Grok 3 vs GPT-5 Nano: Detailed Comparison
Choosing between Grok 3 (xAI) and
GPT-5 Nano (OpenAI) comes down to three things:
per-token pricing, context window, and which capability matters most for your workload.
Grok 3 costs $3.00/M input vs
$0.05/M for GPT-5 Nano;
context windows are 1.0M vs
400K tokens. Detailed breakdown below.
Side-by-side specs
| Spec | Grok 3 | GPT-5 Nano |
|---|
| Provider | xAI | OpenAI |
|---|
| Released | 2025-02-17 | 2025-08-07 |
|---|
| Input price |
$3.00/M |
$0.05/M |
| Output price |
$15.00/M |
$0.40/M |
| Cached input |
— |
$0.0050/M |
| Context window |
1.0M |
400K |
| Max output |
16K |
64K |
| Modalities |
text image |
text |
| Tokenizer |
grok |
o200k_base |
Capability matrix
| Capability | Grok 3 | GPT-5 Nano |
|---|
| function calling |
Yes |
Yes |
| json mode |
Yes |
Yes |
| vision |
Yes |
No |
| streaming |
Yes |
Yes |
| realtime web |
Yes |
No |
Benchmark comparison
Higher is better for all benchmarks shown.
Per-call cost on typical workloads
| Workload (in/out tokens) | Grok 3 | GPT-5 Nano | Cheaper by |
|---|
| Standard chat (1K / 500) |
$0.010500 |
$0.000250 |
GPT-5 Nano by $0.010250 |
| RAG (4K / 500) |
$0.019500 |
$0.000400 |
GPT-5 Nano by $0.019100 |
| Long doc (20K / 1K) |
$0.075000 |
$0.001400 |
GPT-5 Nano by $0.073600 |
| Very long context (100K / 2K) |
$0.322500 |
$0.005600 |
GPT-5 Nano by $0.316900 |
When to choose Grok 3 over GPT-5 Nano
- Larger context window (1.0M vs 400K) — relevant when whole documents or long histories must fit in a single call.
- Supports vision — GPT-5 Nano does not.
- Supports realtime web — GPT-5 Nano does not.
When to choose GPT-5 Nano over Grok 3
- Per-token input cost is 98% lower than Grok 3.
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