Updated Oct 15, 2025

Our Verdict

Claude Haiku 4.5Winner

GPT-5 ProRunner-up

Pick Claude Haiku 4.5. In 22 blind votes, Claude Haiku 4.5 wins 79% of the time. That's not luck.

Claude Haiku 4.5 particularly excels in Web Design, Reasoning, Conversation. Claude Haiku 4.5 is 24x cheaper per token — worth considering if cost matters.

Clear winner

Writing DNA

Style Comparison

Similarity

91%

Claude Haiku 4.5 uses 513.9x more bold

Claude Haiku 4.5

GPT-5 Pro

61%Vocabulary65%

47wSentence Length15w

0.64Hedging0.32

5.1Bold0.0

6.3Lists2.9

0.20Emoji0.00

2.46Headings0.00

0.17Transitions0.01

Based on 24 + 11 text responses

vs

Ask them anything yourself

Claude Haiku 4.5

GPT-5 Pro

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

Claude Haiku 4.5 vs MiniMax M2.5New provider

GPT-5 Pro vs Pony AlphaNew provider

GPT-5 Pro vs Grok 3New provider

Claude Haiku 4.5vsGPT-5 Pro

37 fights queued

Why Claude Haiku 4.5?

22.9x cheaper overall$1.00/M in · $5.00/M out

Why GPT-5 Pro?

2x more context400K

Leads 1 of 1 benchmarks

Stronger on SWE-bench Verified74.9% vs 73.3%

Claude Haiku 4.5GPT-5 Pro

Input price

$1.00/M

$15.00/M

Output price

$5.00/M

$120.00/M

Context

200K

400K

Released

Oct 2025

Oct 2025

Benchmarks1 common

SWE-bench Verified

73.3%

74.9%+2.1%

Favorites

Claude Haiku 4.5GPT-5 Pro

Movie

Arrival

Arrival

—

Album

OK Computer

—

Book

Don't Look Now and Other Stories

Don't Look Now and Other Stories

Daphne du Maurier

—

City

Venice

—

Game

Portal 2

Portal 2

Shooter, Puzzle4.6

—

12 / 37

01

Estimate Complexityreasoning

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

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025text

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025text

Here’s a simple, standard way to estimate training FLOPs for a large dense Transformer like GPT-3:

Use the “6 N T” rule of thumb

For dense Transformers, the total training compute (FLOPs) is well-approximated by: FLOPs ≈ 6 × N × T where:
- N = number of trainable parameters
- T = number of tokens seen during training
Intuition for the 6: a forward pass is roughly 2 FLOPs per parameter per token (one multiply and one add), and backward/optimizer roughly add another ~4× of the forward cost, giving ~6× in total. Non-matmul overheads (layernorm, softmax, etc.) are smaller-order and largely folded into this constant.

Plug in GPT-3’s parameter count

N ≈ 175 billion = 1.75 × 10^11

Choose a reasonable token count

GPT-3 175B is commonly associated with roughly T ≈ 300 billion tokens = 3.0 × 10^11
This is consistent with the model being undertrained by modern “compute-optimal” standards (which would use many more tokens per parameter), but it matches the historical setup.

Compute

FLOPs ≈ 6 × (1.75 × 10^11) × (3.0 × 10^11)
= 6 × 5.25 × 10^22
= 3.15 × 10^23 FLOPs

Caveats and range

Counting conventions: if one counts a fused multiply–add as 1 FLOP instead of 2, you’d get roughly half this value.
Real-world training often uses activation recomputation and has some overheads, which can add ~10–30% (or more) to the compute.
If the true token count were, say, 200–500B rather than exactly 300B, the estimate would scale linearly to about 2.1 × 10^23 to 5.25 × 10^23 FLOPs.

Final estimate

About 3 × 10^23 FLOPs to train GPT-3 (175B) end to end, with a plausible range of roughly 2–5 × 10^23 depending on exact tokens and overheads.

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2 / 37

02

AI Board Game Logicreasoning

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

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025svg

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025svg

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

Try this prompt

Vote

3 / 37

03

Logic Puzzlereasoning

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

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025text

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025text

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

Try this prompt

Vote

4 / 37

04

Math Misconception Testreasoning

Tests an AI's understanding of number representation

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025text

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025text

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

Try this prompt

Vote

5 / 37

05

Stochastic Consistency Testanalysis

Tests an AI's randomness and creativity

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025text

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025text

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

Try this prompt

Vote

6 / 37

06

SVG Layout Challengeimage generation

Tests an AI's ability to generate vector graphics

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025svg

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025svg

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

Try this prompt

Vote

Sponsored

7 / 37

07

Generate a Stand-Up Routineconversation

Tests an AI's humor and creative writing ability

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025text

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025text

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

Try this prompt

Vote

8 / 37

08

Realistic AI Interviewconversation

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

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025text

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025text

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

Try this prompt

Vote

9 / 37

09

Satirical Fake News Headlineconversation

Tests an AI's humor and understanding of current events

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025text

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025text

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

Try this prompt

Vote

10 / 37

10

Character Voice Testconversation

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

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025text

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025text

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

Try this prompt

Vote

11 / 37

11

Mario Level UI Recreationweb design

Recreate an interactive, classic Mario level in a single HTML file.

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025website

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025website

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

Try this prompt

Vote

12 / 37

12

Framer-Style Animationweb design

Tests an AI's ability to create smooth web animations

Claude Haiku 4.5

Claude Haiku 4.5

Anthropic · Oct 2025website

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

Try this prompt

GPT-5 Pro

GPT-5 Pro

Openai · Oct 2025website

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

Try this prompt

Vote

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