GPT-6 Sol vs Claude Opus 5.5 (2026): Price in India, Benchmarks & Which to Pick

OpenAI and Anthropic launched their new mid-to-top models on the same day, 22 September 2026: GPT-6 Sol (with a budget sibling, GPT-6 Luna) and Claude Opus 5.5. Per token, Sol is exactly half the price of Opus 5.5. On the benchmarks both companies have published so far, Opus 5.5 scores higher. This guide covers what each model costs in rupees, where you can actually use it in India, how the published numbers line up, and which one makes sense for your work.

By Shekhar Chandran | Published 27 September 2026 | 9 min read | Pricing and benchmarks verified from OpenAI’s “Introducing GPT-6 Sol and Luna” post and Anthropic’s Claude Opus 5.5 announcement, cross-checked against TechCrunch, MacRumors and the GitHub Changelog.

📅 27 September 2026 · 🕐 9 min read · 🗂️ AI Updates

This page covers:

• What GPT-6 Sol, GPT-6 Luna and Claude Opus 5.5 are, and what each one replaces
• API pricing in dollars and rupees, with a worked monthly cost example
• The benchmark numbers both companies published, and why they can’t all be compared directly
• Where Indian users can access each model (ChatGPT, Claude, GitHub Copilot, API)
• Which one to pick for coding, agents, high-volume tasks and everyday use

This page does not cover: GPT-6 Astra, OpenAI’s top model launched on 3 September. That one is in our ChatGPT Astra (GPT-6) review. Claude subscription plans in depth are covered in our Claude AI Pricing India guide.

Jump to a Section

1. What launched on 22 September?
2. GPT-6 Sol vs Claude Opus 5.5: price in dollars and rupees
3. What do the benchmarks actually show?
4. Where can you use each model in India?
5. Which one should you pick?
6. AIInsider Verdict
7. Quick Answers

What launched on 22 September?

GPT-6 Sol is OpenAI’s new workhorse model for “complex tasks including coding,” according to TechCrunch. It replaces GPT-5.6 Sol and, per OpenAI, was built “using methods similar to Astra’s.” OpenAI’s headline claim is reliability: Sol makes “about half as many mistakes” as GPT-5.6 Sol.

GPT-6 Luna is the cheap, fast sibling. OpenAI positions it for “high-volume tasks with a clear goal, like summarizing documents, extracting information, or answering quick questions.” It replaces GPT-5.6 Luna.

Claude Opus 5.5 is Anthropic’s new Opus model and the first release in the Claude 5.5 family. Anthropic says it “leads in agentic coding and knowledge work,” generates output more than 30% faster than Opus 5, and “costs 40% less to run than Opus 5 on typical workloads.” Part of that saving comes from a lower list price. The rest comes from a lower default effort setting (medium instead of high), so it uses fewer tokens per task.

Here is the part most launch coverage glossed over: the two companies were not comparing their models to the same things. OpenAI benchmarked Sol against Claude Opus 5, not Opus 5.5, because Opus 5.5 launched the same day. So any “Sol beats Claude” headline you saw is about the older model.

GPT-6 Sol vs Claude Opus 5.5: price in dollars and rupees

API prices below are per million tokens. Rupee figures use the live mid-market rate of ₹95.78 per $1 (Wise, checked 27 September 2026). GST and card-conversion fees are not included.

Sources: OpenAI and Anthropic launch posts for pricing. Context and output limits are from independent spec write-ups (Kingy AI, Digital Applied), because OpenAI’s announcement does not state a context window.

A worked example. Take an app that sends 10 million input tokens and gets back 2 million output tokens a month, a realistic load for a small customer-support bot or internal coding assistant:

• GPT-6 Luna: $2 a month, about ₹192
• GPT-6 Sol: $40 a month, about ₹3,831
• Claude Opus 5.5: $80 a month, about ₹7,662

That doubling is per token, not per finished task. If Opus 5.5 finishes a job in fewer steps or with fewer retries, the real gap shrinks. Anthropic’s lower default effort setting is designed to do exactly that. Measure your own workload before trusting either company’s cost claims, including the “40% less” line.

