GPT-5.5 vs Claude Opus 4.8
Side-by-side comparison of pricing, context window, modalities, licensing, and strengths — with practical guidance on which model fits which workload.
| Spec | GPT-5.5 | Claude Opus 4.8 |
|---|---|---|
| Provider | OpenAI | Anthropic |
| Context window | 1M tokens | 1M tokens |
| Input price (per 1M tokens) | $5.00 | $5.00 |
| Output price (per 1M tokens) | $30.00 | $25.00 |
| Example workload (10M in + 2M out) | $110.00 / month | $100.00 / month |
| Modalities | text, image, audio, code | text, image, code |
| Knowledge cutoff | Not disclosed | Not disclosed |
| Release date | 2026 | 2026 |
| License | Proprietary | Proprietary |
| Strengths | Flagship reasoning, Agentic tool use, Multimodal, Coding | Long-horizon agents, Coding, Knowledge work, Clear writing |
| Open weights | No | No |
Verdict
The 2026 flagship duel. Both models offer roughly 1M-token context windows and 128K output, but their pricing philosophies differ: Claude Opus 4.8 charges $5/$25 per million tokens flat, while GPT-5.5 costs $5/$30 — and bills prompts beyond 272K input tokens at 2× input / 1.5× output for the entire session, which matters enormously for long-context workloads. GPT-5.5 counters with native audio support and OpenAI’s vast ecosystem; Opus 4.8 is renowned for long-horizon agentic coding runs and clear, warm long-form writing.
When to choose GPT-5.5
Pick GPT-5.5 for audio-in workflows, the broadest third-party tooling ecosystem, and OpenAI-stack compatibility.
When to choose Claude Opus 4.8
Pick Claude Opus 4.8 for overnight agentic coding runs, long-document work without the long-context surcharge, and publication-quality writing.
Prices and specs reflect published provider information and change frequently — always confirm on the provider's pricing page before committing to a workload.
About
This page compares GPT-5.5 (OpenAI) and Claude Opus 4.8 (Anthropic) side by side across the specs that actually drive a model decision: API pricing per million tokens, context window size, supported modalities, licensing and open-weights status, knowledge cutoff, and headline strengths. A worked example projects the monthly cost of a typical workload (10M input + 2M output tokens) on each model, and an editorial verdict summarises when to choose which. Spec data comes from the same registry that powers our full model comparison table, so figures stay consistent across the site.
How to use
- 1 Scan the spec table for the head-to-head numbers — pricing, context window, modalities, license, and strengths for GPT-5.5 and Claude Opus 4.8.
- 2 Check the example-workload row to see what a realistic monthly volume costs on each model.
- 3 Read the verdict and the two "when to choose" cards to map each model to your use case.
- 4 Use the FAQ for quick answers on price, context window, and self-hosting.
- 5 Estimate your own numbers with the AI cost calculator and token counter linked at the bottom, or jump to a related comparison.
- Which is cheaper: GPT-5.5 or Claude Opus 4.8?
- Claude Opus 4.8 is cheaper per token: $5.00 input / $25.00 output per 1M tokens, versus $5.00 / $30.00 for GPT-5.5. Actual costs depend on your input-to-output ratio — try the AI cost calculator for your own numbers.
- Which has the larger context window?
- Both models offer roughly the same 1M-token context window, so raw capacity won't be the deciding factor — check instead whether either provider charges premium rates for long prompts.
- Can I self-host either model?
- No — both models are proprietary and available only through their providers' APIs or cloud platforms.
- How should I test which model is better for my use case?
- Benchmarks are a starting point, not an answer. Run both models on 20–50 examples of your real task and compare outputs blind. Use our token counter to estimate prompt sizes and the cost calculator to project monthly spend before committing.
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