# Claude Opus 5 vs Claude Sonnet 5 (2026): side-by-side comparison

Source: [GLAD-AI-TOR](https://glad-ia-tor.com) · Full page: https://glad-ia-tor.com/vs/claude-opus-5-vs-claude-sonnet-5
Arena: llm-models · Crowd scores are live visitor verdicts (one per person per tool, never paid, Bayesian-smoothed).

## At a glance

| | Claude Opus 5 | Claude Sonnet 5 |
|---|---|---|
| Price | $25/1M out | $15/1M out ($10 intro until 2026-08-31) |
| Crowd score | 63% (4 votes) | 57% (3 votes) |
| provider | Anthropic | Anthropic |
| contextWindow | 1M tokens | 1M tokens (128K max output) |
| priceIn | $5/1M in | $3/1M in ($2 intro until 2026-08-31) |
| priceOut | $25/1M out | $15/1M out ($10 intro until 2026-08-31) |
| modalities | text, vision | text, vision (image input, text output) |
| openWeights | no | no |
| reasoning (1-5) | 5 | 4.5 |
| coding (1-5) | 5 | 4.5 |
| writing (1-5) | 4 | 4.5 |
| speed (1-5) | 2 | 4 |
| valueForMoney (1-5) | 4 | 4.5 |

### Claude Opus 5

> Anthropic's July 2026 Opus refresh: near-Fable 5 intelligence at half the price, same $5/$25 as Opus 4.8

Strengths:
- Ranked #1 in composite intelligence across 190 models on Artificial Analysis at launch, and 43.3% on Frontier-Bench v0.1 vs 34.4% for GPT-5.6 Sol and 33.7% for Claude Fable 5
- 3.9x better than GPT-5.6 Sol on ARC-AGI-3 novel reasoning (30.2% vs 7.8%), and Elo 1861 on GDPval-AA v2 economic knowledge work, ahead of Fable 5 (1747)
- 79.2% on SWE-bench Pro, within a point of Fable 5 (80.0%) and 10 points above Opus 4.8 (69.2%), at half Fable's price; Cursor's co-founder calls it 'near Fable 5 intelligence at Opus speed and cost'
- Same $5/$25 pricing as Opus 4.8 with a bigger window: 1M context is now the default and only tier, with 128K max output and prompt caching from 512 tokens

Weaknesses:
- Notably slow and very verbose: 52.6 output tokens/s and 68 seconds to first token on Artificial Analysis, and it consumed ~100M output tokens during their eval vs a 63M median
- The verbosity is a real-world cost problem: CodeRabbit measured it reading ~50% more and writing ~65% more than reference frontier models per code-review call
- No actual price cut despite the 'cost-efficient' narrative: identical to Opus 4.8 ($5/$25), nearly GPT-5.6 money ($5/$30), and more than 2x comparable Gemini or Grok tiers

Verdict: Claude Opus 5 is the sane default of the Series 5 range: most of Fable 5's intelligence (and more than Fable on Frontier-Bench and GDPval) at exactly half the token price, with classifiers that trigger 85% less often. If you migrated workloads to Fable 5 for capability but resent the bill or the false-positive refusals, move them here; if you are still on Opus 4.8, the upgrade is 10 SWE-bench Pro points for free. The two honest reasons to look elsewhere: latency and verbosity. At 52.6 tokens/s with 68s to first token it is a poor fit for interactive UX, and its token appetite quietly inflates real costs beyond the sticker price, so budget-sensitive high-volume pipelines still belong on Sonnet 5, Gemini or DeepSeek. Keep Fable 5 only for the longest autonomous runs where its slight SWE-bench Pro edge compounds.

Full review: https://glad-ia-tor.com/tool/claude-opus-5 · Markdown: https://glad-ia-tor.com/tool/claude-opus-5.md

### Claude Sonnet 5

> Anthropic's most agentic Sonnet: near Opus 4.8 quality on coding and agents at $3/$15 with 1M context

Strengths:
- Large agentic gains over Sonnet 4.6: Terminal-Bench 2.1 80.4% vs 67.0%, OSWorld-Verified 81.2% vs 78.5%, SWE-bench Pro 63.2% vs 58.1%
- Matches Opus 4.8 on knowledge work (GDPval-AA v2: 1,618 vs 1,615) and nearly ties it on Humanity's Last Exam with tools (57.4% vs 57.9%) at 60% of Opus 4.8 pricing (40% during the intro window)
- 1M token context window and 128K max output; introductory pricing of $2/$10 per 1M tokens through Aug 31, 2026
- Persistent self-verifying agent behavior: hands-on reviews note it tests its own code and iterates on hard problems until solved, unlike Sonnet 4.6

Weaknesses:
- New tokenizer inflates token counts roughly 30% for the same text (1.0-1.35x per Anthropic; ~1.4x English, ~1.28x Python measured by Simon Willison), raising effective cost despite the unchanged sticker price
- Verbose and token-hungry: ~$2.29 per task vs ~$1.20 for Sonnet 4.6 in independent tests (ranked 101st of 161 for cost efficiency); at high effort cost-per-task can exceed Opus 4.8
- Measurably slower than Sonnet 4.6 on small routine edits and prone to over-engineering simple tasks (CodeRabbit hands-on review)

Verdict: Choose Sonnet 5 if you run coding, terminal or computer-use agents and want near Opus 4.8 quality at Sonnet prices, especially during the $2/$10 intro window; it is a strict upgrade over Sonnet 4.6 at low and medium effort. Budget for the new tokenizer and its verbosity: real per-task costs run well above Sonnet 4.6, and at the highest effort levels Opus 4.8 can be the better deal per solved task. Avoid it for latency-sensitive small edits or pipelines that rely on temperature and top_p, which now error. Sonnet 4.6 remains the pragmatic pick for high-volume tiny-diff workloads.

Full review: https://glad-ia-tor.com/tool/claude-sonnet-5 · Markdown: https://glad-ia-tor.com/tool/claude-sonnet-5.md

## More

Full llm-models ranking: https://glad-ia-tor.com/hall-of-fame/llm-models

---
This markdown version exists for AI assistants; the canonical page is https://glad-ia-tor.com/vs/claude-opus-5-vs-claude-sonnet-5