Comparison · Pricing

Llama 3.1 405B vs GPT-4o

Head-to-head API pricing, caching, context windows and real workload math — so you can pick the right model instead of the familiar one.

Prices verified August 20, 2026
Cheaper overall
Llama 3.1 405B
Meta / Llama
Input
$3.50 / M
Output
$3.50 / M
Cache read
Context
128K
GPT-4o
OpenAI
Input
$2.50 / M
Output
$10 / M
Cache read
$1.25
Context
128K

Live cost calculator

Drag the numbers — costs update instantly for both models.

Llama 3.1 405B
/month
GPT-4o
/month

Cost by workload size

Llama 3.1 405B GPT-4o

Price comparison

Feature Llama 3.1 405B GPT-4o
ProviderMeta / LlamaOpenAI
Input / M tokens$3.50$2.50
Output / M tokens$3.50$10
Cached input read$1.25
Context window128K128K
Batch discount−50%
VisionYes
AudioYes
Reasoning tokens

What your workload actually costs

Prices per token hide the real picture. Here are three common workloads computed with AITokenCalculator's own engine (medium reasoning effort, no batch, no cache):

Workload Llama 3.1 405B GPT-4o Cheaper
1,000 in / 300 out $0.00455 $0.0055 Llama 3.1 405B
10,000 in / 2,000 out $0.042 $0.045 Llama 3.1 405B
100,000 in / 20,000 out $0.42 $0.45 Llama 3.1 405B
Monthly @ 1,000 req/day (standard) $1,278.38 $1,369.69 Llama 3.1 405B

Analysis

On input price, GPT-4o wins at $2.50/M — roughly 1.4× cheaper than its rival. Output tells a sharper story: Llama 3.1 405B charges $3.50/M , about 2.9× less than GPT-4o — and output is where chatty and agentic workloads bleed money.

Context capacity differs too: Llama 3.1 405B fits 128K tokens (~96,000 words) versus 128K. If you feed whole documents or codebases, that gap decides feasibility before price even matters.

Open weights vs closed API. Hosted Llama 405B undercuts GPT-4o on price and removes vendor lock-in — you can even self-host. Expect a gap on multimodal polish and tool-calling reliability; strong pick for text-heavy, cost-sensitive pipelines.

Numbers shift as providers reprice — check the full AI model pricing table, then run your own prompt through the calculator preloaded with Llama 3.1 405B or with GPT-4o.

Llama 3.1 405B vs GPT-4o FAQ

Which is cheaper, Llama 3.1 405B or GPT-4o?

Llama 3.1 405B is cheaper for a typical workload (10K input / 2K output tokens): $0.042 vs $0.045 per call for Llama 3.1 405B and GPT-4o respectively.

How do Llama 3.1 405B and GPT-4o prices compare per million tokens?

Llama 3.1 405B costs $3.5/M input and $3.5/M output; GPT-4o costs $2.5/M input and $10/M output. Output prices differ by about 2.9x between the two.

Which has the bigger context window?

Llama 3.1 405B leads with 128K tokens (~96,000 words). GPT-4o offers 128K tokens.

Should I switch from GPT-4o to Llama 3.1 405B?

Open weights vs closed API. Hosted Llama 405B undercuts GPT-4o on price and removes vendor lock-in — you can even self-host. Expect a gap on multimodal polish and tool-calling reliability; strong pick for text-heavy, cost-sensitive pipelines.