Claude Opus 4.8 vs GPT-5.5: A Comparison on Benchmarks and Price
Key Takeaways:
Claude Opus 4.8 leads coding benchmarks: It scores 88.6% on SWE-bench Verified and holds a 10-point edge on SWE-bench Pro.
GPT-5.5 still leads terminal-agent tasks: It keeps the crown for terminal-based speed and execution.
Opus 4.8 costs less: It is priced at $5/$25 per million tokens, compared with GPT-5.5 at $5/$30.
GPT-5.5 is more efficient: It uses around 30% fewer turns per task.
Anthropic and OpenAI have been racing to the top ever since AI started changing how we work. Their products, Claude and ChatGPT have been compared at every major turn.
Now, both of them have fresh releases on the table. Claude Opus 4.8,launched on May 28, 2026, and GPT-5.5 which arrived on April 23.
Both models are expensive, capable, and built to compete at the top end of AI. Still, neither wins everywhere. Each has clear strengths, and each leaves room for improvement.
This comparison uses verified benchmarks, pricing, and speed data to help you choose the right model for coding and agentic work.
Benchmarks: Who actually scores higher?
On raw capability, Opus 4.8 edges ahead. It tops the independent Artificial Analysis Intelligence Index at 61.4, about 1.2 points above GPT-5.5. The benchmark numbers tell the elaborate story:
On paper, these two are remarkably close. Opus 4.8 edges ahead on most coding and reasoning tests. GPT-5.5 claws back wins on terminal work and the gaps are usually a point or two.
Here’s what these benchmarks mean and why should care about them:
SWE-bench Verified: Measures how well a model resolves real GitHub issues. Opus 4.8 leads at 88.6% to 82.6%.
SWE-bench Pro: Tests harder multi-file fixes from active repositories. Opus 4.8 leads by over ten points, 69.2% to 58.6%.
Terminal-Bench: Tests command-line agent workflows. GPT-5.5 leads at 78.2% to 74.6%, while its Codex CLI reaches 83.4%.
GPQA Diamond: Tests graduate-level science reasoning. GPT-5.5 narrowly leads at 93.5% versus 92%.
Humanity’s Last Exam: Tests frontier reasoning across domains. Opus 4.8 leads slightly, 45.7% to 44.3%.
GDPval-AA: Measures agentic knowledge-work performance. Opus 4.8 scored 1,890 Elo, implying roughly a 67% head-to-head win rate over GPT-5.5.
Speed: Which one will make you wait less?
Speed is closer than what benchmarks suggest. Here’s how they compare:
OpenAI says that GPT‑5.5 matches GPT‑5.4 per-token latency in real-world serving, while performing at a much higher level of intelligence. In Codex, its optional Fast modegenerates tokens 1.5× faster at 2.5× the cost.
Anthropic counters with an Opus 4.8 Fast mode running at 2.5× speed and three times cheaper than fast mode on previous Claude models.
But the real-world catch is turns. “Turns” refers to the number of back-and-forth steps an AI agent takes to complete a task.
Artificial Analysis found Opus 4.8 still uses roughly 30% more turns per task. So even if Opus 4.8 generates quickly, it may still take more agent steps than GPT-5.5 to finish the task.
Cost: Which one will set you back more?
Pricing is close only at the short-context input level. In that regard, Claude Opus 4.8 and GPT-5.5 both charge $5 per million input tokens, but GPT-5.5 is costlier on output and becomes even more expensive in long-context sessions.
*Note: We have only considered standard pricing here. For more detailed pricing, refer to the company website.
For example, take 10 million tokens a day at a 70/30 input-output split. At short-context pricing, Opus 4.8 runs about $110/day, while GPT-5.5 runs about $125/day, making Opus 4.8 roughly 12% cheaper.
For long-context workloads, the difference becomes much larger. The same 70/30 split would cost about $110/day on Opus 4.8 versus $205/day on GPT-5.5.
The final bill may still vary by workload. GPT-5.5 uses fewer turns per task, so its cost per completed task can narrow that gap, especially for terminal-heavy agents.
How to make a choice?
There’s no universal winner, so don’t choose from benchmark tables alone. Pick one workflow, run both models on the same task, and measure accuracy, turns, latency, and final cost.
Choose GPT-5.5 if your team needs fast iteration in terminal-heavy or tool-heavy workflows. Its lower turn count can help agents move through repeated tasks faster.
Choose Claude Opus 4.8 if the work needs stronger reliability, deeper reasoning, or longer unattended runs. Its flatter pricing and coding accuracy make it safer for high-stakes production work.
For most teams, prototype on GPT-5.5, then move reliability-critical workflows to Opus 4.8 after testing.
FAQs on Claude Opus 4.8 vs GPT-5.5
Is Claude Opus 4.8 better than GPT-5.5?
Claude Opus 4.8 is stronger for coding accuracy, reasoning, reliability, and long-context cost. GPT-5.5 is better for terminal-heavy workflows and faster agent iteration.
Which model is cheaper, Claude Opus 4.8 or GPT-5.5?
Claude Opus 4.8 is cheaper in this comparison. Both start at $5 per million input tokens, but Opus 4.8 has lower output pricing and no long-context surcharge in the table.
Is GPT-5.5 faster than Claude Opus 4.8?
GPT-5.5 can be faster for agentic workflows because it uses fewer turns per task. Opus 4.8 may need more correction cycles, even when its final answer is stronger.
Which model should coding teams choose in 2026?
Coding teams should test both on real workflows. Use GPT-5.5 for terminal-heavy iteration, and use Claude Opus 4.8 for reliability-critical coding and long-running agent tasks.
Disclaimer: This article is AI-assisted content and may contain errors. All benchmark, pricing, and product details are based on Anthropic’s Claude Opus 4.8 announcement, OpenAI’s GPT-5.5 announcement, individual API pages, Artificial Analysis, Vals AI, and related benchmark pages accessed during research. Model performance, pricing, availability, context limits, and benchmark scores may change as providers update their systems.