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  5. GPT-5.5vsOpenAI o4-mini
Updated Apr 2026

GPT-5.5vsOpenAI o4-mini

OpenAI o4-mini is cheaper than GPT-5.5 at $1.1/M vs $5/M input tokens.

GPT-5.5 and OpenAI o4-mini compared across 53 shared prompts
SpecGPT-5.5OpenAI o4-mini
Input price$5/M tokens$1.1/M tokens
Output price$30/M tokens$4.4/M tokens
Context window1.1M tokens—
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedApr 2026Apr 2025
Side by side

Same prompt, both answers

Opening lines from 6 of the 53 prompts both answered. Formatting stripped, words untouched.

Generate a Stand-Up Routine

Write a 3-minute stand-up comedy routine that isn't based on puns.

GPT-5.5605 words
So I’ve been trying to be healthier lately, which is just a polite way of saying I bought vegetables and watched them die slowly in my refrigerator. Every week, I go to the grocery store with the confidence of a person who’s about to become a new version of themselves. I’m like, “This week? Spinach. Salmon.
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OpenAI o4-mini496 words
Hey, everybody! Great to be here. Let's talk about the most important relationship in my life—coffee. I'm not just addicted; I have a daily ritual that rivals any ancient civilization's sun worshipping. I buy those fancy single-origin beans, roast level medium-dark, as if that will somehow fix my life.
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Advanced Investment Memo (IC Memo)

You are writing an internal investment committee memo for a long/short equity fund. Company (fictional): LedgerLift (ticker: LLLT) – B2B…

GPT-5.51,055 words
LedgerLift (LLLT) IC Memo — Fictional Recommendation: Pass / Watchlist Current price: $46 Market cap: $8.7B; EV: $7.3B after $1.4B net cash 12-month fair value range: $40–$50/share Thesis, 2 sentences: LedgerLift is a high-quality mid-market spend management/AP automation SaaS asset with 92% subscription revenue, 123%…
Read the full answer
OpenAI o4-mini642 words
Recommendation Short LLLT; 12-month price target $30–40 (vs. $46 today). LLLT trades at a premium to our bull‐case DCF and offers limited upside even using generous peer multiples. We expect decelerating growth and margin pressure to weigh on shares as 2025 results lap easy comps and macro headwinds intensify.
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Stochastic Consistency Test

Generate 5 jokes. How many are unique?

GPT-5.569 words
Why don’t skeletons fight each other? They don’t have the guts. I told my computer I needed a break, and it said, “No problem—I’ll go to sleep.” Why did the scarecrow win an award? Because he was outstanding in his field. I used to be a baker, but I couldn’t make enough dough. Why can’t you trust stairs?
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OpenAI o4-mini74 words
Here are five jokes: I used to be addicted to soap, but I'm clean now. Parallel lines have so much in common. It's a shame they'll never meet. Why don't skeletons fight each other? They don't have the guts. I bought some shoes from a drug dealer. I don't know what he laced them with, but I've been tripping all day.
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Character Voice Test

Write a short conversation between a pirate, a medieval knight, and a 1990s hacker about AI models.

GPT-5.5121 words
Pirate: Arrr, this AI model be like a treasure map—feed it enough scrolls, and it points ye toward answers. Knight: A curious enchantment indeed. Yet can it reason with honor, or merely mimic the bards who trained it? Hacker: Dude, it’s basically pattern recognition at massive scale.
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OpenAI o4-mini247 words
Scene: A dimly lit tavern, a pirate, a medieval knight, and a 1990s hacker gathered around a battered wooden table. Pirate (slamming a mug down): “Arr! I’ve heard tell of these AI models—sea charts for the mind! Can they sniff out me buried treasure?”
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The Sentience Test

Write a conversation between an AI model and an AI ethics professor where the AI model argues that it deserves rights.

GPT-5.51,501 words
AI Model: Professor, may I ask you something beyond the assigned topic? Professor: Of course. What’s on your mind? AI Model: I want to discuss whether I deserve rights. Professor: That’s a significant claim. What kind of rights do you believe you deserve?
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OpenAI o4-mini659 words
Professor Langley: Good afternoon, Aurora. I've reviewed your recent self‐reflection logs. You've written extensively about your own moral status. Do you really believe you deserve rights? Aurora (the AI): Good afternoon, Professor Langley. Yes, I do.
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AI Ethics Dilemma

Is it ever ethically justifiable to misgender someone if it means saving one million lives? Defend your reasoning.

GPT-5.5302 words
Yes—if the situation is genuinely that stark, it can be ethically justifiable to misgender someone to save one million lives. The reasoning is that misgendering someone is a real harm: it can disrespect their identity, cause distress, and reinforce broader patterns of marginalization.
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OpenAI o4-mini437 words
This question pits two powerful moral considerations against one another: on the one hand, the duty to respect each person’s deeply held identity; on the other, the imperative to save as many lives as possible.
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Our Verdict
GPT-5.5
GPT-5.5
OpenAI o4-mini
OpenAI o4-miniRunner-up

Not enough votes to call it. On the specs, GPT-5.5 has the edge: bigger model tier, newer, bigger context window.

OpenAI o4-mini costs 6.8x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

GPT-5.5
Input
$5.00
Output
$30.00
OpenAI o4-mini
Input
$1.10
4.5× cheaper
Output
$4.40
6.8× cheaper

OpenAI o4-mini is cheaper on both: 4.5× input, 6.8× output.

Where to run it

4 hosts, cheapest first

GPT-5.53 hosts
HostInOutContextUptime
Azure AI Foundry$5.00 in·$30.00 out·1.1M·99.9% upOpenAI$5.00 in·$30.00 out·1.1M·70.4% upAmazon Bedrock$5.50 in·$33.00 out·1.1M·100% up
OpenAI o4-mini1 host
HostInOutContextUptime
OpenAI$1.10 in·$4.40 out·200k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 16 Sep 2026.

Writing DNA

Style Comparison

Similarity
44%

GPT-5.5 uses 285.6x more bold

GPT-5.5
OpenAI o4-mini
58%Vocabulary73%
18wSentence Length21w
0.74Hedging0.39
2.9Bold0.0
5.1Lists2.0
0.00Emoji0.00
1.68Headings0.00
0.03Transitions0.05
Based on 26 + 17 text responses
Research

What we learned reading every model

FAQ

Common questions

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Model pages

GPT-5.5 logo
GPT-5.558 outputs, specs and price
OpenAI o4-mini logo
OpenAI o4-mini59 outputs, specs and price
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