“Sol is the cheaper model. Opus 5.5 is the stronger one on the published numbers. Whether it’s worth twice the price depends on how often a cheaper model’s mistake costs you a re-run.”

What do the benchmarks actually show?

Every number below is vendor-reported. OpenAI tested Sol, and Anthropic tested Opus 5.5. No independent lab has run the two side by side yet. Only two benchmarks appear in both companies’ results with comparable setups:

Opus 5.5 leads on both. Beyond these two, each company reported benchmarks the other didn’t:

• Opus 5.5 only: Terminal-Bench 4.0 at 66.4% (GPT-6 Astra scored 57.9%), GDPval-AA at 1846 Elo, CursorBench 4.0 at 57.8%.
• Sol only: DeepSWE v1.1 at 68.8% (Luna: 66.6%), and Agents’ Last Exam at 56.4%.
• Where Opus 5.5 trails: by Anthropic’s own table, it is behind GPT-6 Astra on AutomationBench (40.0% vs 41.4%) and Terminal-Bench-Science (58.7% vs 64.6%). Independent tester Vals AI also measured a 13.8-point drop on its MedCode benchmark compared with Opus 5.

One number to ignore: both companies quote “OSWorld 2.0” (Sol 60.5%, Opus 5.5 81.8%). OpenAI’s figure is from the offline version, and Anthropic’s is labelled a partial run. Those setups are different, so the 21-point gap doesn’t show which model is better at using a computer.

Where Sol has a clear edge is cost per task. OpenAI reports $0.27 per AutomationBench task for Sol, and says Opus 5 cost 11.1× more for a lower score. That comparison is against Opus 5, not 5.5, but even after Opus 5.5’s lower price and effort, Sol will very likely stay the cheaper model per task.

My take: launch-week benchmark tables from the companies themselves are marketing with numbers attached. That doesn’t make them false, but each lab picks the tests where it looks good. What I trust more is the pattern across both sets of results: Anthropic keeps leading on long, multi-step coding and agent work, and OpenAI keeps winning on price. The same pattern showed up with Opus 5 and GPT-5.6, so I’d expect it to hold in independent tests too. I’ll update this piece once independent results are published.

Where can you use each model in India?

Access is where these two differ most for ordinary users. Opus 5.5 is available in the normal Claude app. Sol is not yet available in standard ChatGPT chat.

ChatGPT Plus India price per the regional tracker OpenTheRank. The Claude Pro INR price is Anthropic’s official India pricing, which includes GST.

🇮🇳 Students and ChatGPT Free/Go users: GPT-6 Luna is the one new model you can use at no cost, but only in the ChatGPT desktop app for now, not on the phone app or website. If you mostly summarise PDFs, notes or long documents, it’s worth installing the desktop app.

🇮🇳 Indian startups and developers: both APIs bill in US dollars, so the rupee cost moves with the exchange rate, and GST applies on top for most businesses. At Sol’s price, a prototype you would have kept on a cheaper model last year can now run on a frontier-class model for a few thousand rupees a month.

Which one should you pick?

• High-volume, simple tasks (summaries, data extraction, classification, support-ticket triage): GPT-6 Luna. At ₹47.89 per million output tokens, a more expensive model rarely pays for itself on this kind of work.
• Everyday coding help and agents on a budget: GPT-6 Sol. It costs half as much per token, and on its own figures it matches Opus 5 on OSWorld 2.0 while beating it on AutomationBench.
• Long, multi-step coding and agent work where a failed run is expensive (large refactors, terminal-heavy automation, Claude Cowork tasks): Claude Opus 5.5. It leads on the two benchmarks both labs report, and on Terminal-Bench 4.0.
• You just want the better chat assistant for ₹2,000 a month: right now that’s Claude Pro, simply because Opus 5.5 works in the normal Claude app, while Sol is limited to ChatGPT’s Work and Codex modes. If OpenAI brings Sol to regular chat, that changes.

