GPT-5.6 Sol on HealthBench Hard
rank 2 of 9 · updated August 16, 2026
On the 9-model HealthBench Hard board, GPT-5.6 Sol holds rank 2 with a score of 0.331. OpenAI's flagship 5.6-series model, built for its heaviest reasoning and agentic work. HealthBench Hard tests models on the 1,000 health conversations the frontier found hardest, with each response judged against its conversation's physician-written rubric and scored between 0 and 1.
Score and API facts
| rank | 2 of 9 |
|---|---|
| score | 0.331 |
| lab | OpenAI |
| context window | 1.1M tokens |
| API price per 1M tokens | $5.00 in / $30.00 out |
| license | proprietary |
| released | 2026-07-09 |
Where it sits
Muse Spark tops the board at 0.428, which puts GPT-5.6 Sol 0.097 off the lead. One place down is GPT-5.6 Terra at 0.327. Every row on the board comes out of one run, so a gap between two models is measured on the same conversations under the same grader.
What does GPT-5.6 Sol score on HealthBench Hard?
As of August 16, 2026, GPT-5.6 Sol scores 0.331 on HealthBench Hard, 2 of 9 models on the board.
What does GPT-5.6 Sol cost per million tokens?
OpenAI lists GPT-5.6 Sol at $5.00 per million input tokens and $30.00 per million output tokens.
Head to head
The pairings that earned a full page are linked below; the rest of the differences live in the score-difference matrix.
- 0.331 vs 0.428 · Muse Spark by 0.097
- 0.331 vs 0.327 · GPT-5.6 Sol by 0.004
- GPT-5.6 Sol vs GPT-5.6 Luna0.331 vs 0.320 · GPT-5.6 Sol by 0.011
- GPT-5.6 Sol vs GPT OSS 120B0.331 vs 0.300 · GPT-5.6 Sol by 0.031
- GPT-5.6 Sol vs GPT-5.3 Chat0.331 vs 0.259 · GPT-5.6 Sol by 0.072
- GPT-5.6 Sol vs GPT-5.5 Instant0.331 vs 0.229 · GPT-5.6 Sol by 0.102
- GPT-5.6 Sol vs GPT OSS 20B0.331 vs 0.108 · GPT-5.6 Sol by 0.223
- 0.331 vs 0.016 · GPT-5.6 Sol by 0.315
How the conversations are graded is on the methodology page, and how the subset was selected is on the benchmark page. The full ranking is on the leaderboard.