OLMo 2 13B vs Molmo 72B

Compare OLMo 2 13B and Molmo 72B: pricing, performance, context window, latency, and best use cases. Side-by-side comparison on XALEN.

Updated 2026-05-21 · By Abhishek Raj · Our methodology

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Feature OLMo 2 13B Molmo 72B
CategoryOpen SourceVision
Parameters13B72B
Context Window32K128K
Input Price$0.015/1M tokens$0.04/1M tokens
Output Price$0.03/1M tokens$0.08/1M tokens
Latency~120ms~350ms

Choose OLMo 2 13B when:

  • ✓ Research
  • ✓ Custom training
  • ✓ Transparency-required apps
Key Strengths:

Fully open (weights + data), Transparent, Research-friendly

Choose Molmo 72B when:

  • ✓ Visual grounding
  • ✓ Object detection
  • ✓ Research
Key Strengths:

Fully open, Good pointing/grounding, Transparent

Verdict: OLMo 2 13B vs Molmo 72B

For cost efficiency, OLMo 2 13B wins at $0.015/1M input tokens. For speed, OLMo 2 13B is faster at ~120ms. OLMo 2 13B excels at Research while Molmo 72B is better for Visual grounding. Both are available on XALEN through a single API — try them in the Playground to see which fits your workload.

Detailed Analysis

Pricing Comparison

OLMo 2 13B costs $0.015/1M input tokens and $0.03/1M output tokens. Molmo 72B costs $0.04 input and $0.08 output. OLMo 2 13B is 2.7x cheaper on input tokens. XALEN offers batch processing at 50% discount on both models.

Performance & Context

OLMo 2 13B has a 32K context window with ~120ms latency. Molmo 72B offers 128K context at ~350ms. Molmo 72B has the larger context window.

Best For

OLMo 2 13B (Open Source) is optimized for: Research, Custom training, Transparency-required apps. Molmo 72B (Vision) works best for: Visual grounding, Object detection, Research.

Try Both on XALEN

Both models are available through XALEN's OpenAI-compatible API. Switch between them by changing the model parameter:

from xalen import XALEN

client = XALEN(api_key="xln_test_YOUR_KEY")

# Use OLMo 2 13B
response_a = client.chat.completions.create(
    model="olmo-2-13b",
    messages=[{"role": "user", "content": "Your question here"}]
)

# Use Molmo 72B
response_b = client.chat.completions.create(
    model="molmo-72b",
    messages=[{"role": "user", "content": "Your question here"}]
)

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Get API Key Try in Playground

Frequently Asked Questions

Which is better, OLMo 2 13B or Molmo 72B?

OLMo 2 13B (Open Source, 13B) offers Fully open (weights + data). Molmo 72B (Vision, 72B) offers Fully open. Choose OLMo 2 13B for Research or Molmo 72B for Visual grounding.

How much does OLMo 2 13B cost vs Molmo 72B?

OLMo 2 13B: $0.015/1M input, $0.03/1M output. Molmo 72B: $0.04/1M input, $0.08/1M output. Both available on XALEN with batch processing at 50% discount.

Can I use both models on XALEN?

Yes. XALEN provides 200+ models through a single OpenAI-compatible API. Switch between OLMo 2 13B and Molmo 72B by changing the model parameter. No code changes needed.

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Last updated: 2026-05-21. Pricing and specifications may change. Check pricing page for latest rates.