Anthropic releases Claude Sonnet 5.5, 30% faster and 30% cheaper
What happened
On September 28, 2026, Anthropic released Claude Sonnet 5.5, the second model in its Claude 5.5 series. It targets well-bounded work: everyday coding, bug fixes, documentation and slide decks. Anthropic says it runs more than 30% faster than the previous Sonnet 5 and cuts cost per task by up to 30%, because it uses fewer tokens for the same job rather than a lower unit price. Input and output pricing stays at $2 and $10 per million tokens. Coding gains are large: Terminal-Bench 4.0 rose from 10.3% to 70.6%. It scores 56 on the Artificial Analysis Intelligence Index, 2 points below Opus 5.5 and 18 points above Sonnet 5 at the same tier. Earlier reporting said a Sonnet 5.5 run cost about $7.60, 50% more than Sonnet 5, which conflicts with the later claim of up to 30% lower cost per task. The model is now the default on claude.ai's free tier and has entered voting on Arena's Agent leaderboard; on September 30 Arena reported it ranked 4th in Code Arena: WebDev with 1699 points. Haiku 5.5 is said to be a few weeks away.
Written by AI from the coverage · updated 4 hours ago
Developments
- Sep 30 02:15 · 1 reportClaude Sonnet 5.5 (High) 以 1699 分登 Code Arena: WebDev 第 4 名AI HOT · Models
- Sep 29 02:30 · 1 reportClaude Sonnet 5.5 enters Arena's Agent Arena and Battle ModeAI HOT (Curated Pool)
- Sep 29 02:02 · 3 reportsAnthropic's Claude Sonnet 5.5 nearly matches Opus 5.5 on benchmarks while costing up to 30% less per taskAI HOT (Curated Pool)
- Sep 29 01:58 · 5 reportsAnthropic launches Claude Sonnet 5.5: 30%+ faster, up to 30% cheaper than Sonnet 5Hacker News front page
- Sep 28 00:00 · 8 reportsClaude Sonnet 5.5 hits #2 on AA Intelligence Index, matching Opus 5.5 by spending ~193k output tokens per taskAI HOT (Curated Pool)
Coverage
Follow the reports to see the story from different sides.
- AI HOT · ModelsClaude Sonnet 5.5 (High) 以 1699 分登 Code Arena: WebDev 第 4 名
Arena 公布 Claude Sonnet 5.5 (High) 在 Code Arena: WebDev 以 1699 分排第 4，混合价格约 $8 per Mtoken，比第 2、3 名便宜 80%。相较 Sonnet 5 (High) 的 1540 分提升 159 分，Reference-Based Design、Simulations、Gaming 均从第 30 多名升至第 4。
- AI HOT (Curated Pool)PickAnthropic launches Claude Sonnet 5.5, now the free-tier default on claude.ai
Claude Sonnet 5.5 beats Sonnet 5 on every benchmark, runs 30%+ faster, and costs up to 30% less for most work. The big move: it's now the free-tier default on claude.ai, which Simon Willison tested and got a solid WebGL 3D pelican on a bicycle. The 'max' thinking effort still hits the same bug as Opus 5.5—128K tokens of thought with no output, costing $1.28. 'xhigh' delivered a decent SVG in 41 seconds for 5.74 cents. Anthropic says Haiku 5.5 is coming in weeks; Simon hopes it's price-competitive with GPT-6 Luna.
- AI HOT (Curated Pool)PickClaude Sonnet 5.5 Released with Official Build Guide
Anthropic released Claude Sonnet 5.5 alongside a build guide. The guide covers choosing between Sonnet 5.5 and Opus 5.5, migrating from Sonnet 5 and adjusting the effort parameter, and using it in Claude Code. The post body is just a title and link—no performance numbers or timeline details are disclosed.
- AI HOT (Curated Pool)PickAnthropic launches Claude Sonnet 5.5: 30%+ faster than Sonnet 5, up to 30% cheaper for most tasks
Anthropic released Claude Sonnet 5.5, the second model in the Claude 5.5 family. It runs 30%+ faster than Sonnet 5 and cuts costs by up to 30% for most workloads. Claude Code dev Thariq noted that Sonnet and Opus 5.5 make higher-level abstractions like projects, claude tag, and dynamic workflows more viable on token cost, and recommends trying Sonnet 5.5 first when building workflows. The post doesn't disclose specific benchmark scores or pricing figures.
