ChatGPT vs Grok for writing

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.

Writing: GPT-6 Luna passed 5 of 5 and Grok 4.7 3 of 5. GPT-6 Luna answered 1.7× sooner at the median, 2.4 s against 4.0 s. GPT-6 Luna cost 42.3× less, $0.0005 against $0.0210 for the 5 replies. GPT-6 Luna's replies ran 11% longer, in tokens of reply, thinking not counted.

1. 1. Announce a second bakery shop on LinkedIn

   Everyday. GPT: 3 of 3 models passed, GPT-6 Luna the cheapest at $0.0001 · Grok: 0 of 1 model passed. The prompt in full.

   GPT-6 Luna passed this one and Grok 4.7 didn't. GPT-6 Luna answered sooner (2.9 s to 4.0 s), and GPT-6 Luna's reply cost less ($0.0001 to $0.0022); GPT-6 Luna wrote 149 tokens of reply, Grok 4.7 114.

   • GPT-6 Luna

     Passed: Graded 4.5 of 5 on average (lowest 4).

     We’re delighted to share that Crumb & Co. is opening a second shop in Leeds on 14 November!
     
     What began as one small bakery has grown thanks to the lovely people who’ve stopped by, shared a loaf, and made us feel part of the community. We’re excited to bring our freshly baked bread, pastries, and warm welcomes to a new neighbourhood.
     
     To celebrate opening day, we’ll be giving away free coffee. Pop in, say hello, and enjoy a cup with us—we’d love to meet you.
     
     Thank you to everyone who has supported Crumb & Co. so far. We can’t wait to open the doors and start this next chapter together. See you in Leeds on 14 November!

     389 tokens in, 149 out · 2.9 s · $0.0001 · 1 message on Pro · answered by openai/gpt-6-luna via OpenAI · September 27, 2026

   • Grok 4.7

     Failed: Graded 4.5 of 5 on average (lowest 4); but 94 words, under the 100 asked for.

     We're opening a second Crumb & Co. shop in Leeds on 14 November.
     
     The new bakery will offer the same bread, cakes and pastries you already know from our first shop, baked fresh each morning. If you've been asking for a Leeds location, this one is for you.
     
     On opening day, coffee is free with any purchase. Come in, say hello, and try something from the counter. We'd love to meet you and hear what you'd like to see on the shelves.
     
     Thank you for supporting a small bakery. We can't wait to welcome you.

     1,624 tokens in, 207 out (93 of them reasoning) · 4.0 s · $0.0022 · 1 message on Pro · answered by x-ai/grok-4.7 via xAI · September 27, 2026

2. 2. Rewrite corporate jargon in plain words

   Everyday. GPT: 2 of 3 models passed, GPT-6 Luna the cheapest at $0.0001 · Grok: 0 of 1 model passed. The prompt in full.

   GPT-6 Luna passed this one and Grok 4.7 didn't. GPT-6 Luna answered sooner (2.4 s to 19.3 s), and GPT-6 Luna's reply cost less ($0.0001 to $0.0088); GPT-6 Luna wrote 65 tokens of reply, Grok 4.7 60.

   • GPT-6 Luna

     Passed: Graded 4.7 of 5 on average (lowest 4).

     In Q3, teams across the company worked together to focus more on customers. Retention measures improved by 12%, and the rate of customer loss fell by 0.3 percentage points in the enterprise segment. The company also adjusted its customer contact channels to make better use of available capacity.

     417 tokens in, 124 out (59 of them reasoning) · 2.4 s · $0.0001 · 1 message on Pro · answered by openai/gpt-6-luna via OpenAI · September 27, 2026

   • Grok 4.7

     Failed: Graded 3.7 of 5 on average (lowest 3).

     In the third quarter, teams from different departments worked together on an initiative that put a stronger customer focus into practice. Retention measures rose 12%, and the speed at which enterprise customers left fell by 30 basis points. We also resized customer contact points across channels so they used available capacity more efficiently.

