Claude Opus 4.8 (Fast) vs Claude Sonnet 4: API Cost Comparison
Compare the API pricing, context windows, features, and real-world cost projections for Claude Opus 4.8 (Fast) (Anthropic) and Claude Sonnet 4 (Anthropic). 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: Claude Sonnet 4 at $105.00/month.
| Alert | |||||||
|---|---|---|---|---|---|---|---|
BestClaude Sonnet 4 | Anthropic | $105.00 | $0.010500 | $30.00 | $75.00 | 70.0% | 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) | Claude Sonnet 4 | Cheaper |
|---|---|---|---|
| Input (standard) | $10.00/M | $3.00/M | Claude Sonnet 4 |
| Output | $50.00/M | $15.00/M | Claude Sonnet 4 |
| Cached input | N/A | $0.30/M | — |
| Batch input | N/A | $1.50/M | — |
| Batch output | N/A | $7.50/M | — |
Prices last verified: 2026-03-24 – 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 | Claude Sonnet 4Monthly | Claude Opus 4.8 (Fast)Per request | Claude Sonnet 4Per request |
|---|---|---|---|---|
| 1K requests/mo | $35.00 | $10.50 | $0.035000 | $0.010500 |
| 10K requests/mo | $350.00 | $105.00 | $0.035000 | $0.010500 |
| 100K requests/mo | $3,500.00 | $1,050.00 | $0.035000 | $0.010500 |
| 1M requests/mo | $35,000.00 | $10,500.00 | $0.035000 | $0.010500 |
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 Claude Sonnet 4
by Anthropic
- Code generation
- Content & copywriting
- RAG / Semantic search
Input / 1M tokens
$3.00/M
Output / 1M tokens
$15.00/M
Context window
200,000
Tier
mid
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) | Claude Sonnet 4 |
|---|---|---|
| Context window | 1,000,000 tokens | 200,000 tokens |
| Max output tokens | 128,000 tokens | 64,000 tokens |
| Performance tier | Premium | Mid |
| Vision / image input | Yes | Yes |
| Function calling | Yes | Yes |
| JSON mode | Yes | Yes |
| Prompt caching | No | Yes |
| Batch API (50% discount) | No | Yes |
| Extended reasoning | Yes | Yes |
| Fine-tuning | No | No |
| Rate limit (req/min) | Not published | 4,000 |
Claude Sonnet 4 notes
Extended thinking mode available for complex reasoning tasks. Strong coding benchmark scores.
Frequently Asked Questions
Is Claude Opus 4.8 (Fast) cheaper than Claude Sonnet 4?
At standard usage (1,000 input tokens, 500 output tokens, 100,000 requests/month), Claude Sonnet 4 costs $1,050.00/month versus $3,500.00/month for Claude Opus 4.8 (Fast) — a 70% 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 Claude Sonnet 4?
Claude Opus 4.8 (Fast) has a larger context window at 1,000,000 tokens, compared to 200,000 tokens for Claude Sonnet 4. 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 Claude Sonnet 4 support the Batch API?
Claude Sonnet 4 supports the Batch API (50% discount for async processing), while Claude Opus 4.8 (Fast) does not. If your workload tolerates up to 24-hour latency, routing to Claude Sonnet 4 with batch pricing could significantly cut costs versus Claude Opus 4.8 (Fast)'s standard rate.
Which model offers better prompt caching?
Claude Sonnet 4 supports prompt caching at $0.30/M for cached input, while Claude Opus 4.8 (Fast) does not offer prompt caching. For RAG applications or chatbots with large, repeated context, Claude Sonnet 4's caching capability can substantially reduce effective costs.
What are the best use cases for Claude Opus 4.8 (Fast) vs Claude Sonnet 4?
Claude Opus 4.8 (Fast) is best suited for General chatbot, while Claude Sonnet 4 is optimized for Code generation, Content & copywriting, RAG / Semantic search. Choose based on which use case matches your primary workload — and validate with the cost calculator above to confirm the total monthly spend fits your budget.
What is the cost per request for Claude Opus 4.8 (Fast) vs Claude Sonnet 4?
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 Claude Sonnet 4 costs $0.010500 per request. At 100,000 requests/month, that translates to $3,500.00 and $1,050.00 respectively. Use the interactive calculator to adjust these parameters for your actual workload.
Claude Opus 4.8 (Fast) vs Claude Sonnet 4: Summary
When comparing Claude Opus 4.8 (Fast) and Claude Sonnet 4 for API cost, the right choice depends on your workload's token profile, required features, and tolerance for latency. Claude Sonnet 4 offers lower total cost at standard usage volumes (1,000 input + 500 output tokens per request at 100,000 requests/month) at $1,050.00/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. Claude Sonnet 4 charges $3.00/M input and $15.00/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 Claude Sonnet 4 but not Claude Opus 4.8 (Fast). 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: Claude Opus 4.8 (Fast) supports up to 1,000,000 tokens in a single request, versus 200,000 tokens for Claude Sonnet 4. 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 Claude Sonnet 4 is recommended.