- AI HOT (Curated Pool)PickAnthropic releases Claude Sonnet 5.5, scores 70.6% on Terminal-Bench 4.0 at unchanged pricing
Anthropic dropped Claude Sonnet 5.5 with a 70.6% score on Terminal-Bench 4.0, a huge jump from Sonnet 5's 10.3%. Pricing stays at $2/$10 per million input/output tokens. The post doesn't disclose architecture, training details, or exact availability, so I'd wait for third-party benchmarks before getting too excited.
- AI HOT (Curated Pool)PickAnthropic releases Claude Sonnet 5.5, over 30% faster than Sonnet 5 and up to 30% cheaper for most tasks
Anthropic launched Claude Sonnet 5.5, the second model in the 5.5 family. It's over 30% faster than Sonnet 5 and up to 30% cheaper for most tasks. Positioned for well-scoped daily work like bug fixes and fast feature iteration; Claude Code usage will also last longer. The post doesn't disclose benchmark scores or availability regions.
- AI HOT (Curated Pool)PickAnthropic launches Claude Sonnet 5.5, scoring 56 on the Artificial Analysis Intelligence Index, just 2 points below Opus 5.5
Claude Sonnet 5.5 scored 56 on the Artificial Analysis Intelligence Index, only 2 points behind Opus 5.5 at max effort. It beats Sonnet 5 by 18 points under max effort. The post doesn't disclose release date, pricing, or API details.
- AI HOT (Curated Pool)PickClaude Sonnet 5.5 enters Arena's Agent Arena and Battle Mode
Anthropic's Claude Sonnet 5.5 is now available for voting in Arena's Agent Arena. The leaderboard evaluates models on millions of real-world long-horizon agent tasks where models can use web search, filesystem, and terminal tools. Rankings use a causal tracking method to measure how much a model outperforms the average.
- AI HOT (Curated Pool)PickAnthropic launches Claude Sonnet 5.5: 30% faster, 30% cheaper, demoed fixing a Claude Code bug
Anthropic released Claude Sonnet 5.5, the second model in the Claude 5.5 family. It's over 30% faster than Sonnet 5 and up to 30% cheaper on most tasks. Boris Cherny posted a video showing Sonnet 5.5 fixing a bug inside Claude Code. The post doesn't disclose benchmark scores or exact pricing.
- AI HOT (Curated Pool)PickAnthropic launches Claude Sonnet 5.5: over 30% faster and up to 30% cheaper than Sonnet 5
Anthropic released Claude Sonnet 5.5, the second model in the Claude 5.5 family. It runs over 30% faster than Sonnet 5 and cuts costs by up to 30% on most workloads. The post does not disclose benchmarks, pricing details, or availability dates.
- AI HOT (Curated Pool)PickAnthropic releases Claude Sonnet 5.5, over 30% faster than Sonnet 5
Anthropic launched Claude Sonnet 5.5, claiming over 30% speed gains and clearer writing for fast-turnaround tasks like bug fixes, docs, and slide decks. Opus 5.5 targets complex judgment work, and Haiku 5.5 is coming in a few weeks. The post doesn't disclose pricing or latency numbers.
- AI HOT (Curated Pool)PickAnthropic launches Claude Sonnet 5.5, over 30% faster than Sonnet 5
Anthropic released Claude Sonnet 5.5, running over 30% faster than Sonnet 5 with clearer writing, built for fast back-and-forth interactions. It's positioned apart from Opus 5.5, which handles complex judgment work—Sonnet 5.5 targets well-scoped daily tasks, bug fixes, and producing docs, slides, and sheets. The model is fully available now; Haiku 5.5 will join the lineup in a few weeks. The post doesn't disclose pricing or benchmark scores.
- AI HOT (Curated Pool)PickAnthropic launches Claude Sonnet 5.5, over 30% faster and up to 30% cheaper on most tasks
Anthropic announced Claude Sonnet 5.5, the second model in the 5.5 family. It's over 30% faster than Sonnet 5 and up to 30% cheaper on most tasks. The post doesn't disclose benchmark scores, pricing details, or regional availability—hold for third-party benchmarks.
