Claude Sonnet 5 vs Gemini 3.5
Pricing, benchmarks, and use case comparison
Verdict
Two of the best price-performance frontier models of 2026: pick Claude Sonnet 5 for stronger agentic coding depth, pick Gemini 3.5 Flash for faster, cheaper output and stronger multimodal and tool-use benchmarks.
Specs comparison
| Claude Sonnet 5 | Gemini 3.5 | |
|---|---|---|
| Provider | Anthropic | Google DeepMind |
| Type | Closed source | Closed source |
| Context window | ✓1M | 1,048,576 tokens (Gemini 3.5 Flash; Pro variant not yet released) |
| Input / 1M tokens | $3.00 | ✓$1.50 |
| Output / 1M tokens | $15.00 | $9.00 |
| Release date | 2026-06 | 2026-05 |
Benchmarks
| Benchmark | Claude Sonnet 5 | Gemini 3.5 |
|---|---|---|
| SWE-bench Verified | ~85.2% | - |
| Terminal-Bench 2.1 | 80.4% | - |
| SWE-bench Pro | 63.2% | - |
| OSWorld-Verified | 81.2% | - |
| Terminal-Bench 2.1 (coding) | - | 76.2% |
| MCP Atlas (tool use) | - | 83.6% |
| CharXiv Reasoning (multimodal) | - | 84.2% |
Scores sourced from official provider release posts and independent benchmark aggregators.
Capability and benchmarks
These land very close. Claude Sonnet 5 posts 80.4% Terminal-Bench 2.1, ~85.2% SWE-bench Verified, and 81.2% OSWorld-Verified for computer use. Gemini 3.5 Flash posts 76.2% Terminal-Bench 2.1, 83.6% MCP Atlas tool use, and 84.2% CharXiv multimodal reasoning. Sonnet 5 has the edge on pure coding and terminal agent depth (coding 92 vs 90); Gemini leads on multimodal (90 vs 85) and function-calling reliability. They lack a fully shared public coding number, so treat this as a genuine trade rather than a clean win.
Price, speed, and context
Both carry a ~1M-token context. On price, Gemini 3.5 Flash is $1.50/$9 per 1M versus Sonnet 5's $3/$15 standard ($2/$10 introductory through Aug 31, 2026). Gemini is also the speed leader, generating output roughly 4x faster than prior Pro models (capability speed 90 vs 82). One caveat on Sonnet 5: its new tokenizer emits ~30% more tokens for the same text, so effective cost can rise even though per-token rates look mid-tier.
Which to pick
- Pick Sonnet 5 for agentic coding assistants, computer-use automation, and tasks where its self-checking and long-horizon completion matter.
- Pick Gemini 3.5 Flash for the cheapest, fastest option, heavy multimodal input (charts, documents, images), and agents that fire many tool calls.
Which should you choose?
Choose Claude Sonnet 5 if...
- →You want frontier-adjacent agentic coding but need better cost-efficiency than Opus
- →You are running high-volume agent loops and want strong reasoning per dollar
- →You are already on Sonnet 4.6 and want a same-price capability upgrade
- →You need a 1M context window with fast latency
Choose Gemini 3.5 if...
- →You need frontier agent/coding performance without frontier prices
- →Building autonomous agents that make many tool calls
- →High-throughput production workloads that were previously too costly on a Pro model
- →You want a strong default multimodal model with a 1M-token context window