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GPT-5.6 vs GPT-5.5
Of the 3 public leaderboards that rate both, GPT-5.6 scores higher on 2 and GPT-5.5 on 1. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, GPT-5.6 is at 48.2 and GPT-5.5 at 62.5 (out of 100). On each maker's API, GPT-5.6 costs $4 / $20 per 1M tokens (input / output) and GPT-5.5 $5 / $30.
Scores as published by each board; table composed November 12, 2026.
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Leaderboard by leaderboard
| Board | GPT-5.6 | GPT-5.5 | Higher |
|---|---|---|---|
| LMArena Elo (community votes) | 1,615.4 | 1,512.1 | GPT-5.6 |
| SimpleBench AVG@5 % (private set) | 71.7 | 76.9 | GPT-5.5 |
| Epoch AI Epoch Capabilities Index (ECI) · many benchmarks on one scale | 163 | 162.7 | GPT-5.6 |
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, GPT-5.6 is at 57.1 (#18 of 47) and GPT-5.5 at 38.4 (#27). GPT-5.6 scores higher on both coding boards that rate them.
| Coding board | GPT-5.6 | GPT-5.5 |
|---|---|---|
| LMArena · Coding | 1,495.2 | 1,493.9 |
| Vals Vibe Code Bench | 80.5 | 69.8 |
GPT-5.6 at a glance
- Developer
- OpenAI
- Status
- Live since July 9, 2026
- API price
- $4 input / $20 output per 1M tokens · OpenAI, gpt-5.6
- Context window
- 1.05M tokens
Live — Sol · Terra · Luna since Jul 9 · repriced Jul 30: Luna −80%, Terra −20%.
OpenAI Daybreak, explained: Blue vs Red access, GPT-5.6-Cyber, the $1B defender fund, and Sophos's 89-second cases
2026-10-12 · OpenAI Daybreak is OpenAI's program for putting its most cyber-capable models in the hands of approved defenders. On October 9 OpenAI published its first big customer result: Sophos says agents it built on Daybreak cut its average response time on those cases from about 38 minutes to about 89 seconds.
Three ChatGPT leaks in five hours were one release note — and the line none of them quoted is the real change
2026-08-06 · Three separate leaks landed in five hours claiming three separate ChatGPT changes: an upgraded GPT-5.6 Sol for Plus and Pro, a new reasoning slider rolling out, and unlimited chats coming for free users. All three are real.
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.
GPT-5.6 vs GPT-5.5: quick answers
Which is better, GPT-5.6 or GPT-5.5?
It depends on what you measure. Of the 3 public leaderboards that rate both, GPT-5.6 scores higher on 2 and GPT-5.5 on 1. GPT-5.6'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, GPT-5.6 is at 48.2 and GPT-5.5 at 62.5 (out of 100).
Which is newer, GPT-5.6 or GPT-5.5?
GPT-5.6. It went live on July 9, 2026, 76 days after GPT-5.5 (April 24, 2026).
Which is cheaper, GPT-5.6 or GPT-5.5?
GPT-5.6 is cheaper on both input and output. On each vendor's own API, GPT-5.6 is $4 input / $20 output per million tokens and GPT-5.5 is $5 input / $30 output per million tokens. GPT-5.6's rate rises for prompts over 272K tokens; GPT-5.5's rate rises for prompts over 272K tokens. Prices as published in the models.dev catalog, as of 2026-11-12.
Which has the bigger context window, GPT-5.6 or GPT-5.5?
Neither. Both take 1.05M tokens.
How do GPT-5.6 and GPT-5.5 compare for coding?
On the ArtificialWatch coding index, GPT-5.6 is at 57.1 (#18 of 47) and GPT-5.5 at 38.4 (#27). GPT-5.6 scores higher on both coding boards that rate them.
Who makes GPT-5.6 and GPT-5.5?
Both are from OpenAI.
Where do these numbers come from?
Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed November 12, 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