# Meta Llama 3.1 405B Instruct vs Grok 4.5

On provider list prices, Meta Llama 3.1 405B Instruct costs $3.50 per million input tokens against $2 for Grok 4.5: effectively level. Output is $3.50 against $6 (1.7x).

## Specifications

| | Meta Llama 3.1 405B Instruct | Grok 4.5 |
| --- | --- | --- |
| Lab | Meta | SpaceXAI |
| Access | Open weights | API only |
| Context window | 4K tokens | 500K tokens |
| List price, input | $3.50 / M tokens | $2 / M tokens |
| List price, output | $3.50 / M tokens | $6 / M tokens |
| Cached input | n/a | $0.30 / M tokens |
| License | Llama community | Proprietary API |
| Fine-tunable | Yes | No |

Specifications and provider list prices from the Allocate catalog, checked 2026-07-21.

## What the numbers say

Take 1,000,000 requests a month at 1,200 input and 350 output tokens each. That workload costs $4,500 a month on Grok 4.5 and $5,425 on Meta Llama 3.1 405B Instruct at list: a gap of $925, or 1.2x.

Grok 4.5 reads 500K tokens per request against 4K for Meta Llama 3.1 405B Instruct, 122.1x the window. That decides which one can take whole documents without splitting them.

## Choose Meta Llama 3.1 405B Instruct for

- Open weights you can fine-tune and own

## Choose Grok 4.5 for

- The lower list price ($2 in / $6 out per M tokens)
- The longer context window (500K vs 4K tokens)
- Published cached-input pricing ($0.30 per M tokens)

## Common questions

### Which is cheaper, Meta Llama 3.1 405B Instruct or Grok 4.5?

Grok 4.5, on this workload shape. At list prices it is $2/$6 per million tokens in and out against $3.50/$3.50 for Meta Llama 3.1 405B Instruct. Billed on Allocate: $2.14/$6.42 against $3.75/$3.75.

### Which has the bigger context window?

Grok 4.5: 500,000 tokens (500K) against 4,096 (4K) for Meta Llama 3.1 405B Instruct.

### Can I fine-tune Meta Llama 3.1 405B Instruct or Grok 4.5?

Meta Llama 3.1 405B Instruct publishes open weights (Llama community) and can be fine-tuned on your own data. Grok 4.5 is a closed model served over API; its weights are not available.

---

[HTML page](https://allocate.network/compare/meta-llama-3-1-405b-instruct-vs-xai-grok-4-5) · [Meta Llama 3.1 405B Instruct](https://allocate.network/models/meta-llama-3-1-405b-instruct.md) · [Grok 4.5](https://allocate.network/models/xai-grok-4-5.md) · [Machine-readable catalog](https://allocate.network/catalog.json)