API cost decision in 10 seconds

🔥Claude Sonnet 4.6 vs gpt-oss-20b (free)

Pick gpt-oss-20b (free) for lower cost; pick Claude Sonnet 4.6 only if the larger context window matters more.

Page updated:  Data confirmed:  Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick gpt-oss-20b (free) for lower cost; pick Claude Sonnet 4.6 only if the larger context window matters more.

On the standard 1M input plus 500K output workload, gpt-oss-20b (free) is estimated at $0 vs $10.5 for Claude Sonnet 4.6, saving $10.5 (100% lower).

Cost-first pickgpt-oss-20b (free)
Context-first pickClaude Sonnet 4.6
Sample savings$10.5100%
10x traffic gap$105

Claude Sonnet 4.6 has more context, but gpt-oss-20b (free) saves $10.5 on the standard workload. At 10x that traffic, the same price gap is about $105. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

gpt-oss-20b (free) stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shapeToken mixBetter pickClaude Sonnet 4.6gpt-oss-20b (free)
Input-heavy / RAG5M input + 500K outputgpt-oss-20b (free)$22.5$0
Balanced workload1M input + 1M outputgpt-oss-20b (free)$18$0
Output-heavy chatbot1M input + 5M outputgpt-oss-20b (free)$78$0
Cheaper input gpt-oss-20b (free) $3 vs $0 / 1M

gpt-oss-20b (free) is free for input tokens while Claude Sonnet 4.6 costs $3 per 1M tokens.

Cheaper output gpt-oss-20b (free) $15 vs $0 / 1M

gpt-oss-20b (free) is free for output tokens while Claude Sonnet 4.6 costs $15 per 1M tokens.

Larger context Claude Sonnet 4.6 1M vs 131.07K

Claude Sonnet 4.6 has 868.93K more context (7.63x larger).

Sample workload gpt-oss-20b (free) $10.5 vs $0

gpt-oss-20b (free) is free for the standard workload while the other model is estimated at $10.5.

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
Claude Sonnet 4.6 Calculating… Estimated API cost
gpt-oss-20b (free) 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-oss-20b (free) has the lower input price; gpt-oss-20b (free) has the lower output price; Claude Sonnet 4.6 offers the larger context window. For the 1M input plus 500K output sample, gpt-oss-20b (free) is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $10.5 for Claude Sonnet 4.6 and $0 for gpt-oss-20b (free).

Best Fit

Choose Claude Sonnet 4.6 when you care most about larger context window.

Choose gpt-oss-20b (free) when you care most about lower input-token price, and lower output-token price.

Decision Notes
  • On the standard 1M input plus 500K output workload, gpt-oss-20b (free) is estimated at $0 vs $10.5 for Claude Sonnet 4.6, saving $10.5 (100% lower).
  • gpt-oss-20b (free) is free for the standard workload while the other model is estimated at $10.5.
  • gpt-oss-20b (free) is free for input tokens while Claude Sonnet 4.6 costs $3 per 1M tokens.
  • gpt-oss-20b (free) is free for output tokens while Claude Sonnet 4.6 costs $15 per 1M tokens.
  • Claude Sonnet 4.6 has 868.93K more context (7.63x larger).
Head-to-Head Specs
Feature🔥Claude Sonnet 4.6
(Anthropic)		gpt-oss-20b (free)
(OpenAI)
Input Price
prompt tokens per 1M		$3$0
Completion Price
per 1M tokens		$15$0
Sample Workload Cost
1M input + 500K output		$10.5$0
Context Window1M131.07K
Release Date
Popularity#4#72

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productiongpt-oss-20b (free)On the standard 1M input plus 500K output workload, gpt-oss-20b (free) is estimated at $0 vs $10.5 for Claude Sonnet 4.6, saving $10.5 (100% lower).
High-volume input processinggpt-oss-20b (free)Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbotsgpt-oss-20b (free)Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workClaude Sonnet 4.6A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps
  • Claude 3 Haiku can replace Claude Sonnet 4.6 when lower sample workload cost matters most: $0.88.
  • Claude 3.5 Haiku can replace Claude Sonnet 4.6 when lower sample workload cost matters most: $2.8.
  • Anthropic Claude Haiku Latest can replace Claude Sonnet 4.6 when lower sample workload cost matters most: $3.5.
  • Claude Haiku 4.5 can replace Claude Sonnet 4.6 when lower sample workload cost matters most: $3.5.
Larger context near this budget
  • Llama 4 Scout offers 10M context with $0.23 sample workload cost.
  • Grok 4.20 offers 2M context with $2.5 sample workload cost.
  • Grok 4.20 Multi-Agent offers 2M context with $5 sample workload cost.
  • GPT-5.4 offers 1.05M context with $10 sample workload cost.

Cheaper alternatives

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

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Larger context alternatives

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

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Provider catalogs

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Anthropic catalog

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

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OpenAI catalog

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

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Claude Sonnet 4.6

Sonnet 4.6 is Anthropic's most capable Sonnet-class model yet, with frontier performance across coding, agents, and professional work. It excels at iterative development, complex codebase navigation, end-to-end project management with...

gpt-oss-20b (free)

gpt-oss-20b is an open-weight 21B parameter model released by OpenAI under the Apache 2.0 license. It uses a Mixture-of-Experts (MoE) architecture with 3.6B active parameters per forward pass, optimized for...