $10.00 |
| Long-context rates | — | $2.50 in / $15.00 out above 200K prompt tokens |
| Context window | 1M tokens | 1.05M tokens |
| Max output | 128K tokens | 66K tokens |
| Batch discount | 50% off | — |
Benchmarks
| Claude Sonnet 5.5 | Gemini 2.5 Pro | |
|---|---|---|
| Epoch Capabilities Index | — | 145.3 |
| GPQA Diamond· Science reasoning | — | 80.4% |
| FrontierMath (Tiers 1–3)· Advanced math | — | 24.6% |
| SimpleQA Verified· Factual accuracy | — | — |
| ARC-AGI-2· Abstract reasoning | — | 4.9% |
| DeepSWE· Coding | — | — |
| APEX-Agents· Agentic work | — | 6.6% |
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 Sonnet 5.5 | Gemini 2.5 Pro | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $700.00 | $587.50 | Gemini 2.5 Pro 16% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $1,100 | $800.00 | Gemini 2.5 Pro 27% 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. | $496.00 | $385.00 | Gemini 2.5 Pro 22% 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 Sonnet 5.5 vs Gemini 2.5 Pro cost calculator
- $800.00/mo$0.02 / request
- Claude Sonnet 5.5Anthropic$1,100/mo$0.02 / 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 Sonnet 5.5 pricing notes
Anthropic’s fast mid-tier model, successor to Claude Sonnet 5 at the same price.
- Cache writes cost $2.50 (5-minute cache) or $4 (1-hour cache) per 1M tokens.
- US-only inference (inference_geo: "us") costs 1.1x.
Gemini 2.5 Pro pricing notes
Google’s previous-generation Pro model.
- Prompts over 200K tokens are billed at $2.50 input / $15 output per 1M tokens.
- Output price includes thinking tokens.
Frequently asked questions
- Is Claude Sonnet 5.5 cheaper than Gemini 2.5 Pro?
- Gemini 2.5 Pro is 38% cheaper on input tokens ($1.25 vs $2.00 per 1M). Both charge $10.00 per 1M output tokens. On our document Q&A workload (50,000 questions a month), Gemini 2.5 Pro costs $800.00 a month versus $1,100 for Claude Sonnet 5.5, 27% less.
- Which is more capable, Claude Sonnet 5.5 or Gemini 2.5 Pro?
- Epoch AI has not published a capability index score for Claude Sonnet 5.5 yet.
- How much does Claude Sonnet 5.5 cost per 1M tokens?
- Claude Sonnet 5.5 costs $2.00 per 1M input tokens and $10.00 per 1M output tokens, and $0.20 per 1M cached input tokens on Anthropic’s standard tier.
- How much does Gemini 2.5 Pro cost per 1M tokens?
- Gemini 2.5 Pro costs $1.25 per 1M input tokens and $10.00 per 1M output tokens, and $0.125 per 1M cached input tokens on Google’s standard tier.
- Which has the larger context window, Claude Sonnet 5.5 or Gemini 2.5 Pro?
- Gemini 2.5 Pro has the larger context window: 1.05M tokens versus 1M for Claude Sonnet 5.5.