GPT-5.5 Instant on HealthBench Professional

rank 30 of 31 · updated September 30, 2026

GPT-5.5 Instant scores 0.384 on HealthBench Professional, rank 30 of 31 models on the board. The fast variant that became ChatGPT's default model in May 2026. 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	30 of 31
score	0.384
lab	OpenAI
context window	400K tokens
API price per 1M tokens	$5.00 in / $30.00 out
license	proprietary
source	GPT-5.5 Instant System Card (system card)
released	2026-05-05

Position in the field

The gap to the leader, GPT-6 Astra (Anthropic run) at 0.703, is 0.319. Directly above sits GPT-5.1 at 0.396. Directly below sits MAI-Thinking-1 at 0.350. 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-5.5 Instant System Card (system card, OpenAI, 2026-05-05). Vendor-reported. Confidence: verified. Configuration: length-adjusted (40.7 unadjusted, 2,775 mean response chars); GPT-5.5 Instant system card Table 5, column GPT-5.5 INSTANT..

HealthBench Professional 37.6 (40.4, 2,973) 35.7 (38.3, 2,872) 32.9 (33.8, 2,285) 38.4 (40.7, 2,775)

Section 4.1 HealthBench, Table 5 (reported as length-adjusted score (unadjusted, mean response length in characters)), column GPT-5.5 INSTANT · 1 corroborating document · full entry on the sources page

What does GPT-5.5 Instant score on HealthBench Professional?

GPT-5.5 Instant scores 0.384 on HealthBench Professional, which places it at rank 30 of 31 models on the board as of September 30, 2026. The number was read from GPT-5.5 Instant System Card, listed on the sources page.

How much does GPT-5.5 Instant cost to run?

GPT-5.5 Instant is priced at $5.00 per million input tokens and $30.00 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-5.5 Instant vs GPT-6 Astra (Anthropic run)
0.384 vs 0.703 · GPT-6 Astra (Anthropic run) by 0.319
GPT-5.5 Instant vs Claude Sonnet 5.5
0.384 vs 0.692 · Claude Sonnet 5.5 by 0.308
GPT-5.5 Instant vs Claude Fable 5
0.384 vs 0.660 · Claude Fable 5 by 0.276
GPT-5.5 Instant vs Claude Opus 5.5
0.384 vs 0.656 · Claude Opus 5.5 by 0.272
GPT-5.5 Instant vs GPT-6 Astra
0.384 vs 0.647 · GPT-6 Astra by 0.263
GPT-5.5 Instant vs Claude Fable 5 (September card)
0.384 vs 0.633 · Claude Fable 5 (September card) by 0.249
GPT-5.5 Instant vs Claude Fable 5.1
0.384 vs 0.621 · Claude Fable 5.1 by 0.237
GPT-5.5 Instant vs GPT-6 Luna
0.384 vs 0.608 · GPT-6 Luna by 0.224
GPT-5.5 Instant vs GPT-6 Sol
0.384 vs 0.608 · GPT-6 Sol by 0.224
GPT-5.5 Instant vs GPT-5.6 Sol
0.384 vs 0.605 · GPT-5.6 Sol by 0.221
GPT-5.5 Instant vs Claude Opus 5
0.384 vs 0.598 · Claude Opus 5 by 0.214
GPT-5.5 Instant vs Muse Spark 1.1
0.384 vs 0.593 · Muse Spark 1.1 by 0.209
GPT-5.5 Instant vs Claude Sonnet 5
0.384 vs 0.578 · Claude Sonnet 5 by 0.194
GPT-5.5 Instant vs GPT-5.6 Terra
0.384 vs 0.577 · GPT-5.6 Terra by 0.193
GPT-5.5 Instant vs Claude Opus 4.8 (Opus 4.8 grader)
0.384 vs 0.574 · Claude Opus 4.8 (Opus 4.8 grader) by 0.190
GPT-5.5 Instant vs Grok 4.7
0.384 vs 0.567 · Grok 4.7 by 0.183
GPT-5.5 Instant vs Claude Opus 4.8
0.384 vs 0.558 · Claude Opus 4.8 by 0.174
GPT-5.5 Instant vs GPT-5.6 Luna
0.384 vs 0.557 · GPT-5.6 Luna by 0.173
GPT-5.5 Instant vs Muse Spark
0.384 vs 0.541 · Muse Spark by 0.157
GPT-5.5 Instant vs GPT-5.6 Sol (August)
0.384 vs 0.540 · GPT-5.6 Sol (August) by 0.156
GPT-5.5 Instant vs Claude Opus 4.7
0.384 vs 0.519 · Claude Opus 4.7 by 0.135
GPT-5.5 Instant vs GPT-5.5
0.384 vs 0.518 · GPT-5.5 by 0.134
GPT-5.5 Instant vs Grok 4.6
0.384 vs 0.485 · Grok 4.6 by 0.101
GPT-5.5 Instant vs GPT-5.4
0.384 vs 0.481 · GPT-5.4 by 0.097
GPT-5.5 Instant vs GPT-5
0.384 vs 0.462 · GPT-5 by 0.078
GPT-5.5 Instant vs GPT-5.2
0.384 vs 0.459 · GPT-5.2 by 0.075
GPT-5.5 Instant vs Claude Sonnet 4.6
0.384 vs 0.442 · Claude Sonnet 4.6 by 0.058
GPT-5.5 Instant vs GPT-5.6 Luna (August)
0.384 vs 0.441 · GPT-5.6 Luna (August) by 0.057
GPT-5.5 Instant vs GPT-5.1
0.384 vs 0.396 · GPT-5.1 by 0.012
GPT-5.5 Instant vs MAI-Thinking-1
0.384 vs 0.350 · GPT-5.5 Instant by 0.034

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