GPT-5.4 Pro vs 
Grok 4 Fast (free)
Grok 4 Fast (free) is cheaper than GPT-5.4 Pro at $0/M vs $30/M input tokens.
Written rounds
2 promptsSeven pantry ingredients, one dish, and a name worth saying out loud.
GPT-5.4 Pro: Dragon Pantry Peanut Noodles A fast, sweet-savory noodle dish made from 7 pantry staples. Ingredients 8 oz spaghetti 1/3 cup peanut butter 3 tbsp soy sauce 1 tbsp honey 1 tbsp vegetable oil 1 tsp garlic powder 1/4 tsp red pepper flakes Water for boiling/thinning the sauce doesn’t count.
Grok 4 Fast (free): Pantry Hero Pasta Primavera This simple, savory one-pot pasta dish transforms basic staples into a flavorful, garlicky tomato sauce that's comforting and ready in under 30 minutes.
One month, three habits, someone starting from nothing.
GPT-5.4 Pro: Here’s a simple, beginner-friendly 1-month health and longevity plan built around 3 key areas: Nutrition Movement Recovery (sleep + stress) The goal is consistency, not perfection. Start small and make the habits easy enough to keep.
Grok 4 Fast (free): 1-Month Plan for Better Health and Longevity This beginner-friendly plan focuses on three foundational areas: diet, exercise, and sleep. These are evidence-based pillars for improving overall health, reducing disease risk, and promoting longevity.
Price and specs
Not enough votes to call it. On the specs, GPT-5.4 Pro has the edge: bigger model tier, newer.
| Spec | GPT-5.4 Pro | Grok 4 Fast (free) |
|---|---|---|
| Input price | $30/M tokens | Free |
| Output price | $180/M tokens | Free |
| Context window | 1.1M tokens | 2.0M tokens |
| Weights | Closed | — |
| Free API (OpenRouter) | No | No |
| Released | Mar 2026 | Sep 2025 |
| At 10M a month | $300 | $0 |
Input tokens at list price. No caching, no batch discount.
Where to run it
Grok 4 Fast (free)
No hosts listed on OpenRouter.
Per million tokens. Prices and uptime via OpenRouter, checked 13 Oct 2026.
Common questions
What is the difference between GPT-5.4 Pro and Grok 4 Fast (free)?
GPT-5.4 Pro is developed by OpenAI while Grok 4 Fast (free) is developed by xAI. GPT-5.4 Pro has a 1.1M token context window vs Grok 4 Fast (free)'s 2.0M. You can compare their actual outputs across 2 challenges on Rival to see how they differ in practice.
Which is better, GPT-5.4 Pro or Grok 4 Fast (free)?
It depends on your use case. GPT-5.4 Pro and Grok 4 Fast (free) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 2 challenges so you can judge which fits your needs best.
How much does GPT-5.4 Pro cost compared to Grok 4 Fast (free)?
GPT-5.4 Pro costs $30/M input tokens and Grok 4 Fast (free) costs $0/M input tokens. Grok 4 Fast (free) is $30.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.
How can I compare GPT-5.4 Pro and Grok 4 Fast (free) on Rival?
This page shows a side-by-side comparison of GPT-5.4 Pro and Grok 4 Fast (free) across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.
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