Which is cheaper, GPT-5.5 Pro or GPT OSS 20B High?
As of August 20, 2026, GPT OSS 20B High is 100% cheaper on blended LLM API pricing. GPT OSS 20B High costs $0.10 per million input tokens and $0.50 per million output tokens ($0.60 blended 1M-in + 1M-out). GPT-5.5 Pro costs $60.00 / $480.00 per million tokens ($540.00 blended). Sources: https://developers.openai.com/api/docs/pricing and https://developers.openai.com/api/docs/pricing. The cheapest LLM for your app still depends on how many output tokens you generate.
How much does GPT-5.5 Pro vs GPT OSS 20B High cost per million tokens?
GPT-5.5 Pro OpenAI API pricing is $60.00 input and $480.00 output per million tokens via OpenAI. GPT OSS 20B High OpenAI API pricing is $0.10 input and $0.50 output per million tokens via OpenAI. Use those four numbers, not ChatGPT Plus or Claude Pro subscription prices, when you are comparing APIs.
Which is better for coding, GPT-5.5 Pro or GPT OSS 20B High?
Neither GPT-5.5 Pro nor GPT OSS 20B High has a published SWE-bench or LiveCodeBench score on this page yet. Use the comparison table for the evals that do exist.
What is the context window for GPT-5.5 Pro vs GPT OSS 20B High?
GPT-5.5 Pro supports a 1M token context window, while GPT OSS 20B High supports 131K tokens. GPT-5.5 Pro offers a larger context window. Filling a larger window bills more input tokens, so the cheaper-per-million model can still cost more on long documents.
Which model performs better on benchmarks, GPT-5.5 Pro or GPT OSS 20B High?
GPT-5.5 Pro leads on 1 of 1 shared benchmarks versus GPT OSS 20B High's 0 wins. Check the comparison table for GPQA Diamond, SWE-bench, MMLU, HLE, and the other evals we track. Token price and benchmark score together are the usual LLM comparison, not either number alone.
Is GPT-5.5 Pro or GPT OSS 20B High better for production use?
Both GPT-5.5 Pro and GPT OSS 20B High are production API models. For cost-sensitive production traffic, GPT OSS 20B High has better economics on the blended 1M-in + 1M-out scale. For maximum capability, weight the benchmark table for your domain. Many production stacks route cheap models for drafts and a frontier model for the hard turn, which is usually cheaper than sending everything to the expensive API.
Can I switch between GPT-5.5 Pro and GPT OSS 20B High in my app?
Yes. Call GPT-5.5 Pro through OpenAI and GPT OSS 20B High through OpenAI with separate API keys, or through a gateway that already wraps both. Keep prompts in tokens, not characters, when you estimate the invoice. AnotherWrapper templates can swap providers without rewriting auth and billing.
How accurate is this GPT-5.5 Pro vs GPT OSS 20B High pricing data?
List rates are the latest published OpenAI API pricing and OpenAI API pricing, quoted per million tokens. Official rate sheets: https://developers.openai.com/api/docs/pricing and https://developers.openai.com/api/docs/pricing. Prompt caching, batch APIs, and committed-use discounts can change the invoice. Benchmark scores are from official publications and independent evals, updated as new numbers land.
What is the output token limit for GPT-5.5 Pro and GPT OSS 20B High?
GPT-5.5 Pro supports up to 128K output tokens per request, while GPT OSS 20B High supports up to 131K output tokens. Output tokens are usually the expensive half of API pricing, so a higher max output cap is a capability, not a discount.
Which model has better throughput, GPT-5.5 Pro or GPT OSS 20B High?
GPT OSS 20B High has a measured throughput of approximately 100 tokens/second. Throughput data for GPT-5.5 Pro is not yet available. Throughput (tokens per second) and time-to-first-token are why two models with the same per-million-token price can still feel different in chat and agents.
How do I switch the models in this GPT-5.5 Pro vs GPT OSS 20B High comparison?
Use the model pickers at the top of this LLM comparison. Search any model in the index and the URL updates. Open GPT-5.5 Pro or GPT OSS 20B High from the sidebar for the single-model API pricing page, or go back to the LLM pricing table to sort by cheapest blended cost.
