Claude Opus 4.8 (Fast) vs Gemini 3.1 Flash Image Preview: API Cost Comparison
Compare the API pricing, context windows, features, and real-world cost projections for Claude Opus 4.8 (Fast) (Anthropic) and Gemini 3.1 Flash Image Preview (Google). Use the interactive calculator below to compute your exact monthly cost based on your token usage and request volume.
Prices verified Jun 26, 2026
Interactive Cost Calculator
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Showing costs for 2 models. Cheapest: Gemini 3.1 Flash Image Preview at $20.00/month.
| Alert | |||||||
|---|---|---|---|---|---|---|---|
BestGemini 3.1 Flash Image Preview | $20.00 | $0.002000 | $5.00 | $15.00 | 94.3% | Alerts coming soon | |
Claude Opus 4.8 (Fast) | Anthropic | $350.00 | $0.035000 | $100.00 | $250.00 | — | Alerts coming soon |
Monthly Cost Comparison
Price Comparison at a Glance
All prices are in USD per 1 million tokens ($/M tokens). Lower is cheaper.
| Pricing Type | Claude Opus 4.8 (Fast) | Gemini 3.1 Flash Image Preview | Cheaper |
|---|---|---|---|
| Input (standard) | $10.00/M | $0.50/M | Gemini 3.1 Flash Image Preview |
| Output | $50.00/M | $3.00/M | Gemini 3.1 Flash Image Preview |
Prices last verified: 2026-03-27 – 2026-06-26
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 | Claude Opus 4.8 (Fast)Monthly | Gemini 3.1 Flash Image PreviewMonthly | Claude Opus 4.8 (Fast)Per request | Gemini 3.1 Flash Image PreviewPer request |
|---|---|---|---|---|
| 1K requests/mo | $35.00 | $2.00 | $0.035000 | $0.002000 |
| 10K requests/mo | $350.00 | $20.00 | $0.035000 | $0.002000 |
| 100K requests/mo | $3,500.00 | $200.00 | $0.035000 | $0.002000 |
| 1M requests/mo | $35,000.00 | $2,000.00 | $0.035000 | $0.002000 |
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 Claude Opus 4.8 (Fast)
by Anthropic
- General chatbot
Input / 1M tokens
$10.00/M
Output / 1M tokens
$50.00/M
Context window
1,000,000
Tier
premium
When to Choose Gemini 3.1 Flash Image Preview
by Google
- General chatbot
Input / 1M tokens
$0.50/M
Output / 1M tokens
$3.00/M
Context window
65,536
Tier
budget
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 | Claude Opus 4.8 (Fast) | Gemini 3.1 Flash Image Preview |
|---|---|---|
| Context window | 1,000,000 tokens | 65,536 tokens |
| Max output tokens | 128,000 tokens | 65,536 tokens |
| Performance tier | Premium | Budget |
| Vision / image input | Yes | Yes |
| Function calling | Yes | Yes |
| JSON mode | Yes | Yes |
| Prompt caching | No | No |
| Batch API (50% discount) | No | No |
| Extended reasoning | Yes | No |
| Fine-tuning | No | No |
Frequently Asked Questions
Is Claude Opus 4.8 (Fast) cheaper than Gemini 3.1 Flash Image Preview?
At standard usage (1,000 input tokens, 500 output tokens, 100,000 requests/month), Gemini 3.1 Flash Image Preview costs $200.00/month versus $3,500.00/month for Claude Opus 4.8 (Fast) — a 94% 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, Claude Opus 4.8 (Fast) or Gemini 3.1 Flash Image Preview?
Claude Opus 4.8 (Fast) has a larger context window at 1,000,000 tokens, compared to 65,536 tokens for Gemini 3.1 Flash Image Preview. A larger context window is important for processing long documents, multi-turn conversations, or large codebases without truncation.
Do Claude Opus 4.8 (Fast) and Gemini 3.1 Flash Image Preview support the Batch API?
Neither Claude Opus 4.8 (Fast) nor Gemini 3.1 Flash Image Preview currently supports a batch API with discounted pricing. For batch-eligible alternatives, consider models from OpenAI, Anthropic, or Google that include batch API support.
Which model offers better prompt caching?
Neither Claude Opus 4.8 (Fast) nor Gemini 3.1 Flash Image Preview currently supports prompt caching. For prompt-caching capable alternatives, consider Claude models from Anthropic or GPT-4o from OpenAI.
What are the best use cases for Claude Opus 4.8 (Fast) vs Gemini 3.1 Flash Image Preview?
Both models are well-suited for General chatbot. Claude Opus 4.8 (Fast) is particularly strong for overlapping tasks. Gemini 3.1 Flash Image Preview 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 Claude Opus 4.8 (Fast) vs Gemini 3.1 Flash Image Preview?
At 1,000 input tokens and 500 output tokens per request — a typical conversational workload — Claude Opus 4.8 (Fast) costs $0.035000 per request and Gemini 3.1 Flash Image Preview costs $0.002000 per request. At 100,000 requests/month, that translates to $3,500.00 and $200.00 respectively. Use the interactive calculator to adjust these parameters for your actual workload.
Claude Opus 4.8 (Fast) vs Gemini 3.1 Flash Image Preview: Summary
When comparing Claude Opus 4.8 (Fast) and Gemini 3.1 Flash Image Preview for API cost, the right choice depends on your workload's token profile, required features, and tolerance for latency. Gemini 3.1 Flash Image Preview 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 $3,500.00/month for Claude Opus 4.8 (Fast).
Both models are priced in USD per million tokens, the standard unit across all major AI API providers. Claude Opus 4.8 (Fast) charges $10.00/M for input tokens and $50.00/M for output tokens. Gemini 3.1 Flash Image Preview charges $0.50/M input and $3.00/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.
Context window capacity differs between the two: Claude Opus 4.8 (Fast) supports up to 1,000,000 tokens in a single request, versus 65,536 tokens for Gemini 3.1 Flash Image Preview. 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 Claude Opus 4.8 (Fast) or Gemini 3.1 Flash Image Preview is recommended.