GPT-5 vs Grok 3: Detailed Comparison
Choosing between GPT-5 (OpenAI) and
Grok 3 (xAI) comes down to three things:
per-token pricing, context window, and which capability matters most for your workload.
GPT-5 costs $1.25/M input vs
$3.00/M for Grok 3;
context windows are 400K vs
1.0M tokens. Detailed breakdown below.
Side-by-side specs
| Spec | GPT-5 | Grok 3 |
|---|
| Provider | OpenAI | xAI |
|---|
| Released | 2025-08-07 | 2025-02-17 |
|---|
| Input price |
$1.25/M |
$3.00/M |
| Output price |
$10.00/M |
$15.00/M |
| Cached input |
$0.1300/M |
— |
| Context window |
400K |
1.0M |
| Max output |
128K |
16K |
| Modalities |
text image |
text image |
| Tokenizer |
o200k_base |
grok |
Capability matrix
| Capability | GPT-5 | Grok 3 |
|---|
| function calling |
Yes |
Yes |
| json mode |
Yes |
Yes |
| vision |
Yes |
Yes |
| streaming |
Yes |
Yes |
| reasoning |
Yes |
No |
| realtime web |
No |
Yes |
Benchmark comparison
Higher is better for all benchmarks shown.
Per-call cost on typical workloads
| Workload (in/out tokens) | GPT-5 | Grok 3 | Cheaper by |
|---|
| Standard chat (1K / 500) |
$0.006250 |
$0.010500 |
GPT-5 by $0.004250 |
| RAG (4K / 500) |
$0.010000 |
$0.019500 |
GPT-5 by $0.009500 |
| Long doc (20K / 1K) |
$0.035000 |
$0.075000 |
GPT-5 by $0.040000 |
| Very long context (100K / 2K) |
$0.140000 |
$0.322500 |
GPT-5 by $0.182500 |
When to choose GPT-5 over Grok 3
- Per-token input cost is 58% lower — meaningful for high-volume workloads.
- Supports reasoning — Grok 3 does not.
When to choose Grok 3 over GPT-5
- Larger context window (1.0M vs 400K).
- Supports realtime web — GPT-5 does not.
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