GPT-6 Luna on HealthBench Professional

rank 8 of 31 · updated September 30, 2026

GPT-6 Luna scores 0.608 on HealthBench Professional, rank 8 of 31 models on the board. HealthBench Professional scores models on 525 tasks drawn from real clinician conversations, graded criterion by criterion against physician-written rubrics on a 0 to 1 scale.

Result and API facts

rank	8 of 31
score	0.608
lab	OpenAI
context window	1.05M tokens
API price per 1M tokens	$0.10 in / $0.50 out
license	proprietary
source	GPT-6 Astra System Card - HealthBench (Deployment Safety Hub) (system card)
released	2026-09-22

Position in the field

The gap to the leader, GPT-6 Astra (Anthropic run) at 0.703, is 0.095. Directly above sits Claude Fable 5.1 at 0.621. Directly below sits GPT-6 Sol at 0.608. The scores on this page are compiled from published documents rather than from one controlled run, so a small gap between 2 models can reflect a difference in grader version, reasoning effort, or deployment setting as well as a difference in capability.

Source of this score

Read from GPT-6 Astra System Card - HealthBench (Deployment Safety Hub) (system card, OpenAI, 2026-09-03). Vendor-reported. Confidence: verified. Configuration: OpenAI; length-adjusted; maximum reasoning effort; 60.8 (61.2, 2119) (adjusted, raw, mean response characters).

Evaluation | GPT-5.5 | GPT-5.6 Sol | GPT-5.6 Terra | GPT-5.6 Luna | GPT-6 Astra | GPT-6 Sol | GPT-6 Luna HealthBench Professional length-adjusted | 51.8 (57.2, 3818) | 60.5 (64.1, 3228) | 57.7 (62.4, 3618) | 55.7 (59.8, 3389) | 64.7 (68.2, 3185) | 60.8 (59.5, 1573) | 60.8 (61.2, 2119)

Section 11.4.1, Table 29, HealthBench Professional length-adjusted, GPT-6 Luna column; September 22 correction. · full entry on the sources page

What does GPT-6 Luna score on HealthBench Professional?

GPT-6 Luna scores 0.608 on HealthBench Professional, which places it at rank 8 of 31 models on the board as of September 30, 2026. The number was read from GPT-6 Astra System Card - HealthBench (Deployment Safety Hub), listed on the sources page.

How much does GPT-6 Luna cost to run?

GPT-6 Luna is priced at $0.10 per million input tokens and $0.50 per million output tokens through OpenAI's API.

Head to head

Pairings with a dedicated comparison page are linked; every other difference is in the score-difference matrix.

GPT-6 Luna vs GPT-6 Astra (Anthropic run)
0.608 vs 0.703 · GPT-6 Astra (Anthropic run) by 0.095
GPT-6 Luna vs Claude Sonnet 5.5
0.608 vs 0.692 · Claude Sonnet 5.5 by 0.084
GPT-6 Luna vs Claude Fable 5
0.608 vs 0.660 · Claude Fable 5 by 0.052
GPT-6 Luna vs Claude Opus 5.5
0.608 vs 0.656 · Claude Opus 5.5 by 0.048
GPT-6 Luna vs GPT-6 Astra
0.608 vs 0.647 · GPT-6 Astra by 0.039
GPT-6 Luna vs Claude Fable 5 (September card)
0.608 vs 0.633 · Claude Fable 5 (September card) by 0.025
GPT-6 Luna vs Claude Fable 5.1
0.608 vs 0.621 · Claude Fable 5.1 by 0.013
GPT-6 Luna vs GPT-6 Sol
0.608 vs 0.608 · GPT-6 Sol by 0.000
GPT-6 Luna vs GPT-5.6 Sol
0.608 vs 0.605 · GPT-6 Luna by 0.003
GPT-6 Luna vs Claude Opus 5
0.608 vs 0.598 · GPT-6 Luna by 0.010
GPT-6 Luna vs Muse Spark 1.1
0.608 vs 0.593 · GPT-6 Luna by 0.015
GPT-6 Luna vs Claude Sonnet 5
0.608 vs 0.578 · GPT-6 Luna by 0.030
GPT-6 Luna vs GPT-5.6 Terra
0.608 vs 0.577 · GPT-6 Luna by 0.031
GPT-6 Luna vs Claude Opus 4.8 (Opus 4.8 grader)
0.608 vs 0.574 · GPT-6 Luna by 0.034
GPT-6 Luna vs Grok 4.7
0.608 vs 0.567 · GPT-6 Luna by 0.041
GPT-6 Luna vs Claude Opus 4.8
0.608 vs 0.558 · GPT-6 Luna by 0.050
GPT-6 Luna vs GPT-5.6 Luna
0.608 vs 0.557 · GPT-6 Luna by 0.051
GPT-6 Luna vs Muse Spark
0.608 vs 0.541 · GPT-6 Luna by 0.067
GPT-6 Luna vs GPT-5.6 Sol (August)
0.608 vs 0.540 · GPT-6 Luna by 0.068
GPT-6 Luna vs Claude Opus 4.7
0.608 vs 0.519 · GPT-6 Luna by 0.089
GPT-6 Luna vs GPT-5.5
0.608 vs 0.518 · GPT-6 Luna by 0.090
GPT-6 Luna vs Grok 4.6
0.608 vs 0.485 · GPT-6 Luna by 0.123
GPT-6 Luna vs GPT-5.4
0.608 vs 0.481 · GPT-6 Luna by 0.127
GPT-6 Luna vs GPT-5
0.608 vs 0.462 · GPT-6 Luna by 0.146
GPT-6 Luna vs GPT-5.2
0.608 vs 0.459 · GPT-6 Luna by 0.149
GPT-6 Luna vs Claude Sonnet 4.6
0.608 vs 0.442 · GPT-6 Luna by 0.166
GPT-6 Luna vs GPT-5.6 Luna (August)
0.608 vs 0.441 · GPT-6 Luna by 0.167
GPT-6 Luna vs GPT-5.1
0.608 vs 0.396 · GPT-6 Luna by 0.212
GPT-6 Luna vs GPT-5.5 Instant
0.608 vs 0.384 · GPT-6 Luna by 0.224
GPT-6 Luna vs MAI-Thinking-1
0.608 vs 0.350 · GPT-6 Luna by 0.258

Where the scores come from and how they are read is on the methodology page. The full ranking is on the leaderboard.