Claude Sonnet 5 vs GPT-5.5: Which Is Better for Coding? (2026)

head-to-head

Metric	Claude Sonnet 5	GPT-5.5
SWE-bench Verified	85.2%	82.6%
SWE-bench Pro	63.2%	58.6%
Terminal-Bench	80.4% (TB2.1)	82.7% (TB2.0)
Input $ / 1M	$2	—
Context	1M	—
Open weights	No	No
Maker	Anthropic	OpenAI

when to pick each

Pick Claude Sonnet 5 if

The best closed-model value — near-Opus scores at ~2.5× less, and the default daily driver for most developers.

Pick GPT-5.5 if

OpenAI's strongest agentic coder, with the deepest tooling and ecosystem breadth of the closed labs.

Full reviewsClaude Sonnet 5, decoded

Ranked on our AI Coding Leaderboard, updated 2026-07-02. Scores are confirmed against primary sources; prices are per 1M input tokens and can change.

Primary sources

AnthropicGENZ TECH — Claude Sonnet 5, decoded — Anthropic-reported. Intro pricing $2/$10 per 1M through Aug 31, 2026, then $3/$15.
OpenAIvals.ai — SWE-bench Verified (independent) — Verified score from vals.ai independent eval; Pro is OpenAI-reported (rivals flag possible memorization on Pro).
BenchmarkSWE-bench — the real-GitHub-issue benchmark

$ quick-answers

Is Claude Sonnet 5 better than GPT-5.5 for coding?

Claude Sonnet 5 scores higher on SWE-bench Verified (85.2% vs 82.6%) and SWE-bench Pro, so it is the stronger coder on current benchmarks.

Which is cheaper, Claude Sonnet 5 or GPT-5.5?

Public per-token pricing isn't confirmed for both, so we don't print a price comparison yet.

Should I use Claude Sonnet 5 or GPT-5.5?

Claude Sonnet 5 for the hardest, highest-stakes coding; GPT-5.5 when you want the best value or are running high volume. Both are frontier-class in 2026.