Claude Haiku 4.5 · Writing
Claude Haiku 4.5 for writing: our test runs
Claude Haiku 4.5 ran our 5 writing prompts in llmwise, through the same pipeline your messages take. Here's every reply as it came, whether it passed, what it cost and what it counts as on Pro, next to the other models.
Based on 5 of our test runs on , through OpenRouter with the app's own prompt and settings.
Short answer
In our test runs on September 27, 2026, Claude Haiku 4.5 passed 4 of 5 of our writing prompts (1 of the 2 hard ones): tied 3rd of 15 models. Each reply counted as 1 message on Pro, where it has 250 a month, and cost $0.0011 to run on average.
Prompt by prompt
Each of the 5 writing prompts, and how Claude Haiku 4.5's reply did.
| Prompt | Result | Cost | Time |
|---|---|---|---|
| Announce a second bakery shop on LinkedInEveryday | Passed: Graded 4.0 of 5 on average (lowest 3). | $0.0013 | 2.6 s |
| Rewrite corporate jargon in plain wordsEveryday | Passed: Graded 4.3 of 5 on average (lowest 4). | $0.0008 | 1.6 s |
| Decline a meeting and offer two timesEveryday | Passed: Graded 5.0 of 5 on average (lowest 5). | $0.0010 | 2.0 s |
| A product announcement with five rulesHard | Failed: Graded 3.7 of 5 on average (lowest 3). | $0.0012 | 2.2 s |
| Argue both sides of free busesHard | Passed: Graded 4.0 of 5 on average (lowest 4). | $0.0014 | 3.4 s |
Every writing reply from Claude Haiku 4.5
Announce a second bakery shop on LinkedIn
An everyday prompt: “Announce a second bakery shop on LinkedIn”, in full.
Passed: Graded 4.0 of 5 on average (lowest 3).
We're thrilled to announce that Crumb & Co. is expanding! Our second shop opens in Leeds on 14 November. Since we started, you've supported us with every sourdough, pastry, and cup of coffee. This new location means more of you can enjoy fresh-baked goodness closer to home. To say thank you, we're offering complimentary coffee all day on opening day. Pop by, say hello, and see what we've built. Our Leeds team is ready to welcome you with the same warmth and quality that defines Crumb & Co. Same recipes, same care, same commitment to baking something special each morning. Here's to new beginnings—and more reasons to visit us. See you on 14 November.
420 tokens in, 169 out · 2.6 s · $0.0013 · 1 message on Pro · answered by anthropic/claude-haiku-4.5 via Amazon Bedrock ·
Rewrite corporate jargon in plain words
An everyday prompt: “Rewrite corporate jargon in plain words”, in full.
Passed: Graded 4.3 of 5 on average (lowest 4).
Here's a clearer version: Our Q3 initiative brought different departments together to focus on customer needs. The results were strong: we kept 12% more customers and reduced customer loss by 0.3 percentage points among large businesses. We also streamlined our customer contact channels to work more efficiently. (77 words)
462 tokens in, 73 out · 1.6 s · $0.0008 · 1 message on Pro · answered by anthropic/claude-haiku-4.5 via Amazon Bedrock ·
Decline a meeting and offer two times
An everyday prompt: “Decline a meeting and offer two times”, in full.
Passed: Graded 5.0 of 5 on average (lowest 5).
Subject: Re: Vendor Demo Invitation – Wednesday Hi Tom, Thanks for the invitation to the vendor demo on Wednesday at 11:00. Unfortunately, I have a board presentation scheduled at that time and won't be able to attend. I'm interested in seeing the demo though. Would either of these times work for you instead? - Thursday at 10:00 - Friday at 14:00 Let me know what suits your schedule best, and I'll get it on my calendar. Best regards
425 tokens in, 112 out · 2.0 s · $0.0010 · 1 message on Pro · answered by anthropic/claude-haiku-4.5 via Amazon Bedrock ·
A product announcement with five rules
A hard prompt: “A product announcement with five rules”, in full.
Failed: Graded 3.7 of 5 on average (lowest 3).
