GPT-5.6 Sol Pro is $8 cheaper per 1M input tokens (80% lower; 5x difference).
API cost decision in 10 seconds
Claude Opus 5 (Fast) vs GPT-5.6 Sol Pro
Pick GPT-5.6 Sol Pro when budget and context both matter.
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Data confirmed:
Prices normalized to USD per 1M tokens
Sample workload: 1M input + 500K output
Budget verdict
Pick GPT-5.6 Sol Pro when budget and context both matter.
On the standard 1M input plus 500K output workload, GPT-5.6 Sol Pro is estimated at $7 vs $35 for Claude Opus 5 (Fast), saving $28 (80% lower).
Cost-first pickGPT-5.6 Sol Pro
Context-first pickGPT-5.6 Sol Pro
Sample savings$2880%
10x traffic gap$280
GPT-5.6 Sol Pro is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $280. Use the calculator below to replace the sample workload with your own token volume.
Cost sensitivity
Workload Sensitivity
GPT-5.6 Sol Pro stays cheaper across input-heavy, balanced, and output-heavy sample workloads.
| Workload shape | Token mix | Better pick | Claude Opus 5 (Fast) | GPT-5.6 Sol Pro |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | GPT-5.6 Sol Pro | $75 | $15 |
| Balanced workload | 1M input + 1M output | GPT-5.6 Sol Pro | $60 | $12 |
| Output-heavy chatbot | 1M input + 5M output | GPT-5.6 Sol Pro | $260 | $52 |
GPT-5.6 Sol Pro is $40 cheaper per 1M output tokens (80% lower; 5x difference).
GPT-5.6 Sol Pro has 50K more context (1.05x larger).
GPT-5.6 Sol Pro is $28 cheaper on the standard workload (80% lower).
Estimate your workload cost
Your Workload Cost
This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.
Quick Decision
GPT-5.6 Sol Pro has the lower input price; GPT-5.6 Sol Pro has the lower output price; GPT-5.6 Sol Pro offers the larger context window. For the 1M input plus 500K output sample, GPT-5.6 Sol Pro is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $35 for Claude Opus 5 (Fast) and $7 for GPT-5.6 Sol Pro.
Choose Claude Opus 5 (Fast) when its provider, model quality, latency, or availability is more important than the numeric price/context winner.
Choose GPT-5.6 Sol Pro when you care most about lower input-token price, lower output-token price, and larger context window.
- On the standard 1M input plus 500K output workload, GPT-5.6 Sol Pro is estimated at $7 vs $35 for Claude Opus 5 (Fast), saving $28 (80% lower).
- GPT-5.6 Sol Pro is $28 cheaper on the standard workload (80% lower).
- GPT-5.6 Sol Pro is $8 cheaper per 1M input tokens (80% lower; 5x difference).
- GPT-5.6 Sol Pro is $40 cheaper per 1M output tokens (80% lower; 5x difference).
- GPT-5.6 Sol Pro has 50K more context (1.05x larger).
| Feature | Claude Opus 5 (Fast) (Anthropic) | GPT-5.6 Sol Pro (OpenAI) |
|---|---|---|
| Input Price prompt tokens per 1M | $10 | $2 |
| Completion Price per 1M tokens | $50 | $10 |
| Sample Workload Cost 1M input + 500K output | $35 | $7 |
| Context Window | 1M | 1.05M |
| Release Date |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | GPT-5.6 Sol Pro | On the standard 1M input plus 500K output workload, GPT-5.6 Sol Pro is estimated at $7 vs $35 for Claude Opus 5 (Fast), saving $28 (80% lower). |
| High-volume input processing | GPT-5.6 Sol Pro | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | GPT-5.6 Sol Pro | Lower output-token price matters most when assistants generate many completion tokens. |
| RAG or long-document work | GPT-5.6 Sol Pro | A larger context window leaves more room for retrieved passages, conversation history, or source files. |
Related Alternatives
- Claude 3 Haiku can replace Claude Opus 5 (Fast) when lower sample workload cost matters most: $0.88.
- Claude Haiku 4.5 (batch) can replace Claude Opus 5 (Fast) when lower sample workload cost matters most: $1.75.
- Claude 3.5 Haiku can replace Claude Opus 5 (Fast) when lower sample workload cost matters most: $2.8.
- Claude Sonnet 5 (batch) can replace Claude Opus 5 (Fast) when lower sample workload cost matters most: $3.5.
- Grok 4.20 Multi-Agent offers 2M context with $2.5 sample workload cost.
- Grok 4.20 offers 2M context with $2.5 sample workload cost.
- DeepSeek V4 Flash 0731 offers 1.31M context with $0.17 sample workload cost.
- DeepSeek V4 Flash Latest offers 1.31M context with $0.11 sample workload cost.
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Cheaper alternatives
Review low-cost models sorted by a standard 1M input plus 500K output workload.
Open cheapest modelsLarger context alternatives
Find models with larger context windows for RAG, long documents, and codebase review.
Open largest context modelsProvider catalogs
Compare models within provider hubs before choosing a final API vendor.
Open provider hubsAnthropic catalog
Review all tracked Anthropic models before deciding whether this matchup is the right shortlist.
Open Anthropic modelsOpenAI catalog
Check other OpenAI models with comparable pricing, context, or release timing.
Open OpenAI modelsFast-mode variant of [Opus 5](/anthropic/claude-opus-5) - identical capabilities with higher output speed at 2x pricing relative to regular Opus 5. Learn more in Anthropic's docs: https://platform.claude.com/docs/en/build-with-claude/fast-mode
GPT-5.6 Sol Pro is the same underlying model as [GPT-5.6 Sol](https://openrouter.ai/openai/gpt-5.6-sol), served with `reasoning.mode` set to `pro` for higher-quality responses on complex tasks. Learn more in OpenAI's docs: https://developers.openai.com/api/docs/guides/reasoning#reasoning-mode