Google: Gemini 2.5 Flash vs OpenAI: GPT-5.1
Google: Gemini 2.5 Flash is cheaper than OpenAI: GPT-5.1 by about 75% on a blended (75% input / 25% output) basis. Google: Gemini 2.5 Flash charges $0.300000 / $2.500000 per 1M input/output tokens; OpenAI: GPT-5.1 charges $1.250000 / $10.000000.
| Field | Google: Gemini 2.5 Flash | OpenAI: GPT-5.1 |
|---|---|---|
| Input $/Mtok | $0.300000 | $1.250000 |
| Output $/Mtok | $2.500000 | $10.000000 |
| Cache read $/Mtok | $0.030000 | $0.125000 |
| Cache write $/Mtok | – | – |
| Input $/Mchar | n/a | 0.352142 |
| Output $/Mchar | n/a | 2.817139 |
| Context window | 1048576 | 400000 |
| Tokenizer | gemini | o200k |
Price history
Same workload, monthly cost
Illustrative monthly cost at 10M tokens/month, split per workload preset. Not a substitute for the calculator, which uses your own volume, cache and batch assumptions.
| Workload | Google: Gemini 2.5 Flash | OpenAI: GPT-5.1 |
|---|---|---|
| Coding agent | $4.10 | $16.88 |
| RAG chat | $6.30 | $25.63 |
| Summarisation (batch) | $5.20 | $21.25 |
| Classification | $3.44 | $14.25 |
| Chat assistant | $11.80 | $47.50 |
| Content generation | $20.60 | $82.50 |
Cite this page
Google: Gemini 2.5 Flash vs OpenAI: GPT-5.1: $0.300000/$2.500000 vs $1.250000/$10.000000 per 1M tokens, as of 2026-10-04 (Token Barometer, https://tokenbarometer.com/compare/google_gemini-2.5-flash-vs-openai_gpt-5.1).
Google: Gemini 2.5 Flash page | OpenAI: GPT-5.1 page | Open in calculator