Meta Llama Models Explained: Llama 1, 2, 3 and 4 — What Changed Each Time

⏱ 3 min readUpdated 28 September 2026

Meta’s Llama family is the best-known series of open-weight language models: you can download the model files and run them on your own computer or server. Here is what each generation brought, in plain English.

In this article
  1. Why Llama matters
  2. The timeline
  3. Mixture of experts in one paragraph
  4. Which one should you use?
  5. Limitations to keep in mind

Why Llama matters

  • Open weights: companies can run Llama privately, fine-tune it, and avoid sending data to a third party.
  • An ecosystem: tools like Ollama and llama.cpp, and thousands of fine-tuned variants, grew around it.
  • Free to try: this site’s AI Helper runs Llama models through Cloudflare’s free tier.

The timeline

Release Sizes What was new
Llama 1 — Feb 2023 7B–65B Research-only licence. Showed a 13B model could rival much larger ones when trained on more data. Its weights leaked and kick-started the open-model community.
Llama 2 — Jul 2023 7B, 13B, 70B Licence allowed most commercial use. Chat-tuned versions released. 4K context.
Llama 3 — Apr 2024 8B, 70B Much better quality from far more training data (15T+ tokens) and a larger tokenizer. 8K context.
Llama 3.1 — Jul 2024 8B, 70B, 405B 128K context, multilingual, and the 405B “frontier-class” open model; better tool calling.
Llama 3.2 — Sep 2024 1B, 3B; 11B/90B vision Tiny models for phones and laptops, plus the first Llama models that can read images.
Llama 3.3 — Dec 2024 70B Quality close to 3.1 405B in a 70B model — cheaper and faster to run.
Llama 4 — Apr 2025 Scout, Maverick (Behemoth previewed) Mixture-of-experts design (only part of the model is active per token), native text+image input, and very long context on Scout.

Mixture of experts in one paragraph

Llama 4 Scout is described as 17B active parameters with 16 experts. The model contains many “expert” sub-networks; for each token a router picks a few of them. You get the knowledge of a large model while only computing a fraction of it per token — faster and cheaper, but it still needs enough memory to hold every expert.

Which one should you use?

Need Pick
Laptop, offline, private Llama 3.2 3B or 3.1 8B with Ollama
Best free quality for text Llama 3.3 70B (cloud) — the AI Helper default
Images plus text, long documents Llama 4 Scout
Fine-tuning for a narrow task A small 3.x model with LoRA

Limitations to keep in mind

  • Knowledge cut-off: each model only knows what was in its training data; it does not know newer events.
  • Hallucination: like every LLM it can state wrong facts confidently — see why.
  • Licence: the Llama licence is permissive but not a standard open-source licence; very large companies and some uses have conditions. Read it before shipping a product.
  • Hardware: bigger models need serious GPUs; quantized versions trade a little quality for much less memory.

Compare Llama with other families in the big AI model comparison.

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