GPT-5.5 vs Claude Opus 4.8
Side-by-side comparison of API pricing, specs, benchmarks, and capabilities
| Specification |
by OpenAI
|
by Anthropic
|
|---|---|---|
| Overview | ||
| Status | Current flagship | Current flagship |
| Released | Nov 15, 2025 | May 28, 2026 |
| Pricing per million tokens | ||
| Input | $5.00/Mtok | $5.00/Mtok |
| Output | $30.00/Mtok | $25.00/Mtok |
| Blended avg | $11.25/Mtok | $10.00/Mtok |
| Cached input | $0.500/Mtok | $0.500/Mtok |
| Specifications | ||
| Context window | 1M tokens | 1M tokens |
| Parameters | Proprietary | Proprietary |
| Speed (TPS) | — | — |
| Modalities | ||
| Input |
textimageaudio
|
textimage
|
| Benchmarks source: Vellum LLM Leaderboard | ||
| Avg benchmark score | 75 | 81.3 |
| Perf / dollar | 6.7 | 8.1 |
| GPQA Diamond | 93.6 | 93.6 |
| Terminal-Bench 2.1 | 82.7 | 74.6 |
| MCP Atlas | 75.3 | 82.2 |
| OSWorld-Verified | 78.7 | 83.4 |
| Humanity's Last Exam | 41.4 | 57.9 |
| HumanEval | 58.6 | 88.6 |
| AutoBench | 12.9 | 15.5 |
| SWE-Bench Verified | — | 88.6 |
| BrowseComp | 84.4 | — |
| ARC-AGI 2 | 85 | — |
| Independent composite scores each on its own scale — not part of the average above | ||
| AA Intelligence Index | 56.3 | 57.3 |
| AA Agentic Index | 47.4 | 49.4 |
| AA-Omniscience Index (−100–100) | 20.5 | 28.8 |
| GDPval-AA v2 | 1491.1 ELO | 1588.3 ELO |
| LMSYS Chatbot Arena | 1476.7 ELO | 1473.6 ELO |
| Providers | ||
| Available from |
OpenAI — $5.00/$30.00/Mtok
|
Anthropic — $5.00/$25.00/Mtok
|
Cost at scale
1M tokens · 50/50 input/output| Volume | GPT-5.5 | Claude Opus 4.8 | Savings |
|---|---|---|---|
| 1M tokens | $11.25 | $10 | $1.25 (11.1%) |
| 10M tokens | $112.5 | $100 | $12.5 (11.1%) |
| 100M tokens | $1125 | $1000 | $125 (11.1%) |
| 1000M tokens | $11250 | $10000 | $1250 (11.1%) |
When to pick which
distilled from the pricing and spec data above- this pairing gives GPT-5.5 no edge on price, context, cache discount, or measured performance — pick it only for qualitative fit (ecosystem, compliance, model behavior on your prompts)
- cost dominates: $10.00/Mtok blended vs $11.25 — 11.1% less on the same 50/50 token mix
- raw capability matters more than price: 81.3 vs 75 average benchmark score
The cheaper option here — Claude Opus 4.8 costs $10.00/Mtok blended on Anthropic.
Summary
GPT-5.5 by OpenAI costs $5.00/Mtok input and $30.00/Mtok output, with a 1M-token context window. It supports text, image, audio input.
Claude Opus 4.8 by Anthropic costs $5.00/Mtok input and $25.00/Mtok output, with a 1M-token context window. It supports text, image input.
On a blended cost basis, Claude Opus 4.8 is 11.1% cheaper than GPT-5.5.
On benchmarks, Claude Opus 4.8 scores higher (81.3 vs 75) on average. In terms of value, Claude Opus 4.8 has better performance per dollar (8.1 vs 6.7).
Note: Pricing is per million tokens. Actual costs vary with usage patterns, prompt caching, and batch discounts. Always verify against official provider pricing pages.