     1,657 tokens in, 1,631 out (1,571 of them reasoning) · 19.3 s · $0.0088 · 1 message on Pro · answered by x-ai/grok-4.7 via xAI · September 27, 2026

3. 3. Decline a meeting and offer two times

   Everyday. GPT: 3 of 3 models passed, GPT-6 Luna the cheapest at $0.0001 · Grok: 1 of 1 model passed, Grok 4.7 at $0.0019. The prompt in full.

   GPT-6 Luna and Grok 4.7 both passed this one. GPT-6 Luna answered sooner (1.3 s to 2.3 s), and GPT-6 Luna's reply cost less ($0.0001 to $0.0019); GPT-6 Luna wrote 64 tokens of reply, Grok 4.7 64.

   • GPT-6 Luna

     Passed: Graded 5.0 of 5 on average (lowest 5).

     Subject: Vendor Demo
     
     Hi Tom,
     
     Thanks for the invitation. I’m presenting to the board on Wednesday at 11:00, so I can’t make the demo then. Would Thursday at 10:00 or Friday at 14:00 work instead?
     
     Best,  
     [Your Name]

     395 tokens in, 64 out · 1.3 s · $0.0001 · 1 message on Pro · answered by openai/gpt-6-luna via OpenAI · September 27, 2026

   • Grok 4.7

     Passed: Graded 4.7 of 5 on average (lowest 4).

     Subject: Re: Vendor demo Wednesday
     
     Hi Tom,
     
     Thanks for the invitation. I can't make the vendor demo on Wednesday at 11:00 — I'll be presenting to the board then.
     
     I'm free Thursday at 10:00 or Friday at 14:00 if either works. Happy to join then.
     
     Best regards

     1,629 tokens in, 138 out (74 of them reasoning) · 2.3 s · $0.0019 · 1 message on Pro · answered by x-ai/grok-4.7 via xAI · September 27, 2026

4. 4. A product announcement with five rules

   Hard. GPT: 3 of 3 models passed, GPT-6 Luna the cheapest at $0.0001 · Grok: 1 of 1 model passed, Grok 4.7 at $0.0017. The prompt in full.

   GPT-6 Luna and Grok 4.7 both passed this one. GPT-6 Luna answered sooner (1.5 s to 2.6 s), and GPT-6 Luna's reply cost less ($0.0001 to $0.0017); GPT-6 Luna wrote 73 tokens of reply, Grok 4.7 53.

   • GPT-6 Luna

     Passed: Graded 4.0 of 5 on average (lowest 3).

     Meet the Nordvik 2, a desk lamp designed to bring flexible light to your workspace. Choose from five brightness levels, charge it via USB-C, and turn its arm up to 270 degrees to direct light where you need it. The Nordvik 2 costs €79 and ships on 1 December. Ready to brighten your desk?

     406 tokens in, 73 out · 1.5 s · $0.0001 · 1 message on Pro · answered by openai/gpt-6-luna via OpenAI · September 27, 2026

   • Grok 4.7

     Passed: Graded 4.0 of 5 on average (lowest 3).

     The Nordvik 2 desk lamp dims in five steps and charges from USB-C. Its arm turns 270 degrees, so you can aim the light where you need it. It costs €79 and ships on 1 December. Ready to light your desk?

     1,641 tokens in, 151 out (98 of them reasoning) · 2.6 s · $0.0017 · 1 message on Pro · answered by x-ai/grok-4.7 via xAI · September 27, 2026

5. 5. Argue both sides of free buses

   Hard. GPT: 3 of 3 models passed, GPT-6 Luna the cheapest at $0.0001 · Grok: 1 of 1 model passed, Grok 4.7 at $0.0065. The prompt in full.

   GPT-6 Luna and Grok 4.7 both passed this one. GPT-6 Luna answered sooner (2.5 s to 12.1 s), and GPT-6 Luna's reply cost less ($0.0001 to $0.0065); GPT-6 Luna wrote 186 tokens of reply, Grok 4.7 191.

