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SOLVENCY

Head to head

GPT-5 vs o3-pro

GPT-5: legacyo3-pro: legacyheavy tier

Verdict · modelled basis

GPT-5 costs 11x less per solved task.

On output token price alone, GPT-5 looks 8.0x cheaper (16x on input). The ranking holds, but the margin changes.

Source: Aider polyglot benchmark · verified 2026-08-21 · prices from each provider's pricing page

Input $/M tokens

lower is better

  • GPT-5$1.25
  • o3-pro$20

Output $/M tokens

lower is better

  • GPT-5$10
  • o3-pro$80

Cost per solved task

modelled basis · lower is better

  • GPT-5$1.66
  • o3-pro$19.08
GPT-5o3-pro
Input $/Mtok$1.25$20
Output $/Mtok$10$80
Cached input $/Mtok$0.125missing
Pass rate88%85%
Pass rate sourceAiderAider
Cost basismodelledmodelled
Cost per solved task$1.66$19.08

verified 2026-08-21 · heavy task tier; measured rows ignore the tier· Methodology· GPT-5· o3-pro