As of August 25, 2026, GPT-5.1 Instant is 85% cheaper per million tokens than o1. GPT-5.1 Instant is $1.25 / $10.00 per million input/output tokens versus o1 at $15.00 / $60.00. Source: https://developers.openai.com/api/docs/pricing
Source: OpenAI API pricing (https://developers.openai.com/api/docs/pricing)
GPT-5.1 Instant
OpenAI
Input
$1.25
Output
$10.00
o1
OpenAI
Input
$15.00
Output
$60.00
Token pricing, specs, and benchmarks side by side
Each bar is share of the current leader on that eval. Click a row to open the board.
SWE-bench Verified. Left is cheaper. Up is a higher score. The line is the best score you can buy at each price.
GPT-5.1 Instanto1Verdict
GPT-5.1 Instant offers both lower pricing and stronger benchmark performance across the board, making it the clear value leader in this comparison.
As of August 25, 2026, GPT-5.1 Instant is 85% cheaper on blended LLM API pricing. GPT-5.1 Instant costs $1.25 per million input tokens and $10.00 per million output tokens ($11.25 blended 1M-in + 1M-out). o1 costs $15.00 / $60.00 per million tokens ($75.00 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.
GPT-5.1 Instant OpenAI API pricing is $1.25 input and $10.00 output per million tokens via OpenAI. o1 OpenAI API pricing is $15.00 input and $60.00 output per million tokens via OpenAI. Use those four numbers, not ChatGPT Plus or Claude Pro subscription prices, when you are comparing APIs.
GPT-5.1 Instant leads on SWE-bench Verified: GPT-5.1 Instant at 76.3% vs o1 at 41%. SWE-bench measures real GitHub fixes; LiveCodeBench measures contest programming.
GPT-5.1 Instant supports a 400K token context window, while o1 supports 200K tokens. GPT-5.1 Instant 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.
GPT-5.1 Instant leads on 6 of 7 shared benchmarks versus o1's 1 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.
Both GPT-5.1 Instant and o1 are production API models. For cost-sensitive production traffic, GPT-5.1 Instant 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.
Yes. Call GPT-5.1 Instant through OpenAI and o1 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.
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.
GPT-5.1 Instant supports up to 128K output tokens per request, while o1 supports up to 100K output tokens. Output tokens are usually the expensive half of API pricing, so a higher max output cap is a capability, not a discount.
GPT-5.1 Instant runs at approximately 100 tokens/second while o1 runs at 16 tokens/second. GPT-5.1 Instant is faster in raw throughput. 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.
Use the model pickers at the top of this LLM comparison. Search any model in the index and the URL updates. Open GPT-5.1 Instant or o1 from the sidebar for the single-model API pricing page, or go back to the LLM pricing table to sort by cheapest blended cost.
This comparison covers API pricing, context window, throughput, and benchmark scores. GPT-5.1 Instant costs $1.25/M input and $10.00/M output. o1 costs $15.00/M input and $60.00/M output.
Rank both on the LLM leaderboard, SWE-bench, and Humanity's Last Exam.
The index
280 models across 33 providers. Search or jump to a lab — every model page stays linked here.
Next step
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