GPT-5.6 Terra on HealthBench Professional

rank 14 of 31 · updated September 30, 2026

GPT-5.6 Terra scores 0.577 on HealthBench Professional, rank 14 of 31 models on the board. The balanced middle tier of the GPT-5.6 family, between Sol and Luna. 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	14 of 31
score	0.577
lab	OpenAI
context window	1.05M tokens
API price per 1M tokens	$2.00 in / $12.00 out
license	proprietary
source	GPT-5.6 System Card (system card)
released	2026-07-09

Position in the field

The gap to the leader, GPT-6 Astra (Anthropic run) at 0.703, is 0.126. Directly above sits Claude Sonnet 5 at 0.578. Directly below sits Claude Opus 4.8 (Opus 4.8 grader) at 0.574. 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-5.6 System Card (system card, OpenAI, 2026-07-09). Vendor-reported. Confidence: verified. Configuration: length-adjusted, max reasoning effort (62.4 unadjusted, 3,618 mean response chars); GPT-5.6 system card Table 6, column GPT-5.6-TERRA..

HealthBench Professional length-adjusted 46.2 (51.0, 3616) 39.6 (48.0, 4863) 45.9 (50.0, 3400) 48.1 (51.9, 3308) 51.8 (57.2, 3818) 60.5 (64.1, 3228) 57.7 (62.4, 3618) 55.7 (59.8, 3389)

Section 5.1 HealthBench, Table 6 (reported as length-adjusted score (unadjusted, mean response length in characters)), column GPT-5.6-TERRA · 1 corroborating document · full entry on the sources page

What does GPT-5.6 Terra score on HealthBench Professional?

GPT-5.6 Terra scores 0.577 on HealthBench Professional, which places it at rank 14 of 31 models on the board as of September 30, 2026. The number was read from GPT-5.6 System Card, listed on the sources page.

How much does GPT-5.6 Terra cost to run?

GPT-5.6 Terra is priced at $2.00 per million input tokens and $12.00 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-5.6 Terra vs GPT-6 Astra (Anthropic run)
0.577 vs 0.703 · GPT-6 Astra (Anthropic run) by 0.126
GPT-5.6 Terra vs Claude Sonnet 5.5
0.577 vs 0.692 · Claude Sonnet 5.5 by 0.115
GPT-5.6 Terra vs Claude Fable 5
0.577 vs 0.660 · Claude Fable 5 by 0.083
GPT-5.6 Terra vs Claude Opus 5.5
0.577 vs 0.656 · Claude Opus 5.5 by 0.079
GPT-5.6 Terra vs GPT-6 Astra
0.577 vs 0.647 · GPT-6 Astra by 0.070
GPT-5.6 Terra vs Claude Fable 5 (September card)
0.577 vs 0.633 · Claude Fable 5 (September card) by 0.056
GPT-5.6 Terra vs Claude Fable 5.1
0.577 vs 0.621 · Claude Fable 5.1 by 0.044
GPT-5.6 Terra vs GPT-6 Luna
0.577 vs 0.608 · GPT-6 Luna by 0.031
GPT-5.6 Terra vs GPT-6 Sol
0.577 vs 0.608 · GPT-6 Sol by 0.031
GPT-5.6 Terra vs GPT-5.6 Sol
0.577 vs 0.605 · GPT-5.6 Sol by 0.028
GPT-5.6 Terra vs Claude Opus 5
0.577 vs 0.598 · Claude Opus 5 by 0.021
GPT-5.6 Terra vs Muse Spark 1.1
0.577 vs 0.593 · Muse Spark 1.1 by 0.016
GPT-5.6 Terra vs Claude Sonnet 5
0.577 vs 0.578 · Claude Sonnet 5 by 0.001
GPT-5.6 Terra vs Claude Opus 4.8 (Opus 4.8 grader)
0.577 vs 0.574 · GPT-5.6 Terra by 0.003
GPT-5.6 Terra vs Grok 4.7
0.577 vs 0.567 · GPT-5.6 Terra by 0.010
GPT-5.6 Terra vs Claude Opus 4.8
0.577 vs 0.558 · GPT-5.6 Terra by 0.019
GPT-5.6 Terra vs GPT-5.6 Luna
0.577 vs 0.557 · GPT-5.6 Terra by 0.020
GPT-5.6 Terra vs Muse Spark
0.577 vs 0.541 · GPT-5.6 Terra by 0.036
GPT-5.6 Terra vs GPT-5.6 Sol (August)
0.577 vs 0.540 · GPT-5.6 Terra by 0.037
GPT-5.6 Terra vs Claude Opus 4.7
0.577 vs 0.519 · GPT-5.6 Terra by 0.058
GPT-5.6 Terra vs GPT-5.5
0.577 vs 0.518 · GPT-5.6 Terra by 0.059
GPT-5.6 Terra vs Grok 4.6
0.577 vs 0.485 · GPT-5.6 Terra by 0.092
GPT-5.6 Terra vs GPT-5.4
0.577 vs 0.481 · GPT-5.6 Terra by 0.096
GPT-5.6 Terra vs GPT-5
0.577 vs 0.462 · GPT-5.6 Terra by 0.115
GPT-5.6 Terra vs GPT-5.2
0.577 vs 0.459 · GPT-5.6 Terra by 0.118
GPT-5.6 Terra vs Claude Sonnet 4.6
0.577 vs 0.442 · GPT-5.6 Terra by 0.135
GPT-5.6 Terra vs GPT-5.6 Luna (August)
0.577 vs 0.441 · GPT-5.6 Terra by 0.136
GPT-5.6 Terra vs GPT-5.1
0.577 vs 0.396 · GPT-5.6 Terra by 0.181
GPT-5.6 Terra vs GPT-5.5 Instant
0.577 vs 0.384 · GPT-5.6 Terra by 0.193
GPT-5.6 Terra vs MAI-Thinking-1
0.577 vs 0.350 · GPT-5.6 Terra by 0.227

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