As of August 20, 2026, GPT-5 nano is 96% cheaper per million tokens than GPT-5 Codex. GPT-5 Codex is $1.25 / $10.00 per million input/output tokens versus GPT-5 nano at $0.05 / $0.40. Source: https://developers.openai.com/api/docs/pricing
Source: OpenAI API pricing (https://developers.openai.com/api/docs/pricing)
GPT-5 Codex
OpenAI
Input
$1.25
Output
$10.00
GPT-5 nano
OpenAI
Input
$0.05
Output
$0.40
Token pricing, specs, and benchmarks side by side
GPT-5 CodexGPT-5 nanoVerdict
GPT-5 nano offers significantly lower pricing, while GPT-5 Codex leads on benchmark performance. Your choice depends on whether cost efficiency or raw capability matters more for your use case.
As of August 20, 2026, GPT-5 nano is 96% cheaper on blended LLM API pricing. GPT-5 nano costs $0.05 per million input tokens and $0.40 per million output tokens ($0.45 blended 1M-in + 1M-out). GPT-5 Codex costs $1.25 / $10.00 per million tokens ($11.25 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 Codex OpenAI API pricing is $1.25 input and $10.00 output per million tokens via OpenAI. GPT-5 nano OpenAI API pricing is $0.05 input and $0.40 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 Codex leads on SWE-bench Verified: GPT-5 Codex at 74.5% vs GPT-5 nano at 34.8%. SWE-bench measures real GitHub fixes; LiveCodeBench measures contest programming.
GPT-5 Codex supports a 400K token context window, while GPT-5 nano supports 400K tokens. Both models have the same context window size. Filling a larger window bills more input tokens, so the cheaper-per-million model can still cost more on long documents.
GPT-5 Codex leads on 3 of 3 shared benchmarks versus GPT-5 nano'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.
Both GPT-5 Codex and GPT-5 nano are production API models. For cost-sensitive production traffic, GPT-5 nano 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 Codex through OpenAI and GPT-5 nano 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 Codex supports up to an unspecified number of output tokens per request, while GPT-5 nano 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.
GPT-5 nano has a measured throughput of approximately 500 tokens/second. Throughput data for GPT-5 Codex 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.
Use the model pickers at the top of this LLM comparison. Search any model in the index and the URL updates. Open GPT-5 Codex or GPT-5 nano 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 Codex costs $1.25/M input and $10.00/M output. GPT-5 nano costs $0.05/M input and $0.40/M output.
Rank both on the LLM leaderboard, SWE-bench, and Humanity's Last Exam.
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