Head-to-head comparison

GPT-4o (2024-08-06) vs GPT-5.5

GPT-4o (2024-08-06) (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 3 September 2026

As of 3 September 2026, GPT-5.5 holds the stronger ModelCap Index position (#9 vs #110); GPT-4o (2024-08-06) is 3× cheaper per output token ($10.00/1M vs $30.00/1M); and GPT-5.5 offers the longer context window (1M vs 128K tokens).

Which should you choose?

Choose GPT-4o (2024-08-06) if…

API cost matters — $10.00/1M output tokens against $30.00/1M, about 3× cheaper.
your workload is prompt-heavy — input tokens cost $2.50/1M against $5.00/1M.

Choose GPT-5.5 if…

you want the stronger overall ModelCap Index position — #9 against #110 (77.9 vs 24.2 points).
you need the longer context window — 1M tokens against 128K.
you want provider choice — 3 listed API providers against 2.
Arena coding is your yardstick — 1520 against 1360.
AA Intelligence Index is your yardstick — 56.3 against 9.4.
AA τ²-Bench Telecom is your yardstick — 93.9% against 28.9%.
AA Humanity's Last Exam is your yardstick — 45.8% against 2.3%.
you want the more recently listed model — GPT-5.5 was listed 24 April 2026, GPT-4o (2024-08-06) 6 August 2024.

GPT-4o (2024-08-06) vs GPT-5.5: specs, pricing and context

Specification comparison of GPT-4o (2024-08-06) and GPT-5.5
Field	GPT-4o (2024-08-06)OpenAI	GPT-5.5OpenAI
ModelCap Index position	#110	#9
Index score	24.2	77.9
Evidence	Measured	Measured
Input price / 1M tokens	$2.50	$5.00
Output price / 1M tokens	$10.00	$30.00
Context window	128K tokens	1M tokens
Max output tokens	16K	128K
API providers listed	2	3
Weight access	API only	API only
Input modalities	Text, Image, File	File, Image, Text
First listed	6 August 2024	24 April 2026
Publisher	OpenAI	OpenAI

Evidence: 3 public benchmark observations across 3 boards · 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 (2024-08-06) vs GPT-5.5

Public benchmark boards where GPT-4o (2024-08-06) or GPT-5.5 has a published result
Board	GPT-4o (2024-08-06)	GPT-5.5	Leads
Arena codingArena (LMArena)	13601352–1368	15201514–1526High	GPT-5.5
LMArena AgentLMArena	—	7.9%6.8%–9.0%X-High	Only one result
ARC-AGI-2ARC Prize Foundation	—	85.0%X-High	Only one result
ARC-AGI-3ARC Prize Foundation	—	0.4%High	Only one result
AA Intelligence IndexArtificial Analysis	9.4intelligence-index	56.3intelligence-index	GPT-5.5
AA Terminal-Bench 2.1Artificial Analysis	—	84.3%terminal-bench-2.1	Only one result
AA τ²-Bench TelecomArtificial Analysis	28.9%tau2-bench-telecom	93.9%tau2-bench-telecom	GPT-5.5
AA Humanity's Last ExamArtificial Analysis	2.3%humanitys-last-exam	45.8%humanitys-last-exam	GPT-5.5
WildClawBench OpenClawWildClawBench	—	58.2	Only 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 (2024-08-06) vs GPT-5.5: common questions

Is GPT-4o (2024-08-06) better than GPT-5.5?

GPT-5.5 ranks higher on the ModelCap Index as of 3 September 2026: #9 against #110. 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.

Is GPT-4o (2024-08-06) cheaper than GPT-5.5?

GPT-4o (2024-08-06) is cheaper on output tokens: $10.00/1M against $30.00/1M. Input tokens are $2.50/1M for GPT-4o (2024-08-06) and $5.00/1M for GPT-5.5. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, GPT-4o (2024-08-06) or GPT-5.5?

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

Which is better for coding, GPT-4o (2024-08-06) or GPT-5.5?

Arena coding: GPT-4o (2024-08-06) 1360, GPT-5.5 1520 — GPT-5.5 leads.

Are GPT-4o (2024-08-06) and GPT-5.5 open-weight models?

GPT-4o (2024-08-06): 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 (2024-08-06) and GPT-5.5?

ModelCap currently lists 2 API providers for GPT-4o (2024-08-06) 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 (2024-08-06) vs GPT-5.5 comparison?

Every figure comes from the sealed ModelCap dataset published 3 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.