GPT-6.1 Sol vs Claude Opus 5.5
Official OpenAI and Anthropic API prices and LMArena scores, checked 2026-10-18. Add up to 2 more models to compare 4.
GPT-6.1 Sol costs less; Claude Opus 5.5 wins more LMArena tasks.
GPT-6.1 Sol is 2x cheaper on input and output. Claude Opus 5.5 scores 82 points higher for creative writing; GPT-6.1 Sol scores 3 points higher for vision. Across 7 shared LMArena tasks, Claude Opus 5.5 leads 6 to 1. A medium month (20M input + 5M output tokens) costs $90 on GPT-6.1 Sol and $180 on Claude Opus 5.5.
- Pick GPT-6.1 Sol if you want the lower bill ($90 vs $180 for a medium month), you care most about vision (+3) or you reuse long prompts (cached input $0.10 vs $0.20).
- Pick Claude Opus 5.5 if you care most about creative writing (+82), chat (+42) and roleplay (+19).
Medium: 20M input + 5M output tokens a month at list price (short-context rate, no caching or batch discounts).
Marked side is better: lower for prices, higher for context and scores. Bars are scaled to the larger of the two.
| Spec | GPT-6.1 Sol | Claude Opus 5.5 |
|---|---|---|
| Price per 1M tokens | ||
| Input | $2 | $4 |
| Cached input | $0.10 | $0.20 |
| Output | $10 | $20 |
| Blend 3:1 | $4 | $8 |
| Sample month, medium | $90 | $180 |
| Context | ||
| Context window | 1.05M tokens | 1M tokens |
| Quality (LMArena, out of 100) | ||
| Coding | 82/100 #4 of 23 | 100/100 #1 of 23 |
| Chat | 30/100 #10 of 25 | 72/100 #3 of 25 |
| Creative writing | 18/100 #12 of 25 | 100/100 #1 of 25 |
| Roleplay and characters | 15/100 #11 of 25 | 34/100 #4 of 25 |
| Reasoning and math | 39/100 #12 of 24 | 53/100 #6 of 24 |
| Vision | 85/100 #2 of 21 | 82/100 #3 of 21 |
| Long documents | Not ranked | Not ranked |
| Cheap bulk and agents | 84/100 #4 of 23 | 100/100 #1 of 23 |
| Details | ||
| Provider | OpenAI | Anthropic |
| API model id | gpt-6.1-sol | claude-opus-5.5 |
| Notes | Prompts up to 272K. Longer prompts cost $4 in, $15 out. | 5-minute cache writes $5. |
| Sources | ||
| Last checked | 2026-10-18 | 2026-10-18 |
| Official pricing | OpenAI pricing | Anthropic pricing |
Plans from data checked hourly against each vendor's official pricing page. Vendors state limits in different units, so we quote them as published. Team and enterprise plans are per seat.
API prices in USD per 1M tokens from each provider's official pricing page. Blend 3:1 = (3 x input + output) / 4. Sample month = stated input and output tokens at the list price, no caching. Quality: relative score out of 100 on each LMArena leaderboard (100 = top model we price on that board, n/a = not ranked there), data licensed CC BY 4.0. See how we pick.
Where each one ranks on LMArena
Relative score out of 100 on each leaderboard (100 = the top model we price there), with the rank among the models from our API price table that appear on that board.
- Coding (Code Arena): GPT-6.1 Sol #4 of 23 (82/100), Claude Opus 5.5 #1 of 23 (100/100)
- Chat (Text Arena): GPT-6.1 Sol #10 of 25 (30/100), Claude Opus 5.5 #3 of 25 (72/100)
- Creative writing (Text Arena creative writing): GPT-6.1 Sol #12 of 25 (18/100), Claude Opus 5.5 #1 of 25 (100/100)
- Roleplay and characters (Text Arena multi-turn): GPT-6.1 Sol #11 of 25 (15/100), Claude Opus 5.5 #4 of 25 (34/100)
- Reasoning and math (Text Arena math): GPT-6.1 Sol #12 of 24 (39/100), Claude Opus 5.5 #6 of 24 (53/100)
- Vision (Vision Arena): GPT-6.1 Sol #2 of 21 (85/100), Claude Opus 5.5 #3 of 21 (82/100)
- Long documents (Document Arena): GPT-6.1 Sol not ranked, Claude Opus 5.5 not ranked
- Cheap bulk and agents (Agent Arena): GPT-6.1 Sol #4 of 23 (84/100), Claude Opus 5.5 #1 of 23 (100/100)
Pricing details from the official pages
GPT-6.1 Sol lists $2 input, $10 output, $0.10 cached input per 1M tokens on OpenAI pricing. Claude Opus 5.5 lists $4 input, $20 output, $0.20 cached input per 1M tokens on Anthropic pricing. Prices checked 2026-10-18.
- GPT-6.1 Sol: Prompts up to 272K. Longer prompts cost $4 in, $15 out.
- Claude Opus 5.5: 5-minute cache writes $5.
Sample monthly bill at list price, no caching: Light (2M input + 0.5M output tokens): $9 vs $18. Medium (20M input + 5M output tokens): $90 vs $180. Heavy (200M input + 50M output tokens): $900 vs $1,800.
FAQ
Is GPT-6.1 Sol cheaper than Claude Opus 5.5?
GPT-6.1 Sol costs $2 input and $10 output per 1M tokens; Claude Opus 5.5 costs $4 and $20. For a medium month (20M input + 5M output tokens) GPT-6.1 Sol is cheaper: $90 vs $180.
Which is better for coding, GPT-6.1 Sol or Claude Opus 5.5?
On LMArena's Code Arena GPT-6.1 Sol scores 82/100 (#4 of 23) and Claude Opus 5.5 100/100 (#1 of 23), so Claude Opus 5.5 is ahead by 18 points.
Which has the bigger context window?
GPT-6.1 Sol: 1.05M tokens. Claude Opus 5.5: 1M tokens. Long prompts can cost more; see the pricing notes above.
How much do GPT-6.1 Sol and Claude Opus 5.5 cost per month?
Light (2M input + 0.5M output tokens): $9 vs $18. Medium (20M input + 5M output tokens): $90 vs $180. Heavy (200M input + 50M output tokens): $900 vs $1,800. Pick your own token counts in the plan vs API calculator.
Where do these numbers come from?
Prices come from each provider's official pricing page, checked daily. Quality is the relative score on the LMArena leaderboard dataset, licensed CC BY 4.0. Where a model is not ranked we show n/a.
Sources
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