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Meta Llama 3.1 405B Instruct vs OpenAI GPT-OSS 20B

On provider list prices, OpenAI GPT-OSS 20B costs $0.05 per million input tokens against $3.50 for Meta Llama 3.1 405B Instruct: 70.0x apart. Output is $0.20 against $3.50 (17.5x). On Allocate both bill at list plus the 7% transaction fee.

Meta Llama 3.1 405B Instruct OpenAI GPT-OSS 20B
LabMetaOpenAI
AccessOpen weightsOpen weights
Context window4K tokens128K tokens
List price, input$3.5 / M tokens$0.05 / M tokens
List price, output$3.5 / M tokens$0.2 / M tokens
Cached inputn/an/a
LicenseLlama communityApache 2.0
Fine-tunableYesYes

Specifications and provider list prices from the Allocate catalog, checked 2026-07-08. Billed price is list plus the 7% transaction fee.

What the numbers say

Take 1,000,000 requests a month at 1,200 input and 350 output tokens each. That workload costs $130 a month on OpenAI GPT-OSS 20B and $5,425 on Meta Llama 3.1 405B Instruct at list: a gap of $5,295, or 41.7x.

OpenAI GPT-OSS 20B reads 128K tokens per request against 4K for Meta Llama 3.1 405B Instruct, 32.0x the window. That decides which one can take whole documents without splitting them.

OpenAI GPT-OSS 20B$0.05$0.20
Meta Llama 3.1 405B Instruct$3.50$3.50
InputOutput

Choose Meta Llama 3.1 405B Instruct for

  • Training toward a model you own
Meta Llama 3.1 405B Instruct details

Choose OpenAI GPT-OSS 20B for

  • The lower list price ($0.05 in / $0.20 out per M tokens)
  • The longer context window (128K vs 4K tokens)
  • Fine-tuning under a permissive license (Apache 2.0)
OpenAI GPT-OSS 20B details

Common questions

Which is cheaper, Meta Llama 3.1 405B Instruct or OpenAI GPT-OSS 20B?

OpenAI GPT-OSS 20B, on this workload shape. At list prices it is $0.05/$0.20 per million tokens in and out against $3.50/$3.50 for Meta Llama 3.1 405B Instruct. Billed on Allocate: $0.053/$0.21 against $3.75/$3.75, list plus 7%.

Which has the bigger context window?

OpenAI GPT-OSS 20B: 131,072 tokens (128K) against 4,096 (4K) for Meta Llama 3.1 405B Instruct.

Can I fine-tune Meta Llama 3.1 405B Instruct or OpenAI GPT-OSS 20B?

Both publish open weights (Meta Llama 3.1 405B Instruct: Llama community; OpenAI GPT-OSS 20B: Apache 2.0), so both can be fine-tuned. On Allocate the trained weights stay inside your boundary and belong to you.

Related comparisons

Meta Llama 3.1 405B Instruct vs Meta Llama 3.3 70B Instruct TurboOpenAI GPT-OSS 20B vs Meta Llama 3.3 70B Instruct TurboMeta Llama 3.1 405B Instruct vs Llama 4 Scout Instruct (17Bx16E)OpenAI GPT-OSS 20B vs Llama 4 Scout Instruct (17Bx16E)Meta Llama 3.1 405B Instruct vs OpenAI GPT-OSS 120BOpenAI GPT-OSS 20B vs OpenAI GPT-OSS 120B

Run the numbers on your workload

LLM price comparisonAgent cost calculatorMeta Llama 3.1 405B InstructOpenAI GPT-OSS 20B

Or don’t choose. On Allocate a route name is the contract: point yours at one model today, swap to the other tomorrow, and compare them on your live traffic with per-token metering.

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