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SOLVENCY

Head to head

GPT-5 vs Gemini 2.5 Pro

GPT-5: legacyGemini 2.5 Pro: legacyheavy tier

Verdict · modelled basis

GPT-5 costs 1.1x less per solved task.

On output token price alone, Gemini 2.5 Pro looks 1.0x cheaper (1.0x on input). The ranking reverses once you divide by pass rate — the cheaper tokens do not win the task.

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
  • Gemini 2.5 Pro$1.25

Output $/M tokens

lower is better

  • GPT-5$10
  • Gemini 2.5 Pro$10

Cost per solved task

modelled basis · lower is better

  • GPT-5$1.66
  • Gemini 2.5 Pro$1.76
GPT-5Gemini 2.5 Pro
Input $/Mtok$1.25$1.25
Output $/Mtok$10$10
Cached input $/Mtok$0.125$0.125
Pass rate88%83%
Pass rate sourceAiderAider
Cost basismodelledmodelled
Cost per solved task$1.66$1.76

verified 2026-08-21 · heavy task tier; measured rows ignore the tier· Methodology· GPT-5· Gemini 2.5 Pro