# Introducing the Nordvik 2 Desk Lamp Meet the Nordvik 2, designed for modern workspaces. This versatile lamp features a 270-degree rotating arm that positions light exactly where you need it. Five-step dimming lets you adjust brightness from soft ambient to focused task lighting. Charging is effortless with USB-C connectivity, keeping your desk cable-free and clutter-free. The minimalist design complements any interior while delivering reliable performance. At just €79, the Nordvik 2 offers exceptional value for professionals and students alike. Pre-order now for delivery on 1 December. Ready to upgrade your workspace with smarter lighting?
437 tokens in, 154 out · 2.2 s · $0.0012 · 1 message on Pro · answered by anthropic/claude-haiku-4.5 via Amazon Bedrock ·
Argue both sides of free buses
A hard prompt: “Argue both sides of free buses”, in full.
Passed: Graded 4.0 of 5 on average (lowest 4).
Free buses reduce traffic congestion and emissions while improving public health through increased mobility. They eliminate collection costs and fare evasion losses, funding themselves partly through reduced road maintenance. Equity improves dramatically—low-income residents gain economic mobility and job access. Cities like Luxembourg prove feasibility. The modest expense is offset by economic productivity gains, reduced healthcare costs, and environmental benefits that create long-term savings. However, free transit strains already limited budgets without guaranteed ridership increases to offset costs. Maintenance deteriorates as systems become overcrowded without capacity expansion funding. Cities risk losing accountability—free services often receive less operational scrutiny. Revenue vanishes precisely when transit needs modernization most. Targeted subsidies for low-income riders prove more efficient than universal free fares. Better solutions include congestion pricing for private vehicles and progressive fare structures, reserving resources for quality service rather than unsustainable giveaways.
414 tokens in, 195 out · 3.4 s · $0.0014 · 1 message on Pro · answered by anthropic/claude-haiku-4.5 via Amazon Bedrock ·
How it compares on writing
Claude Haiku 4.5 beside the job's picks among every model. 2 models share the hard-problems pick, and Claude Haiku 4.5 isn't one of them.
| Model | Passed | On Pro | Cost per reply |
|---|---|---|---|
| GLM 5.3Our pick: best value | 4 of 5 | 250 a month on Pro | $0.0006 |
| GPT-6 LunaOur pick: hard problems (shared), everyday | 5 of 5 | 60 a day on Pro | $0.0001 |
| Claude Haiku 4.5 | 4 of 5 | 250 a month on Pro | $0.0011 |
Every limit is published. Paid plans also have a monthly fair-use limit on AI cost: Pro $7.50, Max $20, Ultra $42, Studio $85. Using every message on your plan at typical sizes stays under it; very large messages and heavy research use it faster. Every limit, explained.
How these runs were done
Rubric (graded). The grader model scores the reply from 1 to 5 on each published criterion. It passes with an average of 4 or more and no criterion under 3, and only if it also meets the prompt's automatic rules (length, words it must or mustn't use).
The grader is Claude Opus 5.5 at low reasoning effort; its own replies are graded by GPT-6 Astra, so no model grades itself. Its prompt and every rubric are on the methods page.
Claude Haiku 4.5, and writing, elsewhere
- Claude Haiku 4.5: price, limits and messages on every plan
- The best AI for writing: our picks among every model
- Claude for writing
- Claude Haiku 4.5 for coding: our test runs
- Claude Haiku 4.5 for math: our test runs
- Claude Haiku 4.5 for data analysis: our test runs
- Rewrite for clarity: the prompt, and its price on each model
- Our test runs: 50 prompts on every model
Questions
Is Claude Haiku 4.5 good for writing?
In our test runs it passed 4 of 5 writing prompts, tied 3rd of the 15 models in llmwise. Every reply is on this page, so you can judge them yourself.
How many of my messages does a writing reply from Claude Haiku 4.5 use?
1 message each on Pro, where it has 250 a month on Pro. The price of a message is fixed and shown before you send it, however long the reply.
How were these runs done?
The same way for every model: each prompt sent through llmwise's own pipeline, each reply checked the same way. The methods page has every prompt and how each is scored.
Claude, GPT, Gemini, DeepSeek, Grok, Kimi, and GLM, in one chat.
See what a message costs before you send it. Free is 5 messages to try; sign in with an email link, no password or card.