Gemini 1.5 Pro vs Gemini 2.5 Flash Preview
Compare Gemini 1.5 Pro and Gemini 2.5 Flash Preview, both from Google AI, context windows of 1.0M vs 1.0M, tested across 16 shared challenges. Updated June 2026.
Which is better, Gemini 1.5 Pro or Gemini 2.5 Flash Preview?
Gemini 1.5 Pro and Gemini 2.5 Flash Preview are both competitive models. Gemini 1.5 Pro costs $3.5/M input tokens vs $0.15/M for Gemini 2.5 Flash Preview. Context windows: 1000K vs 1049K tokens. Compare their real outputs side by side below.
Key Differences Between Gemini 1.5 Pro and Gemini 2.5 Flash Preview
Gemini 1.5 Pro is made by google while Gemini 2.5 Flash Preview is from google. Gemini 1.5 Pro has a 1000K token context window compared to Gemini 2.5 Flash Preview's 1049K. On pricing, Gemini 1.5 Pro costs $3.5/M input tokens vs $0.15/M for Gemini 2.5 Flash Preview.
Per 1M tokens
Gemini 2.5 Flash Preview is cheaper on both — 23× input, 18× output
No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.
Gemini 2.5 Flash Preview is 18x cheaper per token — worth considering if cost matters.
Style Comparison
Gemini 2.5 Flash Preview uses 2.7x more transitions
