Claude Sonnet 5 vs GPT-5.2
Anthropic · US | OpenAI · US · Updated June 2026
Quick verdict
Pick Claude Sonnet 5 for agentic workflows that plan, use tools, and run autonomously or multi-step coding, debugging, and tool use. Pick GPT-5.2 for strong all-round reasoning or reliable structured output. On a tight budget at scale, GPT-5.2 is the value pick.
Claude Sonnet 5 (Anthropic) and GPT-5.2 (OpenAI) are two of the models people most often weigh against each other in 2026. Claude Sonnet 5 is anthropic's most agentic Sonnet, with near-Opus-4.8 performance at Sonnet prices; the default model on Free and Pro. GPT-5.2 is a capable GPT-5-generation all-rounder, now succeeded by GPT-5.5. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
- ▸Price: nearly identical — $2/$10 per 1M tokens vs $1.75/$14 per 1M tokens. Cost will not be the deciding factor here.
- ▸Context window: Claude Sonnet 5 holds 2.5× more — 1M (~1,500 pages) vs 400K (~600 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
- ▸Recency: Claude Sonnet 5 is the newer model by about 7 months (released June 30, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | Claude Sonnet 5 | GPT-5.2 |
|---|---|---|
| Provider | Anthropic (US) | OpenAI (US) |
| Released | June 30, 2026 | December 11, 2025 |
| Context window | 1M (~1,500 pages) | 400K (~600 pages) |
| Price (in/out) | $2/$10 per 1M tokens | $1.75/$14 per 1M tokens |
| Open weight? | No — API only | No — API only |
| Modalities | text, image, code | text, image, code |
| SWE-Bench Verified | Not published | Not published |
| MRCR v2 @ 1M | Not published | Not published |
Who wins what
Agentic workflows that plan, use tools, and run autonomously
Claude Sonnet 5
Anthropic's most agentic Sonnet, with near-Opus-4.8 performance at Sonnet prices; the default model on Free and Pro — and it carries the larger 1M context.
Multi-step coding, debugging, and tool use
Claude Sonnet 5
Anthropic's most agentic Sonnet, with near-Opus-4.8 performance at Sonnet prices; the default model on Free and Pro — and it is the newer of the two.
Everyday professional and knowledge work
Claude Sonnet 5
Claude Sonnet 5 lists everyday professional and knowledge work among its strengths; GPT-5.2 does not.
Strong all-round reasoning
GPT-5.2
A capable GPT-5-generation all-rounder, now succeeded by GPT-5.5 — and it runs cheaper at $1.75/$14 per 1M tokens.
Reliable structured output
GPT-5.2
GPT-5.2 lists reliable structured output among its strengths; Claude Sonnet 5 does not.
Broad ecosystem and tooling
GPT-5.2
GPT-5.2 lists broad ecosystem and tooling among its strengths; Claude Sonnet 5 does not.
Lowest cost at scale
GPT-5.2
At $1.75/$14 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
Claude Sonnet 5
Its 1M window is about 2.5× larger than GPT-5.2's 400K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ GPT-5.2
At $1.75/$14 per 1M tokens it undercuts Claude Sonnet 5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Claude Sonnet 5
Larger 1M window fits more in one prompt.
Anyone whose priority is agentic workflows that plan, use tools, and run autonomously
→ Claude Sonnet 5
It is specifically built for that.
Anyone whose priority is strong all-round reasoning
→ GPT-5.2
That is its strongest area.
Claude Sonnet 5: where it fits
Anthropic's most agentic Sonnet, with near-Opus-4.8 performance at Sonnet prices; the default model on Free and Pro. Released June 30, 2026 by Anthropic, it is built for agentic workflows that plan, use tools, and run autonomously, multi-step coding, debugging, and tool use, everyday professional and knowledge work, and long-document analysis and reasoning.
Its trade-offs are real: lower peak accuracy than Opus 4.8 on the hardest tasks, and an updated tokenizer that can use 1.0-1.35x more tokens for the same text. At $2 in / $10 out per million tokens, it sits in the mid price band.
GPT-5.2: where it fits
A capable GPT-5-generation all-rounder, now succeeded by GPT-5.5. Released December 11, 2025 by OpenAI, it is built for strong all-round reasoning, reliable structured output, broad ecosystem and tooling, and professional workflows.
Its trade-offs: superseded by GPT-5.5, and smaller context than flagships. At $1.75 in / $14 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Claude Sonnet 5 and GPT-5.2 overlap enough that the right pick depends on your specific job. GPT-5.2 costs less per token; Claude Sonnet 5 holds the larger context; and each leads in its own area — Claude Sonnet 5 for agentic workflows that plan, use tools, and run autonomously, GPT-5.2 for strong all-round reasoning. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Sonnet 5 and GPT-5.2 without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.
See pricingFrequently asked questions
Is Claude Sonnet 5 or GPT-5.2 better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 5 leans toward agentic workflows that plan, use tools, and run autonomously while GPT-5.2 leans toward strong all-round reasoning, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Sonnet 5 or GPT-5.2?
GPT-5.2 is cheaper — $2/$10 per 1M tokens vs $1.75/$14 per 1M tokens, roughly 1.1× apart on input.
Which has the bigger context window?
Claude Sonnet 5 — 1M vs 400K, about 2.5× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Sonnet 5 and GPT-5.2 together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 5, GPT-5.2 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Sonnet 5 or GPT-5.2?
Claude Sonnet 5 — released June 30, 2026, about 7 months after GPT-5.2.
Related comparisons
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.