Clinical Benchmarks
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GPT-5.5 Instant

Released 5 May 2026$5 input, $30 output per million tokens400K contextproprietaryAlso written as GPT-5.5 Instant (June Update)

1 result on 1 of 13 boards, latest measured May 2026. Compare with other models

Clinical Benchmarks Index15.7Rank 137 of 1491 of 10 boardsAverage × multiplier 38.4 × 0.408 = 15.7This site’s own calculation. Working How it is computed

Results

Each line sits on its own board's scale. Tall tick: the board leader.

Clinical reasoning and knowledge

  1. HealthBench Professional
    length-adjusted (40.7 unadjusted, 2,775 mean response chars); GPT-5.5 Instant system card Table 5, column GPT-5.5 INSTANT.
    0.384
    Rank 33 of 35Leader GPT-6 Astra (Anthropic run) 0.703
    Vendor-reported
    Measured May 2026

Index working

The Clinical Benchmarks Index is this site's own calculation: a weighted average of the board scores times a multiplier for the boards behind it. How it is computed

  • HealthBench Professional0.38438.4×0.743length-adjusted (40.7 unadjusted, 2,775 mean response chars); GPT-5.5 Instant system card Table 5, column GPT-5.5 INSTANT.
One board, so its score
38.4
Multiplier for 1 of 10 boards
× 0.408
Index
38.4 × 0.408 = 15.7

Score: the result on the board’s own 0 to 100 scale. Dot: this model; tick: the board’s leader. Weight: how much the board counts in the weighted average. Each result links to its quote and page; the line under it is the setting it was measured with.

Sources

The quote, page and document for each of the 1 result
  1. 33HealthBench Professional length-adjusted 0.384
    Printed as 38.4Vendor-reported, measured May 2026Configuration: length-adjusted (40.7 unadjusted, 2,775 mean response chars); GPT-5.5 Instant system card Table 5, column GPT-5.5 INSTANT.
    GPT-5.5 Instant System Card system card, OpenAI, 5 May 2026. Section 4.1 HealthBench, Table 5 (reported as length-adjusted score (unadjusted, mean response length in characters)), 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)
    Every result from this document

Other OpenAI models: GPT-4.1, GPT-4.1 mini, GPT-4o, GPT-5, GPT-5.1, GPT-5.2, GPT-5.3-Codex, GPT-5.4, GPT-5.4 mini, GPT-5.4 nano, GPT-5.5, GPT-5.6 Luna, GPT-5.6 Sol, GPT-5.6 Terra, GPT-5 mini, GPT-5 nano, GPT-6.1 Sol, GPT-6 Astra, GPT-6 Luna, GPT-6 Sol, GPT OSS 120B, GPT OSS 20B, o3, o4-mini