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Head-to-head comparison

GPT-4o-mini vs GPT-5.5

GPT-4o-mini (OpenAI) and GPT-5.5 (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 22 September 2026

As of 22 September 2026, GPT-5.5 holds the stronger ModelCap Index position (#13 vs #138); GPT-4o-mini is 50× cheaper per output token ($0.60/1M vs $30.00/1M); and GPT-5.5 offers the longer context window (1M vs 128K tokens).

Which should you choose?

Choose GPT-4o-mini if…

  • API cost matters — $0.60/1M output tokens against $30.00/1M, about 50× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.15/1M against $5.00/1M.

Choose GPT-5.5 if…

  • you want the stronger overall ModelCap Index position — #13 against #138 (82.5 vs 40.0 points).
  • you need the longer context window — 1M tokens against 128K.
  • you want provider choice — 3 listed API providers against 2.
  • ARC-AGI-2 is your yardstick — 85.0% against 0.0%.
  • AA Humanity's Last Exam is your yardstick — 45.8% against 4.2%.
  • you want the more recently listed model — GPT-5.5 was listed 24 April 2026, GPT-4o-mini 18 July 2024.

GPT-4o-mini vs GPT-5.5: specs, pricing and context

Specification comparison of GPT-4o-mini and GPT-5.5
FieldGPT-4o-miniOpenAIGPT-5.5OpenAI
ModelCap Index position#138#13
Index score40.082.5
EvidenceMeasuredMeasured
Input price / 1M tokens$0.15$5.00
Output price / 1M tokens$0.60$30.00
Context window128K tokens1M tokens
Max output tokens16K128K
API providers listed23
Weight accessAPI onlyAPI only
Input modalitiesText, Image, FileFile, Image, Text
First listed18 July 202424 April 2026
PublisherOpenAIOpenAI

Evidence: publisher-corpus-prior over 208 held-out anchors (59%); 1 specialist-board observation at 2.1% support (41%); shrunk 24.8 up toward the measured corpus · 7 public benchmark observations across 7 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: GPT-4o-mini vs GPT-5.5

Public benchmark boards where GPT-4o-mini or GPT-5.5 has a published result
BoardGPT-4o-miniGPT-5.5Leads
Arena codingArena (LMArena)—15201514–1526HighOnly one result
LMArena AgentLMArena—5.0%4.1%–6.0%X-HighOnly one result
ARC-AGI-2ARC Prize Foundation0.0%85.0%X-HighGPT-5.5
ARC-AGI-3ARC Prize Foundation—0.4%HighOnly one result
AA Intelligence IndexArtificial Analysis—38.4intelligence-index:v4.3:xhighOnly one result
AA τ²-Bench TelecomArtificial Analysis—93.9%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="GPT-5.5 (xhigh)":reasoning=trueOnly one result
AA Humanity's Last ExamArtificial Analysis4.2%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-4o mini":reasoning=false45.8%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-5.5 (xhigh)":reasoning=trueGPT-5.5
Terminal-Bench 2.1 Terminus 2Terminal-Bench—78.0X-HighOnly one result
WildClawBench OpenClawWildClawBench—58.2Only one result

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-mini vs GPT-5.5: common questions

Is GPT-4o-mini better than GPT-5.5?

GPT-5.5 ranks higher on the ModelCap Index as of 22 September 2026: #13 against #138. 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 do not overlap, but the aggregate Index does not predict performance on every task; compare the relevant benchmark configurations before choosing.

Is GPT-4o-mini cheaper than GPT-5.5?

GPT-4o-mini is cheaper on output tokens: $0.60/1M against $30.00/1M. Input tokens are $0.15/1M for GPT-4o-mini and $5.00/1M for GPT-5.5. 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 $0.60 for GPT-4o-mini versus $25.00 for GPT-5.5. GPT-4o-mini costs 97.6% 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-mini or GPT-5.5?

GPT-5.5 has the larger context window: 1M tokens against 128K.

Which is better for coding, GPT-4o-mini or GPT-5.5?

The two models do not share a coding benchmark board on ModelCap yet, so no head-to-head coding score is published; the ModelCap Index position is the closest overall signal.

Are GPT-4o-mini and GPT-5.5 open-weight models?

GPT-4o-mini: API only. GPT-5.5: API only. 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-mini and GPT-5.5?

ModelCap currently lists 2 API providers for GPT-4o-mini and 3 for GPT-5.5, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this GPT-4o-mini vs GPT-5.5 comparison?

Every figure comes from the sealed ModelCap dataset published 22 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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