Comparison · prices as of 2026-07-04 · re-verified 2026-08-18
Claude Sonnet 4.5 vs Gemini 2.5 Flash
On price alone, Gemini 2.5 Flash (Google) runs about 86% cheaper than Claude Sonnet 4.5 for a typical chat workload (2K input + 500 output tokens, 1,000 requests/day). Whether that's the right trade depends on the capability gap — the breakdown below shows where each one wins.
Price per million tokens
| Spec | Claude Sonnet 4.5 | Gemini 2.5 Flash |
|---|---|---|
| Input / MTok | $3 | $0.30 |
| Output / MTok | $15 | $2.50 |
| Context window | 200K | 1M |
| Max output | 64K | 66K |
| Class | workhorse | workhorse |
Estimated monthly cost by workload
Same models, three realistic usage levels. The gap between them scales with volume, so the right pick can change as you grow.
| Workload | Claude Sonnet 4.5 | Gemini 2.5 Flash | Cheaper |
|---|---|---|---|
| Light — chatbot 0.5K in / 0.2K out · 200 req/day | $27.00 | $3.90 | Gemini 2.5 Flash |
| Typical — assistant 2K in / 0.5K out · 1K req/day | $405 | $55.50 | Gemini 2.5 Flash |
| Heavy — RAG / agent 8K in / 2K out · 5K req/day | $8,100 | $1,110 | Gemini 2.5 Flash |
Which should you pick?
- Cheapest overall: Gemini 2.5 Flash — about 86% less per month on a typical assistant workload.
- Gemini 2.5 Flash is cheaper on both input and output, so it stays cheaper whether your workload is prompt-heavy or generation-heavy.
- Largest context window: Gemini 2.5 Flash at 1M tokens vs 200K — the one to pick if you feed in whole documents or codebases.
Frequently asked questions
Is Claude Sonnet 4.5 or Gemini 2.5 Flash cheaper?
Gemini 2.5 Flash is cheaper — roughly 86% less per month on a typical assistant workload (2K input + 500 output tokens, 1,000 requests/day).
What do Claude Sonnet 4.5 and Gemini 2.5 Flash cost per million tokens?
Claude Sonnet 4.5 is $3 per million input tokens and $15 per million output. Gemini 2.5 Flash is $0.30 input and $2.50 output. Prices are first-party API list rates as of 2026-07-04.
Which has the larger context window, Claude Sonnet 4.5 or Gemini 2.5 Flash?
Gemini 2.5 Flash does, at 1M tokens versus 200K for Claude Sonnet 4.5.
When should I choose Claude Sonnet 4.5 over Gemini 2.5 Flash?
Both are workhorse-class models, so choose Claude Sonnet 4.5 when it measurably wins on your own evals or you prefer its provider (Anthropic); otherwise Gemini 2.5 Flash does the same job for less.
Related comparisons
Sources: Anthropic pricing · Google pricing. Run your own numbers in the cost calculator.