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Head-to-head comparison

GPT-4o (2024-08-06) vs gpt-oss-20b

GPT-4o (2024-08-06) (OpenAI) and gpt-oss-20b (OpenAI) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 9 September 2026

As of 9 September 2026, GPT-4o (2024-08-06) holds the stronger ModelCap Index position (#132 vs #135); gpt-oss-20b is 76.9× cheaper per output token ($0.13/1M vs $10.00/1M); gpt-oss-20b offers the longer context window (131K vs 128K tokens); and gpt-oss-20b ships open weights.

Which should you choose?

Choose GPT-4o (2024-08-06) if…

  • you want the stronger overall ModelCap Index position — #132 against #135 (30.1 vs 27.9 points).

Choose gpt-oss-20b if…

  • API cost matters — $0.13/1M output tokens against $10.00/1M, about 76.9× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.03/1M against $2.50/1M.
  • you need the longer context window — 131K tokens against 128K.
  • you want to self-host: gpt-oss-20b ships open weights while GPT-4o (2024-08-06) is api only.
  • you want provider choice — 12 listed API providers against 2.
  • Arena coding is your yardstick — 1369 against 1360.
  • AA τ²-Bench Telecom is your yardstick — 60.2% against 28.9%.
  • AA Humanity's Last Exam is your yardstick — 11.0% against 2.3%.
  • you want the more recently listed model — gpt-oss-20b was listed 5 August 2025, GPT-4o (2024-08-06) 6 August 2024.

GPT-4o (2024-08-06) vs gpt-oss-20b: specs, pricing and context

Specification comparison of GPT-4o (2024-08-06) and gpt-oss-20b
FieldGPT-4o (2024-08-06)OpenAIgpt-oss-20bOpenAI
ModelCap Index position#132#135
Index score30.127.9
EvidenceMeasuredMeasured
Input price / 1M tokens$2.50$0.03
Output price / 1M tokens$10.00$0.13
Context window128K tokens131K tokens
Max output tokens16K118K
API providers listed212
Weight accessAPI onlyOpen weights
Input modalitiesText, Image, FileText
First listed6 August 20245 August 2025
PublisherOpenAIOpenAI

Evidence: 2 public benchmark observations across 2 boards · 3 public benchmark observations across 3 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: GPT-4o (2024-08-06) vs gpt-oss-20b

Public benchmark boards where GPT-4o (2024-08-06) or gpt-oss-20b has a published result
BoardGPT-4o (2024-08-06)gpt-oss-20bLeads
Arena codingArena (LMArena)13601352–136813691356–1382gpt-oss-20b
AA Intelligence IndexArtificial Analysis—9.0intelligence-index:v4.3:highOnly one result
AA Terminal-Bench 2.1Artificial Analysis—13.9%terminal-bench:2.1:terminus-2:e2b:pass-at-1:3-repeats:source-model="gpt-oss-20b (high)":reasoning=trueOnly one result
AA τ²-Bench TelecomArtificial Analysis28.9%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="GPT-4o (Aug)":reasoning=false60.2%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="gpt-oss-20b (high)":reasoning=truegpt-oss-20b
AA Humanity's Last ExamArtificial Analysis2.3%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-4o (Aug)":reasoning=false11.0%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="gpt-oss-20b (high)":reasoning=truegpt-oss-20b

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

GPT-4o (2024-08-06) vs gpt-oss-20b: common questions

Is GPT-4o (2024-08-06) better than gpt-oss-20b?

GPT-4o (2024-08-06) ranks higher on the ModelCap Index as of 9 September 2026: #132 against #135. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.

Is GPT-4o (2024-08-06) cheaper than gpt-oss-20b?

gpt-oss-20b is cheaper on output tokens: $0.13/1M against $10.00/1M. Input tokens are $2.50/1M for GPT-4o (2024-08-06) and $0.03/1M for gpt-oss-20b. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $10.00 for GPT-4o (2024-08-06) versus $0.13 for gpt-oss-20b. gpt-oss-20b costs 98.8% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.

Which has the bigger context window, GPT-4o (2024-08-06) or gpt-oss-20b?

gpt-oss-20b has the larger context window: 131K tokens against 128K.

Which is better for coding, GPT-4o (2024-08-06) or gpt-oss-20b?

Arena coding: GPT-4o (2024-08-06) 1360, gpt-oss-20b 1369 — gpt-oss-20b leads.

Are GPT-4o (2024-08-06) and gpt-oss-20b open-weight models?

GPT-4o (2024-08-06): API only. gpt-oss-20b: Open weights. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run GPT-4o (2024-08-06) and gpt-oss-20b?

ModelCap currently lists 2 API providers for GPT-4o (2024-08-06) and 12 for gpt-oss-20b, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this GPT-4o (2024-08-06) vs gpt-oss-20b comparison?

Every figure comes from the sealed ModelCap dataset published 9 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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