Head-to-head
Claude Sonnet 5 vs GPT-5.2: which AI model wins in 2026?
Claude Sonnet 5 ($15/1M out ($10 intro until 2026-08-31)) and GPT-5.2 ($14/1M out) are two of the most-used AI models in 2026. Across 5 community votes, Claude Sonnet 5 leads with 57% approval.
Quick verdict
On Reasoning, pick Claude Sonnet 5: the arena rates it 4.5/5 against 4/5 for GPT-5.2. On budget, GPT-5.2 wins: it starts at $14/1M out versus $15/1M out ($10 intro until 2026-08-31) for Claude Sonnet 5.
Line-by-line comparison
Strengths and weaknesses
Claude Sonnet 5
- 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
- First Sonnet with xhigh effort level and high-resolution vision (2576px images); adaptive thinking enabled by default
- Higher code-review precision than Sonnet 4.6 (38-40% vs 29%), producing fewer false-positive findings
- 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)
- Sampling parameters (temperature, top_p, top_k) removed; non-default values return a 400 error, breaking existing pipelines
- Launch sentiment on HN/Reddit was mixed: the '5' label was seen as overpromising, and stricter cybersecurity safeguards can refuse benign security-adjacent work
GPT-5.2
- 80.0% SWE-bench Verified and 55.6% SWE-Bench Pro at launch, near parity with Claude Opus 4.5 (80.9%)
- GDPval: ties or beats human professionals in 70.9% of comparisons, nearly double GPT-5.1's 38.8%
- Strong science and math: 92.4% GPQA Diamond (Thinking, 93.2% Pro) and 40.3% FrontierMath, state of the art at release
- 400K context with near-perfect MRCR v2 long-context retrieval up to 256K tokens
- 30% fewer hallucinations than GPT-5.1 (error rate on real ChatGPT queries down from 8.8% to 6.2%)
- Cheaper than its successors: $1.75/$14 per 1M vs $2.50/$15 (GPT-5.4) and $5/$30 (GPT-5.5)
- Speed is the top community complaint: extended thinking reported as low as ~4 tokens/s in ChatGPT, and Pro can think for a very long time and still fail
- Headline benchmark scores were obtained at xhigh reasoning effort, which consumes far more tokens and time than default settings
- Widely criticized personality regression vs GPT-5.1: Reddit users called it 'too corporate, too safe' and 'a step backwards' for chat and writing
- Coding lags Anthropic's line in head-to-head Elo comparisons (a later Opus 4.7 analysis cited a 144 Elo gap); no audio modality, no fine-tuning
- Already superseded as of mid-2026: OpenAI recommends GPT-5.5 and GPT-5.2 no longer appears on the main API pricing page
Cast your verdict
One recommendation per tool per gladiator. It reshapes the crowd score everyone sees.
The arena’s verdict on Claude Sonnet 5
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.
The arena’s verdict on GPT-5.2
Pick GPT-5.2 over GPT-5.1 for heavy reasoning, long-context, or agentic work: it nearly doubles GPT-5.1's GDPval win rate, cuts hallucinations 30%, and handles 400K contexts reliably. In mid-2026 it is mainly a value play, priced at $1.75/$14 versus $5/$30 for GPT-5.5 while staying competent on most professional tasks. Avoid it for latency-sensitive chat and creative writing, where users found it slow and flatter than GPT-5.1. Teams that want OpenAI's current frontier should pay up for GPT-5.5 instead.
What the crowd says
On Claude Sonnet 5
“Cheap per token, pricey per task. Independent tests had it near $2.29 a task vs $1.20 on 4.6, and at high effort it can out-cost Opus 4.8. It will not stop talking.”
“Terminal-Bench going 67 to 80 over Sonnet 4.6 matches what I see. My CI-fix agent went from constant babysitting to mostly hands-off overnight.”
“Matches Opus 4.8 on knowledge work at 60% of the price, and the intro $2/$10 window makes it silly value. My research agent runs on Sonnet 5 now, zero regrets.”
On GPT-5.2
“The thinking speed is brutal, I clocked something like 4 tok/s in ChatGPT on extended thinking. Pro will grind for ages and still whiff. Great scores, painful to actually use.”
“GDPval numbers are wild, it ties or beats human pros in 71% of comparisons. For science and math work (92.4 GPQA Diamond) it earned a spot in my stack.”
Keep comparing
Frequently asked questions
Is Claude Sonnet 5 better than GPT-5.2?
The crowd currently sides with Claude Sonnet 5: 57% recommend it, versus 50% for GPT-5.2 (5 votes). On Reasoning, Claude Sonnet 5 rates higher (4.5/5 vs 4/5). The right pick depends on your use case. The line-by-line comparison on this page breaks down pricing, key specs and arena ratings.
Which is cheaper, Claude Sonnet 5 or GPT-5.2?
GPT-5.2 is cheaper: it starts at $14/1M out, while Claude Sonnet 5 starts at $15/1M out ($10 intro until 2026-08-31).
How much do Claude Sonnet 5 and GPT-5.2 cost per 1M tokens?
Claude Sonnet 5: $3/1M in ($2 intro until 2026-08-31) per 1M input tokens, $15/1M out ($10 intro until 2026-08-31) per 1M output tokens. GPT-5.2: $1.75/1M in per 1M input tokens, $14/1M out per 1M output tokens.