GPT-6 Astra vs Claude Opus 5.5

GPT-6 and Claude Opus 5.5 at a glance

GPT-6 is an OpenAI model family with 3 variants (Astra, Sol and Luna) available in Quad Chat, with up to 1.05M tokens of context, image input, tool calling and adjustable reasoning. Claude Opus 5.5 is an Anthropic model available in Quad Chat, with up to 1M tokens of context, image input, tool calling and adjustable reasoning. This page compares specifications and plan availability from the Quad Chat model catalog. It does not publish benchmark scores, because quality depends on your task; the quickest fair test is to send the same prompt to both models in one Quad Chat conversation. Where a family has several variants, the head-to-head below uses the top variant (the one needing the highest plan, then the highest output price): GPT-6 Astra for GPT-6.

GPT-6 Astra vs Claude Opus 5.5

Top variant of each family, side by side. Lab: GPT-6 Astra OpenAI, Claude Opus 5.5 Anthropic. Plan needed: GPT-6 Astra Pro ($15/month), Claude Opus 5.5 Ultra ($40/month). Context window: GPT-6 Astra 1.05M tokens, Claude Opus 5.5 1M tokens. Max output: GPT-6 Astra 128K tokens, Claude Opus 5.5 128K tokens. API input price: GPT-6 Astra $10.00 per 1M, Claude Opus 5.5 $4.00 per 1M. API output price: GPT-6 Astra $50.00 per 1M, Claude Opus 5.5 $20.00 per 1M. Image input: GPT-6 Astra Yes, Claude Opus 5.5 Yes. Tool calling: GPT-6 Astra Yes, Claude Opus 5.5 Yes. Reasoning: GPT-6 Astra Yes, adjustable (low, medium, high, xhigh, max), Claude Opus 5.5 Yes, adjustable (low, medium, high, xhigh, max). Privacy lane: GPT-6 Astra Private Lane (Zero Data Retention), Claude Opus 5.5 Private Lane (Zero Data Retention).

Cheapest GPT-6 vs cheapest Claude Opus 5.5

The lowest-priced variant of each family, for everyday use. Lab: GPT-6 Luna OpenAI, Claude Opus 5.5 Anthropic. Plan needed: GPT-6 Luna Free, Claude Opus 5.5 Ultra ($40/month). Context window: GPT-6 Luna 1.05M tokens, Claude Opus 5.5 1M tokens. Max output: GPT-6 Luna 128K tokens, Claude Opus 5.5 128K tokens. API input price: GPT-6 Luna $0.10 per 1M, Claude Opus 5.5 $4.00 per 1M. API output price: GPT-6 Luna $0.50 per 1M, Claude Opus 5.5 $20.00 per 1M. Image input: GPT-6 Luna Yes, Claude Opus 5.5 Yes. Tool calling: GPT-6 Luna Yes, Claude Opus 5.5 Yes. Reasoning: GPT-6 Luna Yes, adjustable (low, medium, high, xhigh, max), Claude Opus 5.5 Yes, adjustable (low, medium, high, xhigh, max). Privacy lane: GPT-6 Luna Private Lane (Zero Data Retention), Claude Opus 5.5 Private Lane (Zero Data Retention).

Choose GPT-6 or Claude Opus 5.5

Each point below comes from a real difference in the catalog data. Choose GPT-6 if: You want a budget variant: GPT-6 Luna is the cheapest in its family at $0.10 in / $0.50 out, below Claude Opus 5.5 at $4.00 in / $20.00 out. You want to start on a lower plan: GPT-6 has a variant on the Free plan (no credit card), while Claude Opus 5.5 starts at Ultra ($40/month). You want top-tier access for less: GPT-6 Astra needs Pro ($15/month), while Claude Opus 5.5 needs Ultra ($40/month). You like choosing a size: GPT-6 comes in 3 variants (GPT-6 Astra, GPT-6 Sol and GPT-6 Luna), against 1. Choose Claude Opus 5.5 if: You want the lower API list price at the top tier: Claude Opus 5.5 lists at $4.00 in / $20.00 out against $10.00 in / $50.00 out for GPT-6 Astra, about 2.5× less per output token. Their context windows are within 10% of each other (1.05M and 1M tokens). Their longest replies are within 10% of each other (128K and 128K tokens). You do not have to choose: Quad Chat lets you switch between GPT-6 and Claude Opus 5.5 in the same conversation, or ask both at once and compare the answers.

Every GPT-6 and Claude Opus 5.5 variant

All selectable variants of both families. Click a header to sort. GPT-6: GPT-6 Astra (Pro), GPT-6 Sol (Pro), GPT-6 Luna (Free). Claude Opus 5.5: Claude Opus 5.5 (Ultra).

Frequently asked questions

Is GPT-6 or Claude Opus 5.5 cheaper?

At provider list prices, Claude Opus 5.5 is cheaper at the top tier ($4.00 in / $20.00 out against $10.00 in / $50.00 out per million tokens). API prices are the model provider's list prices per million tokens, shown for comparison only. Quad Chat plans have a flat monthly price and draw usage from shared credits, so you are not billed per token.

Which has the larger context window, GPT-6 or Claude Opus 5.5?

GPT-6 reaches 1.05M tokens, against 1M for Claude Opus 5.5, according to the model catalog Quad Chat routes through. Files, pasted text and earlier messages all count toward the window.

Which Quad Chat plan do I need for GPT-6 and Claude Opus 5.5?

GPT-6 starts on the Free plan, and its top variant, GPT-6 Astra, needs the Pro ($15/month) plan. Claude Opus 5.5 needs the Ultra ($40/month) plan. Plans are cumulative, and every plan shares one monthly credit balance (100 on Free up to 25,000 on Max).

Do GPT-6 and Claude Opus 5.5 support images, tools and reasoning?

GPT-6 Astra: image input yes, tool calling yes, reasoning yes. Claude Opus 5.5: image input yes, tool calling yes, reasoning yes. Other variants in each family can differ, as the variant table shows.

Can I use GPT-6 and Claude Opus 5.5 in the same chat?

Yes. In Quad Chat you can switch between models mid-conversation without losing your files or context, or send one prompt to both and compare the answers side by side, which is the most reliable way to decide between them for your own work. Side-by-side comparison is included on every plan.

Is GPT-6 or Claude Opus 5.5 more private in Quad Chat?

Both top variants run on the Private Lane, routed to providers under Zero Data Retention terms. Quad Chat does not train models on your conversations either way.