Claude Opus 5 vs Grok 4.1 Fast
Pricing & Specs
Anthropic vs xAI, side by side from a live registry. Specs below, then benchmark both on your own task.
TL;DR: On a typical task (1K input + 500 output tokens), Grok 4.1 Fast is about 38.9x cheaper than Claude Opus 5. But per-token price is not cost per result: a cheaper model that needs more tokens, retries, or hand-holding can end up more expensive on your workload. The specs below are facts; which one is better at YOUR task is measurable, not guessable.
API Pricing: Claude Opus 5 vs Grok 4.1 Fast
| Tokens | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| Input | $5 / 1M | $0.2 / 1M |
| Output | $25 / 1M | $0.5 / 1M |
| Cached input | $0.5 / 1M | $0.05 / 1M |
What that means in practice (1K input + 500 output tokens)
Specs Compared
| Spec | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| Context window | 1M tokens | 2M tokens |
| Max output tokens | 128K tokens | - |
| Input modalities | text, image | text, image |
| Knowledge cutoff | - | - |
| Latency (measured) | - | ~1.4s median response |
| Reasoning model | Yes | Yes |
| Tool / function calling | Yes | Yes |
| JSON mode | Yes | Yes |
| Prompt caching | Yes | Yes |
When to Choose Which
FAQ
Which is cheaper, Claude Opus 5 or Grok 4.1 Fast?
Claude Opus 5 costs $5/$25 per 1M input/output tokens; Grok 4.1 Fast costs $0.2/$0.5. On a typical task (1K input + 500 output tokens), Grok 4.1 Fast is about 38.9x cheaper than Claude Opus 5.
Which has the bigger context window, Claude Opus 5 or Grok 4.1 Fast?
Claude Opus 5 has a 1M-token context window; Grok 4.1 Fast has 2M tokens.
Is Claude Opus 5 better than Grok 4.1 Fast?
It depends on the task. Generic leaderboards won't tell you which one wins on YOUR workload. OpenMark lets you benchmark Claude Opus 5 and Grok 4.1 Fast head to head on your own task with real API calls, no API keys needed, free tier available.
Claude Opus 5 or Grok 4.1 Fast for YOUR Task?
Spec tables can't answer that. Run both head to head on your actual workload:
real API calls, ranked results with accuracy, cost, and latency. Free tier available.