API cost decision in 10 seconds

GPT-5.6 Sol Pro vs Claude Opus 4.8 (Fast)

Pick GPT-5.6 Sol Pro when budget and context both matter.

Page updated:  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 4.8 (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

Same prices, different token mixes.

GPT-5.6 Sol Pro stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shapeToken mixBetter pickGPT-5.6 Sol ProClaude Opus 4.8 (Fast)
Input-heavy / RAG5M input + 500K outputGPT-5.6 Sol Pro$15$75
Balanced workload1M input + 1M outputGPT-5.6 Sol Pro$12$60
Output-heavy chatbot1M input + 5M outputGPT-5.6 Sol Pro$52$260
Cheaper input GPT-5.6 Sol Pro $2 vs $10 / 1M

GPT-5.6 Sol Pro is $8 cheaper per 1M input tokens (80% lower; 5x difference).

Cheaper output GPT-5.6 Sol Pro $10 vs $50 / 1M

GPT-5.6 Sol Pro is $40 cheaper per 1M output tokens (80% lower; 5x difference).

Larger context GPT-5.6 Sol Pro 1.05M vs 1M

GPT-5.6 Sol Pro has 50K more context (1.05x larger).

Sample workload GPT-5.6 Sol Pro $7 vs $35

GPT-5.6 Sol Pro is $28 cheaper on the standard workload (80% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
GPT-5.6 Sol Pro Calculating… Estimated API cost
Claude Opus 4.8 (Fast) Calculating… Estimated API cost
Cheaper for this workload Calculating… Difference: calculating…

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

Verdict

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 $7 for GPT-5.6 Sol Pro and $35 for Claude Opus 4.8 (Fast).

Best Fit

Choose GPT-5.6 Sol Pro when you care most about lower input-token price, lower output-token price, and larger context window.

Choose Claude Opus 4.8 (Fast) when its provider, model quality, latency, or availability is more important than the numeric price/context winner.

Decision Notes
  • On the standard 1M input plus 500K output workload, GPT-5.6 Sol Pro is estimated at $7 vs $35 for Claude Opus 4.8 (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).
Head-to-Head Specs
FeatureGPT-5.6 Sol Pro
(OpenAI)		Claude Opus 4.8 (Fast)
(Anthropic)
Input Price
prompt tokens per 1M		$2$10
Completion Price
per 1M tokens		$10$50
Sample Workload Cost
1M input + 500K output		$7$35
Context Window1.05M1M
Release Date

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productionGPT-5.6 Sol ProOn the standard 1M input plus 500K output workload, GPT-5.6 Sol Pro is estimated at $7 vs $35 for Claude Opus 4.8 (Fast), saving $28 (80% lower).
High-volume input processingGPT-5.6 Sol ProLower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbotsGPT-5.6 Sol ProLower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workGPT-5.6 Sol ProA larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps
  • gpt-oss-120b (free) can replace GPT-5.6 Sol Pro when lower sample workload cost matters most: $0.
  • gpt-oss-20b (free) can replace GPT-5.6 Sol Pro when lower sample workload cost matters most: $0.
  • gpt-oss-20b can replace GPT-5.6 Sol Pro when lower sample workload cost matters most: $0.1.
  • gpt-oss-120b can replace GPT-5.6 Sol Pro when lower sample workload cost matters most: $0.12.

Cheaper alternatives

Review low-cost models sorted by a standard 1M input plus 500K output workload.

Open cheapest models

Larger context alternatives

Find models with larger context windows for RAG, long documents, and codebase review.

Open largest context models

Provider catalogs

Compare models within provider hubs before choosing a final API vendor.

Open provider hubs

OpenAI catalog

Review all tracked OpenAI models before deciding whether this matchup is the right shortlist.

Open OpenAI models

Anthropic catalog

Check other Anthropic models with comparable pricing, context, or release timing.

Open Anthropic models
GPT-5.6 Sol Pro

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

Claude Opus 4.8 (Fast)

Fast-mode variant of [Opus 4.8](/anthropic/claude-opus-4.8) - identical capabilities with higher output speed at 2x pricing relative to regular Opus 4.8. Learn more in Anthropic's docs: https://platform.claude.com/docs/en/build-with-claude/fast-mode