   • GPT-6 Luna

     Passed: Graded 4.3 of 5 on average (lowest 4).

     Making buses free would give every resident reliable access to jobs, school, health care, and daily necessities, regardless of income. It would also speed boarding, reduce fare-enforcement costs, and encourage people to leave cars at home—easing congestion, pollution, and parking pressure. A city that treats public transit as essential infrastructure, rather than a service people must qualify to afford, can build a more connected and equitable community.
     
     But “free” buses still have to be paid for, and the bill could divert money from more urgent improvements: frequent service, safer stops, cleaner vehicles, and routes to underserved neighborhoods. If buses remain slow, crowded, or unreliable, removing fares may do little to persuade drivers to switch, while reducing funds that could make transit genuinely useful. Targeted fare assistance can protect riders who need it most without subsidizing every trip, including those by people who can readily afford to pay.

     384 tokens in, 186 out · 2.5 s · $0.0001 · 1 message on Pro · answered by openai/gpt-6-luna via OpenAI · September 27, 2026

   • Grok 4.7

     Passed: Graded 4.3 of 5 on average (lowest 4).

     Making buses free would remove the fare barrier that keeps low-income riders from jobs, clinics, and schools, and it would cut the cost and delay of collecting fares. More people would leave cars behind, easing congestion and pollution while filling seats that already run half empty. A city that treats transit as a public service, like streets or parks, can fund it through broad taxes and gain mobility, equity, and cleaner air in return.
     
     Free buses sound generous, but they shift a real cost onto taxpayers who may never ride, while inviting overcrowding, slower trips, and service that cannot keep up with demand. Without fares, agencies lose a direct signal of what routes people value and a revenue stream that pays drivers and buys buses. Cities that have tried fare-free service often face vandalism, disorder, and cuts elsewhere. Mobility is better served by targeted discounts for those who need them and reliable, frequent service that people will pay to use.

     1,618 tokens in, 1,159 out (968 of them reasoning) · 12.1 s · $0.0065 · 1 message on Pro · answered by x-ai/grok-4.7 via xAI · September 27, 2026

• GPT-6 Astra vs Grok 4.7: GPT-6 Astra 5 of 5, Grok 4.7 3; Grok 4.7 answered 1.2× sooner at the median and cost 2.6× less. GPT-6 Astra vs Grok 4.7, on every job.

• GPT-6 Sol vs Grok 4.7: GPT-6 Sol 4 of 5, Grok 4.7 3; GPT-6 Sol answered 1.2× sooner at the median and cost 1.9× less. GPT-6 Sol vs Grok 4.7, on every job.

• GPT-6 Luna vs Grok 4.7: GPT-6 Luna 5 of 5, Grok 4.7 3; GPT-6 Luna answered 1.7× sooner at the median and cost 42.3× less. GPT-6 Luna vs Grok 4.7, on every job.

Every GPT and Grok reply above was checked the same way as every other model's, by the rules published with the prompts: how the writing prompts are scored, and each one in full.

• The lineups

  GPT: 3 models, GPT-6 Astra, GPT-6 Sol, and GPT-6 Luna. Grok: one model, Grok 4.7.

• Price per message

  The least expensive GPT model is GPT-6 Luna (60 messages a day on Pro); Grok's one model is Grok 4.7 (250 messages a month on Pro).

• Context window

  GPT goes up to 1.05M tokens (GPT-6 Astra); Grok up to 500K tokens (Grok 4.7).

• Images and PDFs

  Every model here reads images. Every model here takes a PDF as a whole file.

• On the Free plan

  Free's one-time trial of 5 messages covers GPT-6 Sol, GPT-6 Luna, and Grok 4.7. Paid plans have every model, with messages every month.

In llmwise, a message to GPT goes to its maker, OpenAI, or through OpenRouter when llmwise can't reach the maker directly. Grok models are served only through OpenRouter, by endpoints that don't store or train on prompts. The Privacy Policy has the details.