Which is cheaper, Gemini 3.1 Pro or GPT-5.5?

Gemini 3.1 Pro. On a task of 1,500 input and 500 output tokens across 3 calls, Gemini 3.1 Pro costs $0.02700 per task against $0.06750 for GPT-5.5, which makes it 2.50x cheaper (a 60% saving).

How much do Gemini 3.1 Pro and GPT-5.5 charge per million tokens?

Gemini 3.1 Pro: $2 per million input tokens and $12 per million output tokens. GPT-5.5: $5 input and $30 output. These are published list rates as of August 2026, excluding cached, batch and long-context tiers.

What does a million tasks cost on Gemini 3.1 Pro vs GPT-5.5?

At the same fixed profile, one million tasks cost $27,000 on Gemini 3.1 Pro and $67,500 on GPT-5.5. The gap comes entirely from list-price differences, not from any difference in the work done.

Model price comparisons · August 2026

Gemini 3.1 Pro vs GPT-5.5: API pricing compared

Same task, same tokens, two invoices. Every figure on this page is computed from our open pricing dataset, not copied from a blog post.

Gemini 3.1 Pro is 2.50x cheaper than GPT-5.5 on a realistic task profile of 1,500 input and 500 output tokens per call, 3 calls per task: $0.02700 against $0.06750 per task, a 60% saving on identical work. Run a million tasks a month and that is the difference between $27,000 and $67,500.

Model	Input $/1M tok	Output $/1M tok	Output multiple	$/task	$/1M tasks
Gemini 3.1 ProGoogle · frontier	$2	$12	6x	$0.02700	$27,000
GPT-5.5OpenAI · frontier	$5	$30	6x	$0.06750	$67,500

Monthly bill at three volumes

Tasks / month	Gemini 3.1 Pro	GPT-5.5	Gap
10,000	$270	$675	$405
100,000	$2,700	$6,750	$4,050
1,000,000	$27,000	$67,500	$40,500

Where the money goes on each

Gemini 3.1 Pro prices output at 6x its input rate, so on this profile output is 67% of its task cost. GPT-5.5 prices output at 6x input, putting output at 67% of cost. The model with the higher output multiple rewards capping response length more; the one with the higher input share rewards prompt caching and context trimming more. Cost tells you nothing about quality: run both on twenty of your real cases before deciding, and treat the cheaper model as the default until it demonstrably fails.

Break-even against a dedicated GPU

Against a $2/hour dedicated instance ($1,460/month fixed), self-hosting overtakes Gemini 3.1 Pro at 54,074 tasks per month and overtakes GPT-5.5 at 21,630 tasks per month. The full method is in the self-hosting break-even guide.

Pricing the self-hosted side? Compare on-demand GPU rates:

Compare GPU cloud pricing →

Plug your own token counts into the $/task calculator, or read the full ten-model pricing comparison.

Compare against other models

Frequently asked

Which is cheaper, Gemini 3.1 Pro or GPT-5.5?: Gemini 3.1 Pro. On a task of 1,500 input and 500 output tokens across 3 calls, Gemini 3.1 Pro costs $0.02700 per task against $0.06750 for GPT-5.5, which makes it 2.50x cheaper (a 60% saving).
How much do Gemini 3.1 Pro and GPT-5.5 charge per million tokens?: Gemini 3.1 Pro: $2 per million input tokens and $12 per million output tokens. GPT-5.5: $5 input and $30 output. These are published list rates as of August 2026, excluding cached, batch and long-context tiers.
What does a million tasks cost on Gemini 3.1 Pro vs GPT-5.5?: At the same fixed profile, one million tasks cost $27,000 on Gemini 3.1 Pro and $67,500 on GPT-5.5. The gap comes entirely from list-price differences, not from any difference in the work done.