Claude Sonnet 4.5 vs Grok 4-20
Complete pricing and performance comparison between Anthropic's Claude Sonnet 4.5 and xAI's Grok 4-20.
Quick Verdict
Cheaper
Grok 4-20
1.5x cheaper input, 2.5x cheaper output
Larger Context
Claude Sonnet 4.5
200K vs 131K
Pricing Comparison
| Spec | Claude Sonnet 4.5 | Grok 4-20 | Difference |
|---|---|---|---|
| Provider | Anthropic | xAI | |
| Input / 1M tokens | $3 | $2 | Grok 4-20 is 33% more expensive |
| Output / 1M tokens | $15 | $6 | Grok 4-20 is 60% more expensive |
| Context Window | 200K | 131K | 2x difference |
| Max Output | 64K | 16K |
Performance Benchmarks
| Metric | Claude Sonnet 4.5 | Grok 4-20 | Winner |
|---|---|---|---|
| Quality Index | -- | 49 | N/A |
| Output Speed | -- | 101 tok/s | N/A |
| Value (Quality/$) | -- | 24.3 | Higher = better value |
Benchmark data from Artificial Analysis. Quality Index is a composite score across reasoning, coding, and knowledge tasks.
Cost at Scale
Estimated cost at different usage levels (3:1 input-to-output token ratio, typical for chat).
| Usage | Claude Sonnet 4.5 | Grok 4-20 | Savings |
|---|---|---|---|
Single request 1K in / 300 out | $0.0075 | $0.0038 | Grok 4-20 saves $0.0037 |
10 requests 10K in / 3K out | $0.075 | $0.038 | Grok 4-20 saves $0.037 |
100 requests 100K in / 30K out | $0.750 | $0.380 | Grok 4-20 saves $0.370 |
1,000 requests 1M in / 300K out | $7.50 | $3.80 | Grok 4-20 saves $3.70 |
10,000 requests 10M in / 3M out | $75.00 | $38.00 | Grok 4-20 saves $37.00 |
1M requests/mo 1B in / 300M out | $7500.00 | $3800.00 | Grok 4-20 saves $3700.00 |
Pros & Cons
Claude Sonnet 4.5 Strengths
- +Larger context window (200K vs 131K)
- +Higher max output tokens
Grok 4-20 Strengths
- +Cheaper input tokens
- +Cheaper output tokens
When to Use Each Model
Choose Claude Sonnet 4.5 for
- →Long documents, large codebases, or multi-turn conversations
- →Generating long-form content or detailed code
Choose Grok 4-20 for
- →Budget-conscious projects where cost is the primary factor
Frequently Asked Questions
Which is cheaper, Claude Sonnet 4.5 or Grok 4-20?
For input tokens, Grok 4-20 is 1.5x cheaper at $2/1M tokens. For output tokens, Grok 4-20 is 2.5x cheaper at $6/1M tokens. At typical usage (1M input + 300K output), Claude Sonnet 4.5 costs $7.50 vs Grok 4-20 at $3.80.
What's the context window difference?
Claude Sonnet 4.5 supports 200K context (200,000 tokens), while Grok 4-20 supports 131K (131,072 tokens). Claude Sonnet 4.5 can handle 2x more context in a single request.
Which model has better benchmarks?
When should I choose Claude Sonnet 4.5 over Grok 4-20?
Choose Claude Sonnet 4.5 when you need: Larger context window (200K vs 131K), Higher max output tokens. Choose Grok 4-20 when you need: Cheaper input tokens, Cheaper output tokens.
How much would 10,000 API requests cost?
At 1K input + 300 output tokens per request (typical chat): Claude Sonnet 4.5 = $75.00, Grok 4-20 = $38.00. At 10K input + 1K output per request (longer conversations): Claude Sonnet 4.5 = $450.00, Grok 4-20 = $260.00.
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