Gemini 3.5 Flash vs GPT-5.4: fast utility vs frontier flagship pricing
Gemini is 40% cheaper on the listed standard input, output, and cache-read rows. Choose based on required inputs, task results, and prompt size rather than the old 5x price claim.
Utility cost versus premium flagship performance.
Choosing between a lightweight fast model and a fully capable intelligence model requires analyzing your API bill. Here is how Gemini 3.5 Flash and GPT-5.4 stack up.
By TechCompare · Updated
Cost Comparison
Based on 100,000 input tokens (50% cached), 5,000 output tokens, and 100 requests.Provider USD token rates. Cache storage, cache writes, and other service fees aren't included.
Side-by-side specs
| Spec | Gemini 3.5 Flash | GPT-5.4 |
|---|---|---|
| Input cost per 1M tokens, GPT prompts up to 272K | $1.50 (better on this spec) | $2.50 |
| Output cost per 1M tokens, GPT prompts up to 272K | $9.00 (better on this spec) | $15.00 |
| Cache reads per 1M tokens, GPT prompts up to 272K | $0.15 (better on this spec) | $0.25 |
| Batch discount | 50% | 50% |
How they differ
Gemini 3.5 Flash charges $1.50/M input, $9/M output, and $0.15/M cache reads. GPT-5.4 charges $2.50/M input, $15/M output, and $0.25/M cache reads for prompts up to 272K input tokens. Above 272K, GPT-5.4 charges double input and 1.5 times output for the full session. Both offer 50% batch token discounts. Google cache storage is additional. These official USD rates were checked on October 7, 2026.
Verdict
At the listed short-context tier, Gemini costs $1.50/$9/$0.15 per million input/output/cache-read tokens versus GPT-5.4 at $2.50/$15/$0.25. Gemini is 40% cheaper in each category, and matching 50% batch discounts preserve that ratio. For 100K input, half cached, and 5K output, Gemini costs $0.1275 and GPT-5.4 costs $0.2125 before extra services. Above 272K input tokens, GPT-5.4 uses its higher full-session pricing. Google cache storage is billed separately.
Which should you pick?
Choose Gemini 3.5 Flash
High-volume classification, basic search filtering, and low-latency runs.
Choose GPT-5.4
Advanced logical reasoning, data synthesis, and deep research tasks.