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Claude Sonnet 5 vs GPT-5.5
Of the 3 public leaderboards that rate both, Claude Sonnet 5 scores higher on 1 and GPT-5.5 on 2. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Claude Sonnet 5 is at 24.5 and GPT-5.5 at 66.7 (out of 100). On each maker's API, Claude Sonnet 5 costs $2 / $10 per 1M tokens (input / output) and GPT-5.5 $5 / $30.
Scores as published by each board; table composed November 10, 2026.
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Leaderboard by leaderboard
| Board | Claude Sonnet 5 | GPT-5.5 | Higher |
|---|---|---|---|
| LMArena Elo (community votes) | 1,539.2 | 1,511.9 | Claude Sonnet 5 |
| SimpleBench AVG@5 % (private set) | 60.6 | 76.9 | GPT-5.5 |
| Epoch AI Epoch Capabilities Index (ECI) · many benchmarks on one scale | 156.7 | 162.8 | GPT-5.5 |
Raw scores are each board's own scale, so compare within a row, not across rows. Full table: the bench index.
For coding
On the ArtificialWatch coding index, Claude Sonnet 5 is at 42.5 (#23 of 47) and GPT-5.5 at 38.4 (#29). Claude Sonnet 5 scores higher on 1 of the 2 coding boards that rate both and GPT-5.5 on 1.
| Coding board | Claude Sonnet 5 | GPT-5.5 |
|---|---|---|
| LMArena · Coding | 1,483.2 | 1,493.9 |
| Vals Vibe Code Bench | 81.3 | 69.8 |
Claude Sonnet 5 at a glance
- Developer
- Anthropic
- Status
- Live since June 30, 2026
- API price
- $2 input / $10 output per 1M tokens · Anthropic, claude-sonnet-5
- Context window
- 1M tokens
Shipped Jun 30.
GPT-5.5 at a glance
- Developer
- OpenAI
- Status
- Live since April 24, 2026
- API price
- $5 input / $30 output per 1M tokens · OpenAI, gpt-5.5
- Context window
- 1.05M tokens
Live.
Claude Sonnet 5 vs GPT-5.5: quick answers
Which is better, Claude Sonnet 5 or GPT-5.5?
It depends on what you measure. Of the 3 public leaderboards that rate both, Claude Sonnet 5 scores higher on 1 and GPT-5.5 on 2. Claude Sonnet 5's widest lead is on LMArena; GPT-5.5's widest lead is on SimpleBench. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Claude Sonnet 5 is at 24.5 and GPT-5.5 at 66.7 (out of 100).
Which is newer, Claude Sonnet 5 or GPT-5.5?
Claude Sonnet 5. It went live on June 30, 2026, 67 days after GPT-5.5 (April 24, 2026).
Which is cheaper, Claude Sonnet 5 or GPT-5.5?
Claude Sonnet 5 is cheaper on both input and output. On each vendor's own API, Claude Sonnet 5 is $2 input / $10 output per million tokens and GPT-5.5 is $5 input / $30 output per million tokens. GPT-5.5's rate rises for prompts over 272K tokens. Prices as published in the models.dev catalog, as of 2026-11-10.
Which has the bigger context window, Claude Sonnet 5 or GPT-5.5?
GPT-5.5, at 1.05M tokens against Claude Sonnet 5's 1M, as each vendor lists it.
How do Claude Sonnet 5 and GPT-5.5 compare for coding?
On the ArtificialWatch coding index, Claude Sonnet 5 is at 42.5 (#23 of 47) and GPT-5.5 at 38.4 (#29). Claude Sonnet 5 scores higher on 1 of the 2 coding boards that rate both and GPT-5.5 on 1.
Who makes Claude Sonnet 5 and GPT-5.5?
Claude Sonnet 5 is from Anthropic; GPT-5.5 is from OpenAI.
Where do these numbers come from?
Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed November 10, 2026). Boards measure different things, so raw scores are only comparable within a row.
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Also: the bench index · API pricing · what a workload costs on each · the wire