Developers moving to Opus 5.5 should know about four breaking changes. Extended thinking can no longer be switched off. tool_choice: "any" now returns an error. Thinking blocks can’t be replayed after a system-prompt change. The older computer_20251124 tool has been replaced. Test before switching production traffic.

AIInsider Verdict

GPT-6 Sol is the better deal. Claude Opus 5.5 is the stronger model. On the only two benchmarks both labs report, Opus 5.5 leads by 5 to 7 points, and it adds a strong Terminal-Bench 4.0 score. Sol’s advantage is price: exactly half per token, and likely much less per task. For most Indian developers, that makes Sol the sensible default, with Opus 5.5 kept for the jobs where a mistake costs more than the tokens.

What we liked:

• Real price cuts on both sides: 50% on Sol and Luna, 20% list (and around 40% in practice, per Anthropic) on Opus 5.5
• GPT-6 Luna brings a new model to free ChatGPT users
• Opus 5.5 works in the normal Claude app from day one, with no special mode needed

What holds them back:

• No independent side-by-side tests yet. Every comparison figure here is vendor-reported.
• Sol is limited to ChatGPT’s Work and Codex modes for now, and Luna to the desktop app for free users
• Opus 5.5’s breaking API changes mean real migration work for existing Claude integrations
• Neither company offers rupee-denominated API pricing

My recommendation: if you’re building on a budget of under ₹5,000 a month in API spend, start on GPT-6 Sol and route only your hardest tasks to Opus 5.5. If you’re choosing one ₹2,000/month subscription for personal work today, choose Claude Pro. Revisit that once Sol is available in regular ChatGPT chat.

Quick Answers

When were GPT-6 Sol and Claude Opus 5.5 released?
Both launched on 22 September 2026. OpenAI released GPT-6 Sol and GPT-6 Luna, and Anthropic released Claude Opus 5.5 on the same day.

Is GPT-6 Sol cheaper than Claude Opus 5.5?
Yes. GPT-6 Sol costs $2 per million input tokens and $10 per million output tokens, exactly half of Claude Opus 5.5’s $4 and $20. At ₹95.78 per dollar, that is about ₹958 versus ₹1,916 per million output tokens.

Which is better for coding, GPT-6 Sol or Claude Opus 5.5?
On the benchmarks both companies published, Claude Opus 5.5 scores higher: 54.4% vs 49.3% on FrontierCode v1.1, and 40.0% vs 33.2% on AutomationBench 1.0.6. These are vendor-reported figures, not independent head-to-head tests.

Can I use GPT-6 Luna for free in India?
Yes. OpenAI made GPT-6 Luna available to ChatGPT Free and Go users, but only in the ChatGPT desktop app at launch.

Is Claude Opus 5.5 available on Claude Pro?
Yes. Opus 5.5 is available to Claude Pro, Max and Team subscribers. Claude Pro costs ₹2,000 a month in India when billed annually, including GST.

Related Articles

• ChatGPT Astra (GPT-6) Review: the top of OpenAI’s GPT-6 lineup, above Sol and Luna.
• Claude Opus 5 Review India: the model Opus 5.5 replaces, and the one OpenAI actually benchmarked against.
• Claude AI in India: The Complete 2026 Guide: every Claude model and plan in one place.
• Claude AI Pricing India 2026: official INR prices for Pro and Max.
• GitHub Copilot Review 2026: where you can use both new models inside your editor.
• Claude vs ChatGPT 2026: the broader case for each assistant.

Published 27 September 2026. Pricing and benchmark figures verified from OpenAI’s “Introducing GPT-6 Sol and Luna” and Anthropic’s Claude Opus 5.5 announcement (both 22 September 2026), cross-checked against TechCrunch, MacRumors, the GitHub Changelog, Vellum and Digital Applied. Rupee conversions use Wise’s mid-market rate of ₹95.78/$1, checked 27 September 2026. All benchmark figures are vendor-reported. AIInsider.in is independent and not affiliated with OpenAI or Anthropic.