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Comparison · 2 models · Updated Oct 4, 2026

GPT OSS 120B vs GPT-5 Nano

GPT-5 Nano comes out ahead, 70 to 61 on our weighted score, and it is the cheaper option too.

  1. OpenAI

    GPT OSS 120B

    Released Aug 5, 2025

    61/100
    • ECI140.0
    • Price$0.15 / $0.60
    • Context131K
    Full specs Remove GPT OSS 120B
  2. Our pick

    OpenAI

    GPT-5 Nano

    Released Aug 7, 2025

    70/100
    • ECI139.4
    • Price$0.05 / $0.40
    • Context400K
    Full specs Remove GPT-5 Nano

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT-5 Nano is our pick

GPT-5 Nano is the better all-round choice, scoring 70/100 against GPT OSS 120B (61). It leads on price, inputs & features and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT OSS 120BCapabilities Index (ECI): GPT OSS 120B 140.0 · GPT-5 Nano 139.4
  • Lowest priceGPT-5 NanoGPT-5 Nano $0.138 · GPT OSS 120B $0.263 per 1M tokens (3:1 blend)
  • Longest contextGPT-5 NanoGPT-5 Nano 400,000 · GPT OSS 120B 131,072 tokens
  • Widest inputsGPT-5 NanoGPT OSS 120B: Text · GPT-5 Nano: Text, Images
  • Self-hostingGPT OSS 120BPublishes downloadable weights
How the score is built
MeasureWeightGPT OSS 120BGPT-5 Nano
CapabilityCapabilities Index (ECI)50%6565
Price25%7791
Inputs & features15%4570
Context window10%2444
Overall100%61/10070/100
02 — Side by side

Every spec in one table

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

GPT OSS 120B vs GPT-5 Nano specifications side by side
SpecificationGPT OSS 120BOpenAIGPT-5 NanoOpenAI
Capability
Capabilities Index (ECI)140.0 (best)139.4
ECI rank#99 of 148 (best)#102 of 148
GPQA DiamondGraduate-level science questions75.8% (best)69.4%
FrontierMath Tiers 1–3Research-level mathematics—20.0%
OTIS Mock AIME 2024–2025Competition mathematics88.9% (best)81.1%
SimpleQA VerifiedShort factual questions—11.7%
Price per million tokens
Input$0.15$0.05 (best)
Output$0.60$0.40 (best)
Cached input—$0.005
Blended (3:1)$0.263$0.138 (best)
Long-context rateSame rateSame rate
Price sourceMedian of 36 providersOfficial OpenAI API
Limits
Context window131,072 tokens400,000 tokens (best)
Max output32,768 tokens128,000 tokens (best)
Inputs and features
TextYesYes
ImagesNoYes
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYesYesminimal · low · medium · high
Tool callingYesYes
Structured outputYesYes
Availability
WeightsOpenProprietary
API model ID—gpt-5-nano
API providers39 (best)21
ReleasedAug 5, 2025Aug 7, 2025
Knowledge cutoff—May 30, 2024
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 120B$2.70
  • GPT-5 Nano$1.30
04 — Questions

Which should you choose?

Which is better: GPT OSS 120B or GPT-5 Nano?

GPT-5 Nano is the better all-round choice, scoring 70/100 against GPT OSS 120B (61). It leads on price, inputs & features and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT OSS 120B or GPT-5 Nano?

GPT-5 Nano is cheaper at $0.05 input / $0.40 output per million tokens (official OpenAI API price). GPT OSS 120B costs $0.15 input / $0.60 output per million tokens (median across 36 API providers). At a typical mix of three input tokens to one output token, that is $0.138 per million tokens for GPT-5 Nano versus $0.263 for GPT OSS 120B (1.9× as much).

Which scores higher on benchmarks?

GPT OSS 120B scores higher on the Capabilities Index (ECI): GPT OSS 120B 140.0 (#99 of 148) and GPT-5 Nano 139.4 (#102 of 148). The confidence ranges of the top two overlap (135.3–142.3 vs 134.9–141.7), so treat the gap as small. On individual benchmarks: GPQA Diamond — GPT OSS 120B 75.8%, GPT-5 Nano 69.4%; OTIS Mock AIME 2024–2025 — GPT OSS 120B 88.9%, GPT-5 Nano 81.1%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT OSS 120B and GPT-5 Nano yet, so there is no like-for-like coding score. On overall capability, GPT OSS 120B 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?

GPT-5 Nano has the largest context window at 400,000 tokens, against 131,072 for GPT OSS 120B. Maximum output per response: GPT OSS 120B up to 32,768, GPT-5 Nano up to 128,000 tokens.

Which can read images, PDFs, audio or video?

GPT OSS 120B accepts text; GPT-5 Nano accepts text and images. GPT-5 Nano handles the widest range of inputs.

Are any of these open source?

GPT OSS 120B publishes its weights and can be self-hosted; GPT-5 Nano is proprietary.

Which is newer?

GPT-5 Nano is the newest, released Aug 7, 2025. GPT OSS 120B came out Aug 5, 2025. Knowledge cutoff: GPT-5 Nano May 30, 2024.

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 Oct 4, 2026.

05 — Keep comparing

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