GPT-5 Nano vs GPT-5.3 Codex
At a Glance
| Compare |  GPT-5 NanoOpenAI | GPT-5.3 CodexOpenAI |
|---|---|---|
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $0.025Openrouter ↗ · Sep 3, 2026 | $1.75Openai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $0.20Openrouter ↗ · Sep 3, 2026 | $14.00Openai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 400K | 400K |
| Model facts checked | Sep 3, 2026View model evidence → | Sep 3, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
Side-by-Side Facts
| Field | GPT-5 Nano | GPT-5.3-Codex |
|---|---|---|
| Developer | OpenAI | OpenAI |
| Family | Gpt 5 | Gpt 5 3 |
| Model | GPT-5 Nano | GPT-5.3-Codex |
| Version | GPT-5 Nano | GPT-5.3-Codex |
| Lifecycle | active | active |
| Released | 2025-08-07 | Unknown |
| Knowledge cutoff | 2024-05-31 | 2025-08-31 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 400K | 400K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Openai (Standard), Openrouter (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, structured_outputs, tools | chat, generation, reasoning, structured_outputs, tools |
GPT-5 Nano Capabilities
GPT-5.3 Codex Capabilities
Related Comparisons
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|---|---|---|---|
GPT-5 NanoOpenAI | vs | Grok 4.6xAI | cross-developer peersimage, text |
Claude Sonnet 5Anthropic | vs | GPT-5 NanoOpenAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs | GPT-5 NanoOpenAI | cross-developer peersimage, text |
Seed 2.0 CodeByteDance Seed | vs | GPT-5 NanoOpenAI | cross-developer peerstext |
GPT-4.1 NanoOpenAI | vs | GPT-5 NanoOpenAI | family variantsimage, text |
GPT-5 NanoOpenAI | vs | GPT-5.4 NanoOpenAI | family variantsimage, text |
GPT-5 NanoOpenAI | vs | GPT-5.6 SolOpenAI | family variantsimage, text |
GPT-5 NanoOpenAI | vs |  Sonar Deep ResearchPerplexity | cross-developer peerstext |
GPT-5 NanoOpenAI | vs | Sonar Reasoning ProPerplexity | cross-developer peerstext |
GPT-5 NanoOpenAI | vs |  Qwen3 VL PlusQwen | cross-developer peersimage, text |
GPT-5 NanoOpenAI | vs | Grok 4.5xAI | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
GPT-5 Nano vs GPT-5.3 Codex FAQs
Is GPT-5 Nano or GPT-5.3 Codex better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both GPT-5 Nano and GPT-5.3 Codex, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, GPT-5 Nano or GPT-5.3 Codex?+
GPT-5 Nano is $0.025 and GPT-5.3 Codex is $1.75 per million tokens, so GPT-5 Nano is cheaper on this metric. GPT-5 Nano is $0.20 and GPT-5.3 Codex is $14.00 per million tokens, so GPT-5 Nano is cheaper on this metric.
Which has a larger context window, GPT-5 Nano or GPT-5.3 Codex?+
Both models have the same sourced context window: 400,000 tokens each.
Which performs better in benchmarks, GPT-5 Nano or GPT-5.3 Codex?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can GPT-5 Nano or GPT-5.3 Codex be self-hosted?+
Both models have the same sourced self-hosting status: unsupported. GPT-5 Nano is not marked open weight; GPT-5.3 Codex is not marked open weight.
Can GPT-5 Nano and GPT-5.3 Codex understand images?+
GPT-5 Nano is documented with image input; GPT-5.3 Codex is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, GPT-5 Nano or GPT-5.3 Codex?+
Both models have the same sourced maximum output: 128,000 tokens each.
Do GPT-5 Nano and GPT-5.3 Codex support reasoning and tool use?+
GPT-5 Nano: reasoning, tool calling, and image input. GPT-5.3 Codex: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, GPT-5 Nano or GPT-5.3 Codex?+
GPT-5 Nano has 2 sourced provider routes; GPT-5.3 Codex has 2, a tie.
Which offers better value, GPT-5 Nano or GPT-5.3 Codex?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.