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Comparison · 2 models · Updated Nov 2, 2026

GPT OSS 20B vs Claude Haiku 4.5

GPT OSS 20B comes out ahead, 61 to 57 on our weighted score, and it is the cheaper option too.

  1. Our pick

    OpenAI

    GPT OSS 20B

    Released Aug 5, 2025

    61/100
    • ECI137.8
    • Price$0.07 / $0.25
    • Context131K
    Full specs Remove GPT OSS 20B

  2. Anthropic

    Claude Haiku 4.5

    Released Oct 15, 2025

    57/100
    • ECI142.2
    • Price$1.00 / $5.00
    • Context200K
    Full specs Remove Claude Haiku 4.5

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01 — Verdict

GPT OSS 20B is our pick

GPT OSS 20B is the better all-round choice, scoring 61/100 against Claude Haiku 4.5 (57). It leads on price. Claude Haiku 4.5 wins on capability, inputs & features and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityClaude Haiku 4.5Capabilities Index (ECI): Claude Haiku 4.5 142.2 · GPT OSS 20B 137.8
  • Lowest priceGPT OSS 20BGPT OSS 20B $0.115 · Claude Haiku 4.5 $2.00 per 1M tokens (3:1 blend)
  • Longest contextClaude Haiku 4.5Claude Haiku 4.5 200,000 · GPT OSS 20B 131,072 tokens
  • Widest inputsClaude Haiku 4.5GPT OSS 20B: Text · Claude Haiku 4.5: Text, Images, PDFs
  • Self-hostingGPT OSS 20BPublishes downloadable weights
How the score is built
MeasureWeightGPT OSS 20BClaude Haiku 4.5
CapabilityCapabilities Index (ECI)50%6167
Price25%9034
Inputs & features15%3580
Context window10%2532
Overall100%61/10057/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

GPT OSS 20B vs Claude Haiku 4.5 specifications side by side
SpecificationGPT OSS 20BOpenAIClaude Haiku 4.5Anthropic
Capability
Capabilities Index (ECI)137.8142.2 (best)
ECI rank#122 of 165#102 of 165 (best)
GPQA DiamondGraduate-level science questions60.8%71.2% (best)
OTIS Mock AIME 2024–2025Competition mathematics65.3%66.7% (best)
SimpleQA VerifiedShort factual questions—13.2%
Price per million tokens
Input$0.07 (best)$1.00
Output$0.25 (best)$5.00
Cached input—$0.10
Blended (3:1)$0.115 (best)$2.00
Long-context rateSame rateSame rate
Price sourceMedian of 37 providersOfficial Anthropic API
Limits
Context window131,072 tokens200,000 tokens (best)
Max output32,768 tokens64,000 tokens (best)
Inputs and features
TextYesYes
ImagesNoYes
PDFsNoYes
AudioNoNo
VideoNoNo
ReasoningYesYes
Tool callingYesYes
Structured outputNoYes
Availability
WeightsOpenProprietary
API model ID—claude-haiku-4-5
API providers4148 (best)
ReleasedAug 5, 2025Oct 15, 2025
Knowledge cutoffJun 2024Feb 28, 2025
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • GPT OSS 20B$1.20
  • Claude Haiku 4.5$20.00
04 — Questions

Which should you choose?

Which is better: GPT OSS 20B or Claude Haiku 4.5?

GPT OSS 20B is the better all-round choice, scoring 61/100 against Claude Haiku 4.5 (57). It leads on price. Claude Haiku 4.5 wins on capability, inputs & features and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT OSS 20B or Claude Haiku 4.5?

GPT OSS 20B is cheaper at $0.07 input / $0.25 output per million tokens (median across 37 API providers). Claude Haiku 4.5 costs $1.00 input / $5.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $0.115 per million tokens for GPT OSS 20B versus $2.00 for Claude Haiku 4.5 (17× as much).

Which scores higher on benchmarks?

Claude Haiku 4.5 scores higher on the Capabilities Index (ECI): Claude Haiku 4.5 142.2 (#102 of 165) and GPT OSS 20B 137.8 (#122 of 165). The confidence ranges of the top two overlap (139.4–143.9 vs 133.1–139.7), so treat the gap as small. On individual benchmarks: GPQA Diamond — Claude Haiku 4.5 71.2%, GPT OSS 20B 60.8%; OTIS Mock AIME 2024–2025 — Claude Haiku 4.5 66.7%, GPT OSS 20B 65.3%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT OSS 20B and Claude Haiku 4.5 yet, so there is no like-for-like coding score. On overall capability, Claude Haiku 4.5 leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Which has the bigger context window?

Claude Haiku 4.5 has the largest context window at 200,000 tokens, against 131,072 for GPT OSS 20B. Maximum output per response: GPT OSS 20B up to 32,768, Claude Haiku 4.5 up to 64,000 tokens.

Which can read images, PDFs, audio or video?

GPT OSS 20B accepts text; Claude Haiku 4.5 accepts text, images and PDFs. Claude Haiku 4.5 handles the widest range of inputs.

Are any of these open source?

GPT OSS 20B publishes its weights and can be self-hosted; Claude Haiku 4.5 is proprietary.

Which is newer?

Claude Haiku 4.5 is the newest, released Oct 15, 2025. GPT OSS 20B came out Aug 5, 2025. Knowledge cutoff: GPT OSS 20B Jun 2024, Claude Haiku 4.5 Feb 28, 2025.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.

05 — Keep comparing

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