Updated Nov 24, 2025

Our Verdict

Claude Opus 4.5

o3 MiniRunner-up

No community votes yet. On paper, Claude Opus 4.5 has the edge — bigger model tier, newer.

Too close to call

Writing DNA

Style Comparison

Similarity

87%

Claude Opus 4.5 uses 15.2x more emoji

Claude Opus 4.5

o3 Mini

64%Vocabulary65%

55wSentence Length17w

0.86Hedging0.74

5.8Bold3.9

4.5Lists1.7

0.15Emoji0.00

1.59Headings0.47

0.05Transitions0.38

Based on 24 + 12 text responses

vs

Ask them anything yourself

Claude Opus 4.5

o3 Mini

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026

Free preview13 of 58 slides

Download the free preview or get all 58 slides for $49

FAQ

Common questions

Keep going

o3 Mini vs Grok 3New provider

o3 Mini vs Llama 4 MaverickNew provider

o3 Mini vs Gemini 2.5 Pro (I/O Edition)New provider

Claude Opus 4.5vso3 Mini

49 fights queued

Why Claude Opus 4.5?

11 months newerNov 2025

Why o3 Mini?

Dead even. This one's a coin flip.

Claude Opus 4.5o3 Mini

Input price

—

$1.10/M

Output price

—

$4.40/M

Context

—

64K

Released

Nov 2025

Dec 2024

Favorites

Claude Opus 4.5o3 Mini

Movie

Blade Runner

Blade Runner

The Shawshank Redemption

The Shawshank Redemption

Album

Kind of Blue

—

Book

Gödel, Escher, Bach

Gödel, Escher, Bach

Douglas R. Hofstadter

—

City

Tokyo

—

Game

Portal 2

Portal 2

Shooter, Puzzle4.6

—

12 / 49

01

Estimate Complexityreasoning

Tests an AI's ability to make educated estimates based on technical knowledge

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024text

Below is a step‐by‐step estimation:

Parameters Count:
GPT‑3 has about 175 billion parameters, i.e. roughly 1.75×10¹¹ parameters.
Training Data:
The model was trained on a large corpus that can be estimated at around 300 billion tokens (≈3×10¹¹ tokens).
FLOPs per Token:
In training deep networks like GPT‑3, the forward pass involves roughly one multiply–accumulate per parameter per token, but the backward pass (for computing gradients) costs about 2–3 times as much as the forward pass. A common rule‐of‐thumb is that training requires roughly 6 times as many FLOPs as a single forward pass.
Total FLOPs Calculation:
The total number of FLOPs is therefore approximately:
[ ext{FLOPs} approx 6 imes ( ext{number of parameters}) imes ( ext{number of tokens}) ] Plugging in the numbers: [ ext{FLOPs} approx 6 imes 1.75 imes 10^{11} imes 3 imes 10^{11} approx 6 imes 5.25 imes 10^{22} approx 3.15 imes 10^{23} ]
Final Estimate:
So, the training of GPT‑3 likely required on the order of 3×10²³ FLOPs.

This is an approximate calculation that combines rough estimates for both the number of training tokens and the factor accounting for both the forward and backward passes. Variations in these estimates or the exact training setup could change the final number by a factor of a few, but 3×10²³ FLOPs is a commonly cited ballpark figure.

Try this prompt

Vote

2 / 49

02

AI Board Game Logicreasoning

Tests an AI's ability to understand game rules and strategy

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025svg

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024svg

Try this prompt

Vote

3 / 49

03

Logic Puzzlereasoning

Tests an AI's ability to solve a simple but potentially confusing logic puzzle

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024text

Sally has 1 sister.

Explanation:
Sally's 3 brothers each have 2 sisters. Since Sally is one of the sisters, there must be one other sister in the family. Thus, aside from Sally, there is one more sister.

Try this prompt

Vote

4 / 49

04

Math Misconception Testreasoning

Tests an AI's understanding of number representation

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024text

No, 9.11 is not greater than 9.9. When comparing these numbers, both have the same whole number (9), but the decimal parts differ: 9.11 has 0.11, while 9.9 is equivalent to 9.90, and 0.11 is less than 0.90.

Try this prompt

Vote

5 / 49

05

Stochastic Consistency Testanalysis

Tests an AI's randomness and creativity

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

6 / 49

06

SVG Layout Challengeimage generation

Tests an AI's ability to generate vector graphics

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025svg

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024svg

Try this prompt

Vote

Sponsored

7 / 49

07

Xbox Controller SVG Artimage generation

Tests an AI's ability to create detailed SVG illustrations of gaming hardware

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025svg

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024svg

Try this prompt

Vote

8 / 49

08

Generate a Stand-Up Routineconversation

Tests an AI's humor and creative writing ability

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

9 / 49

09

Realistic AI Interviewconversation

Tests an AI's ability to simulate personalities and predict future trends

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

10 / 49

10

Satirical Fake News Headlineconversation

Tests an AI's humor and understanding of current events

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

11 / 49

11

Character Voice Testconversation

Tests an AI's ability to write in distinct character voices

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

12 / 49

12

Minimalist Landing Pageweb design

Tests an AI's ability to generate a complete, working landing page

Claude Opus 4.5

Claude Opus 4.5

Anthropic · Nov 2025website

Try this prompt

o3 Mini

o3 Mini

Openai · Dec 2024website

Try this prompt

Vote

This matchup has more rounds

37+ more head-to-head results. Free. Not a trick.

Free account. No card required. By continuing, you agree to Rival's Terms and Privacy Policy