Which is cheaper, GPT-5.4 mini or Phi-3.5-mini-instruct?
As of August 25, 2026, Phi-3.5-mini-instruct is 96% cheaper on blended LLM API pricing. Phi-3.5-mini-instruct costs $0.10 per million input tokens and $0.10 per million output tokens ($0.20 blended 1M-in + 1M-out). GPT-5.4 mini costs $0.75 / $4.50 per million tokens ($5.25 blended). Sources: https://developers.openai.com/api/docs/pricing and https://azure.microsoft.com/en-us/pricing/details/cognitive-services/openai-service/. The cheapest LLM for your app still depends on how many output tokens you generate.
How much does GPT-5.4 mini vs Phi-3.5-mini-instruct cost per million tokens?
GPT-5.4 mini OpenAI API pricing is $0.75 input and $4.50 output per million tokens via OpenAI. Phi-3.5-mini-instruct Microsoft API pricing is $0.10 input and $0.10 output per million tokens via Microsoft. Use those four numbers, not ChatGPT Plus or Claude Pro subscription prices, when you are comparing APIs.
Which is better for coding, GPT-5.4 mini or Phi-3.5-mini-instruct?
GPT-5.4 mini has a published SWE-bench Verified score of 73%. Phi-3.5-mini-instruct does not have that eval on this page yet.
What is the context window for GPT-5.4 mini vs Phi-3.5-mini-instruct?
GPT-5.4 mini supports a 400K token context window, while Phi-3.5-mini-instruct supports 128K tokens. GPT-5.4 mini 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-5.4 mini or Phi-3.5-mini-instruct?
GPT-5.4 mini leads on 2 of 2 shared benchmarks versus Phi-3.5-mini-instruct'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-5.4 mini or Phi-3.5-mini-instruct better for production use?
Both GPT-5.4 mini and Phi-3.5-mini-instruct are production API models. For cost-sensitive production traffic, Phi-3.5-mini-instruct 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-5.4 mini and Phi-3.5-mini-instruct in my app?
Yes. Call GPT-5.4 mini through OpenAI and Phi-3.5-mini-instruct through Microsoft 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-5.4 mini vs Phi-3.5-mini-instruct pricing data?
List rates are the latest published OpenAI API pricing and Microsoft API pricing, quoted per million tokens. Official rate sheets: https://developers.openai.com/api/docs/pricing and https://azure.microsoft.com/en-us/pricing/details/cognitive-services/openai-service/. 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-5.4 mini and Phi-3.5-mini-instruct?
GPT-5.4 mini supports up to 128K output tokens per request, while Phi-3.5-mini-instruct supports up to 128K 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-5.4 mini or Phi-3.5-mini-instruct?
Phi-3.5-mini-instruct has a measured throughput of approximately 23 tokens/second. Throughput data for GPT-5.4 mini 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-5.4 mini vs Phi-3.5-mini-instruct comparison?
Use the model pickers at the top of this LLM comparison. Search any model in the index and the URL updates. Open GPT-5.4 mini or Phi-3.5-mini-instruct from the sidebar for the single-model API pricing page, or go back to the LLM pricing table to sort by cheapest blended cost.
