GPT-5.4 Nano vs Grok 4.20
GPT-5.4 Nano (2026) and Grok 4.20 (2026) are frontier reasoning models from OpenAI and xAI. GPT-5.4 Nano ships a 400K-token context window, while Grok 4.20 ships a 2M-token context window. On pricing, GPT-5.4 Nano costs $0.2/1M input tokens versus $1.25/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
GPT-5.4 Nano is ~525% cheaper at $0.2/1M; pay for Grok 4.20 only for reasoning depth.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-03-05 | 2026-01-01 |
| Context window | 400K | 2M |
| Parameters | — | — |
| Architecture | decoder only | - |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-08 | - |
Pricing and availability
| Pricing attribute | GPT-5.4 Nano | Grok 4.20 |
|---|---|---|
| Input price | $0.2/1M tokens | $1.25/1M tokens |
| Output price | $1.25/1M tokens | $2.5/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.4 Nano | Grok 4.20 |
|---|---|---|
| Vision | No | No |
| Multimodal | Yes | No |
| Reasoning | No | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on multimodal input: GPT-5.4 Nano, reasoning mode: Grok 4.20, and code execution: GPT-5.4 Nano. Both models share function calling, tool use, and structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, GPT-5.4 Nano lists $0.2/1M input and $1.25/1M output tokens, while Grok 4.20 lists $1.25/1M input and $2.5/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts GPT-5.4 Nano lower by about $1.11 per million blended tokens. Availability is 2 providers versus 2, so concentration risk also matters.
Choose GPT-5.4 Nano when coding workflow support and lower input-token cost are central to the workload. Choose Grok 4.20 when reasoning depth and larger context windows are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Which has a larger context window, GPT-5.4 Nano or Grok 4.20?
Grok 4.20 supports 2M tokens, while GPT-5.4 Nano supports 400K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, GPT-5.4 Nano or Grok 4.20?
GPT-5.4 Nano is cheaper on tracked token pricing. GPT-5.4 Nano costs $0.2/1M input and $1.25/1M output tokens. Grok 4.20 costs $1.25/1M input and $2.5/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is GPT-5.4 Nano or Grok 4.20 open source?
GPT-5.4 Nano is listed under Proprietary. Grok 4.20 is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for multimodal input, GPT-5.4 Nano or Grok 4.20?
GPT-5.4 Nano has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for reasoning mode, GPT-5.4 Nano or Grok 4.20?
Grok 4.20 has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run GPT-5.4 Nano and Grok 4.20?
GPT-5.4 Nano is available on OpenAI API and OpenRouter. Grok 4.20 is available on xAI Console and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-14. Data sourced from public model cards and provider documentation.