- AI HOT (Curated Pool)PickAnthropic launches Claude Sonnet 5.5, 30% faster and 30% cheaper
Anthropic released Claude Sonnet 5.5, the second model in the Claude 5.5 family. The company calls it a clear upgrade over Sonnet 5, running over 30% faster and cutting costs by up to 30% on most tasks. The post doesn't disclose benchmarks, pricing, or availability dates.
- AI HOT (Curated Pool)PickAnthropic's Claude Sonnet 5.5 nearly matches Opus 5.5 on benchmarks while costing up to 30% less per task
Anthropic released Claude Sonnet 5.5, aimed at everyday tasks like bug fixes and doc writing. It generates output over 30% faster and costs up to 30% less per task—not by lowering token price, but by using fewer tokens per task. Coding gains are the headline: Terminal-Bench 4.0 jumps from 10.3% (Sonnet 5) to 70.6%, and CursorBench 4.0 hits 55.5%, just 2.3 points below Opus 5.5. On the knowledge-work benchmark GDPval-AA, it scores 1,844 vs. Opus 5.5's 1,846. One oddity: max reasoning effort on FrontierCode scores worse than the second-highest setting; Anthropic says a code-review function caused timeouts or scope drift. The model is live on AWS, Google Cloud, and Azure, with new safeguards against cybersecurity risks and distillation attacks. The post does not disclose Haiku 5.5 specs or a firm launch date, only 'in the coming weeks.'
- TechCrunch · AIPickAnthropic releases Sonnet 5.5, calling it a significantly cheaper, faster work partner
Anthropic launched Claude Sonnet 5.5, its mid-tier model, pitched as a faster, cheaper assistant for coding and office docs. The post says it improves on Sonnet 5 in response time and token burn, but doesn't disclose exact pricing, speed multiples, or benchmark scores. I'd wait for third-party benchmarks before buying the 'significantly cheaper' claim.
- Hacker News front pagePickAnthropic launches Claude Sonnet 5.5: 30%+ faster, up to 30% cheaper than Sonnet 5
Claude Sonnet 5.5 is the second model in the 5.5 family, aimed at everyday coding, bug fixes, and polished docs. It scores 70.6% on Terminal-Bench 4.0 vs. Sonnet 5's 10.3%. Pricing stays at $2/$10 per million input/output tokens, but it uses fewer tokens per task, cutting per-task cost by up to 30%. Speed is up 30%+. For the first time, a Sonnet model ships with cyber safeguards because its cybersecurity capabilities now match Opus 5. Haiku 5.5 is coming in a few weeks.
- AI HOT (Curated Pool)PickClaude Sonnet 5.5 hits #2 on AA Intelligence Index, matching Opus 5.5 by spending ~193k output tokens per task
Anthropic released Claude Sonnet 5.5, scoring 56 on the AA Intelligence Index—2 points behind Opus 5.5. Pricing stays at $2/$10 per million input/output tokens, but cost per task hits ~$7.60, about 50% more than Sonnet 5, because it uses ~193k output tokens per task at max effort. That's 60% more than Opus 5.5 and 7x GPT-6 Astra. It matches Opus 5.5 on agentic terminal use and knowledge work: 64% on Terminal-Bench 4.0 vs Opus 5.5's 60%, and near-identical scores on AA-Briefcase, GDPval-AA, and AutomationBench-AA. It lags on factual knowledge (54% vs 66% accuracy on AA-Omniscience, but lower hallucination rate at 47% vs 59%) and scientific reasoning, trailing Opus 5.5 by ~6 points on Humanity's Last Exam and SciCode. Evaluations used a pre-release build with a structured-output bug that is fixed for launch; Anthropic expects performance to be at least as good. Context window remains 1M tokens with image and text input.
Heat over time
Heat now 8·Comparable peak 9（Sep 30 06:00）·Comparable change over 24 hours –
The trend only compares accounts observed without gaps, so its range may be smaller than the current heat. Hover or tap the chart for each hour; the left and right arrow keys step through it.