GPT Realtime vs Grok 4.20
GPT Realtime and Grok 4.20 are both current production-tier models. Grok 4.20 is meaningfully cheaper at $2 / $6 per 1M. Grok 4.20 has a 2M context window — about 16× the 128k of GPT Realtime. Grok 4.20 leads on coding, reasoning, general knowledge.
Specs side by side
| Metric | OpenAI GPT Realtime | xAI Grok 4.20 |
|---|---|---|
| Input price (per 1M) | $4 | $2 |
| Output price (per 1M) | $16 | $6 |
| Context window | 128k tokens | 2M tokens |
| Speed tier | ultra | balanced |
| Open weights | No | No |
| EU region | Yes | No |
| Free tier | No | No |
| Prompt caching | No | Yes |
| Vision input | No | Yes |
| Extended thinking | No | Yes |
When to choose each
Choose GPT Realtime if…
- Low latency matters (ultra vs balanced)
- EU data residency is required
- You need realtime speech-to-speech
Choose Grok 4.20 if…
- Cost is a priority ($2 / $6 per 1M vs $4 / $16 per 1M)
- You need 2M context (16× more than GPT Realtime)
- You need image input / vision
- Coding is central to your workload
- Reasoning is central to your workload
Benchmark delta
GPT Realtime leads on
GPT Realtime has no meaningful benchmark lead in this pair.
Grok 4.20 leads on
- Coding
- Reasoning
- General knowledge
- Long-context retrieval
- Instruction following
- Tool use
FAQ — GPT Realtime vs Grok 4.20
GPT Realtime vs Grok 4.20 — which is better?
GPT Realtime and Grok 4.20 are both current production-tier models. Grok 4.20 is meaningfully cheaper at $2 / $6 per 1M. Grok 4.20 has a 2M context window — about 16× the 128k of GPT Realtime. Grok 4.20 leads on coding, reasoning, general knowledge. The right pick depends on your use case — see "When to choose each" above for a data-driven decision.
How does GPT Realtime pricing compare to Grok 4.20?
GPT Realtime costs $4 / $16 per 1M vs Grok 4.20 at $2 / $6 per 1M. Grok 4.20 is cheaper on output tokens by roughly 167%. Both support prompt caching, which reduces effective cost by 80-90% on repeat system prompts.
Does GPT Realtime or Grok 4.20 have the bigger context window?
Grok 4.20 has a 2M-token context window — 16× the 128k context of GPT Realtime. Enough for entire codebases, books, or multi-document RAG.
Is there a free tier for GPT Realtime or Grok 4.20?
GPT Realtime: no — Paid-only. Grok 4.20: no — X Premium includes Grok web chat; API is paid.
Which is better for coding — GPT Realtime or Grok 4.20?
Grok 4.20 leads on coding benchmarks (GPT Realtime: 78/100, Grok 4.20: 91/100). For production coding agents also weigh tool-use performance — GPT Realtime scores 84, Grok 4.20 scores 88.