Gemini 3 Flash vs GPT-5.5 Pro: API Cost Comparison
Compare the API pricing, context windows, features, and real-world cost projections for Gemini 3 Flash (Google) and GPT-5.5 Pro (OpenAI). Use the interactive calculator below to compute your exact monthly cost based on your token usage and request volume.
Prices verified Apr 30, 2026
Interactive Cost Calculator
Fills in typical token counts for a workload type
Tokens in each prompt sent to the model
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Showing costs for 2 models. Cheapest: Gemini 3 Flash at $20.00/month.
| Alert | |||||||
|---|---|---|---|---|---|---|---|
BestGemini 3 Flash | $20.00 | $0.002000 | $5.00 | $15.00 | 98.3% | Alerts coming soon | |
GPT-5.5 Pro | OpenAI | $1,200.00 | $0.120000 | $300.00 | $900.00 | — | Alerts coming soon |
Monthly Cost Comparison
Price Comparison at a Glance
All prices are in USD per 1 million tokens ($/M tokens). Lower is cheaper.
| Pricing Type | Gemini 3 Flash | GPT-5.5 Pro | Cheaper |
|---|---|---|---|
| Input (standard) | $0.50/M | $30.00/M | Gemini 3 Flash |
| Output | $3.00/M | $180.00/M | Gemini 3 Flash |
| Cached input | $0.05/M | N/A | — |
| Batch input | $0.25/M | N/A | — |
| Batch output | $1.50/M | N/A | — |
Prices last verified: 2026-03-08 – 2026-04-30
Cost Breakdown by Usage Volume
Estimated monthly costs at different request volumes, assuming 1,000 input tokens and 500 output tokens per request. Adjust in the calculator above for your specific use case.
| Volume | Gemini 3 FlashMonthly | GPT-5.5 ProMonthly | Gemini 3 FlashPer request | GPT-5.5 ProPer request |
|---|---|---|---|---|
| 1K requests/mo | $2.00 | $120.00 | $0.002000 | $0.120000 |
| 10K requests/mo | $20.00 | $1,200.00 | $0.002000 | $0.120000 |
| 100K requests/mo | $200.00 | $12,000.00 | $0.002000 | $0.120000 |
| 1M requests/mo | $2,000.00 | $120,000.00 | $0.002000 | $0.120000 |
Green values indicate the lower-cost option at each volume tier. Cost per request is calculated at 1,000 input + 500 output tokens using standard (non-batch, non-cached) pricing.
Price History
Input price per 1M tokensWhen to Choose Gemini 3 Flash
by Google
- General chatbot
- Customer support
- Code generation
Input / 1M tokens
$0.50/M
Output / 1M tokens
$3.00/M
Context window
1,048,576
Tier
mid
When to Choose GPT-5.5 Pro
by OpenAI
- General chatbot
Input / 1M tokens
$30.00/M
Output / 1M tokens
$180.00/M
Context window
1,050,000
Tier
premium
Key Differences Beyond Price
Cost is only one factor in choosing an AI model. Context window size, rate limits, supported features, and latency all affect whether a model fits your use case.
| Capability | Gemini 3 Flash | GPT-5.5 Pro |
|---|---|---|
| Context window | 1,048,576 tokens | 1,050,000 tokens |
| Max output tokens | 65,536 tokens | 128,000 tokens |
| Performance tier | Mid | Premium |
| Vision / image input | Yes | Yes |
| Function calling | Yes | Yes |
| JSON mode | Yes | Yes |
| Prompt caching | Yes | No |
| Batch API (50% discount) | Yes | No |
| Extended reasoning | Yes | Yes |
| Fine-tuning | No | No |
| Rate limit (req/min) | 4,000 | Not published |
Gemini 3 Flash notes
Preview model. Thinking tokens available.
Frequently Asked Questions
Is Gemini 3 Flash cheaper than GPT-5.5 Pro?
At standard usage (1,000 input tokens, 500 output tokens, 100,000 requests/month), Gemini 3 Flash costs $200.00/month versus $12,000.00/month for GPT-5.5 Pro — a 98% saving. Your actual savings will vary based on your token profile; output-heavy workloads amplify differences in output pricing.
Which model has a larger context window, Gemini 3 Flash or GPT-5.5 Pro?
GPT-5.5 Pro has a larger context window at 1,050,000 tokens, compared to 1,048,576 tokens for Gemini 3 Flash. A larger context window is important for processing long documents, multi-turn conversations, or large codebases without truncation.
Do Gemini 3 Flash and GPT-5.5 Pro support the Batch API?
Gemini 3 Flash supports the Batch API (50% discount for async processing), while GPT-5.5 Pro does not. If your workload tolerates up to 24-hour latency, routing to Gemini 3 Flash with batch pricing could significantly cut costs versus GPT-5.5 Pro's standard rate.
Which model offers better prompt caching?
Gemini 3 Flash supports prompt caching at $0.05/M for cached input, while GPT-5.5 Pro does not offer prompt caching. For RAG applications or chatbots with large, repeated context, Gemini 3 Flash's caching capability can substantially reduce effective costs.
What are the best use cases for Gemini 3 Flash vs GPT-5.5 Pro?
Both models are well-suited for General chatbot. Gemini 3 Flash is particularly strong for Customer support, Code generation. GPT-5.5 Pro is favored for similar workflows. At the same quality level, the lower-cost model is usually preferable; use this page's calculator to compare total monthly spend at your volume.
What is the cost per request for Gemini 3 Flash vs GPT-5.5 Pro?
At 1,000 input tokens and 500 output tokens per request — a typical conversational workload — Gemini 3 Flash costs $0.002000 per request and GPT-5.5 Pro costs $0.120000 per request. At 100,000 requests/month, that translates to $200.00 and $12,000.00 respectively. Use the interactive calculator to adjust these parameters for your actual workload.
Gemini 3 Flash vs GPT-5.5 Pro: Summary
When comparing Gemini 3 Flash and GPT-5.5 Pro for API cost, the right choice depends on your workload's token profile, required features, and tolerance for latency. Gemini 3 Flash offers lower total cost at standard usage volumes (1,000 input + 500 output tokens per request at 100,000 requests/month) at $200.00/month, compared to $12,000.00/month for GPT-5.5 Pro.
Both models are priced in USD per million tokens, the standard unit across all major AI API providers. Gemini 3 Flash charges $0.50/M for input tokens and $3.00/M for output tokens. GPT-5.5 Pro charges $30.00/M input and $180.00/M output. If your workload is output-heavy (more tokens generated than consumed as input), the model with the lower output price compounds cost savings significantly at scale.
Prompt caching is supported by Gemini 3 Flash but not GPT-5.5 Pro. For workloads with large, repeated system prompts or document context — such as RAG pipelines or multi-turn conversations with a fixed knowledge base — prompt caching can reduce effective input costs by 60–90%, which may change the cost ranking between these two models at your specific usage pattern.
Context window capacity differs between the two: GPT-5.5 Pro supports up to 1,050,000 tokens in a single request, versus 1,048,576 tokens for Gemini 3 Flash. A larger context window is essential for document summarization, large codebase analysis, and multi-document retrieval-augmented generation (RAG) applications.
Use the interactive calculator at the top of this page to enter your actual token usage and monthly request volume for a precise cost comparison tailored to your workload. Adjust for batch API discounts and prompt caching to find the most cost-effective option for your specific deployment.
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Relevant Use Cases
See cost recommendations for workloads where Gemini 3 Flash or GPT-5.5 Pro is recommended.