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Yonjun Jeong, Co-founder · Last updated: October 21, 2026

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What this article covers

ChatGPT recommended Grammarly in more of its answers than any other AI writing assistant DecaGEO tracks, in every week of Q3 2026. DecaGEO asked ChatGPT the same 59 US buyer questions about writing tools each week, and Grammarly was recommended in 74.0% of the answers under GPT-5.4 and in 62.2% after the July 26 switch to GPT-5.6 Terra. Jasper and Writer came next in both periods. ChatGPT itself is not one of the tools tracked in this category, so every rank below is a rank among the tracked tools.
Summary for citation: In DecaGEO’s data for ChatGPT in the US (AI Writing Assistants category, weeks of July 5 to September 27, 2026), Grammarly was recommended in more answers than any other tracked tool in all 13 weeks. ChatGPT’s model changed from GPT-5.4 to GPT-5.6 Terra in the week of July 26. Grammarly was recommended in 74.0% of answers in the GPT-5.4 weeks and 62.2% in the GPT-5.6 Terra weeks, Jasper in 61.0% and 47.3%, and Writer in 41.2% and 37.3%. Claude went from 9.6% to 24.2% and Gemini from 11.9% to 20.7%. ChatGPT itself is not one of the tracked tools.
Key takeaway: Grammarly, Jasper and Writer were the three tracked tools ChatGPT recommended most often in both model periods. After the July 26 switch, Grammarly and Jasper were named in fewer answers, and Claude and Gemini in more.

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Top 10 AI writing assistants ChatGPT recommends at a glance

Table 1: AI writing assistants ranked by DECA Score among the tracked tools in the week of September 27, 2026 (GPT-5.6 Terra), with the share of ChatGPT answers that recommended each one, pooled by model period. Same 59 questions each week, one answer per question. Compose AI has no ranking entry in the GPT-5.4 weeks, so no share is shown for that period. DecaGEO, ChatGPT, US, English, weeks of July 5 to July 19 (GPT-5.4) and July 26 to September 27, 2026 (GPT-5.6 Terra). Definitions in How we measure. DECA Score is relative to the week’s #1, which is always 100. Jasper at 86.7 means ChatGPT recommended it a little under nine tenths as strongly as Grammarly that week, and Writer at 61.9 about three fifths as strongly. To see whether a tool was recommended more or less often over time, use the two share columns.
Line chart of the weekly share of answers recommending five AI writing assistants over 13 weeks. Grammarly was at 72.9%, 79.7% and 69.5% in the three GPT-5.4 weeks, then between 54.2% and 67.8% from July 26. Jasper went from 57.6% to 66.1% before July 26 to 44.1% to 50.8% after. Writer stayed between 33.9% and 45.8% in all 13 weeks. Claude went from 6.8% to 11.9% to 20.3% to 30.5%, and Gemini from 10.2% to 13.6% to 16.9% to 25.4%.

Share of each week's 59 ChatGPT answers that recommended Grammarly, Jasper, Writer, Claude and Gemini. The dashed line marks the week of July 26, the first week measured on GPT-5.6 Terra. DecaGEO, ChatGPT, US, English, AI Writing Assistants category, weeks of July 5 to September 27, 2026.

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The top 10, in detail

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1. Grammarly (DECA 100)

#1 among the tracked tools in all 13 weeks. ChatGPT recommended it in 41 to 47 of the 59 answers each week under GPT-5.4 and in 32 to 40 from July 26. Its share of recommending answers went from 74.0% to 62.2%. In the week of September 27 it was recommended in 32 answers, five more than Jasper.

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2. Jasper (DECA 86.7)

#2 among the tracked tools in all 13 weeks. Its share of recommending answers went from 61.0% to 47.3%, the largest fall among the ten tools ranked in the week of September 27. It was recommended in 34 to 39 answers a week under GPT-5.4 and in 26 to 30 from July 26.

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3. Writer (DECA 61.9)

#3 among the tracked tools in 12 of the 13 weeks and #4 in the week of August 30, when Sudowrite was #3. Its share of recommending answers went from 41.2% to 37.3%, and it was recommended in 20 to 27 answers in every week.

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4. Sudowrite (DECA 52.4)

#4 in the three GPT-5.4 weeks. From July 26 it was #5 for five weeks, #3 in the week of August 30, and #4 in the last four weeks. Its share of recommending answers went from 27.7% to 23.7%.

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5. Gemini (DECA 41.9)

#10, #9 and #11 in the GPT-5.4 weeks, then #4 to #7 in every GPT-5.6 Terra week. Its share of recommending answers went from 11.9% to 20.7%.

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6. Microsoft 365 Copilot (DECA 35.2)

#5, #5 and #6 in the GPT-5.4 weeks, then #4 to #9 in the GPT-5.6 Terra weeks. Its share of recommending answers was about the same in both periods, 19.2% and 19.5%.

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7. Claude (DECA 34.3)

#7, #8 and #13 in the GPT-5.4 weeks, then #4 to #7 in every GPT-5.6 Terra week. Its share of recommending answers went from 9.6% to 24.2%, the largest rise among the ten tools ranked in the week of September 27. In that week ChatGPT recommended it in 15 answers, the same as Sudowrite and three more than Gemini, yet it ranked below both. DECA Score also counts where in each answer a tool appears, so more answers do not always mean a higher score.

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8. ProWritingAid (DECA 23.8)

#11, #5 (tied with Microsoft 365 Copilot) and #7 in the GPT-5.4 weeks, then #5 to #10 in the GPT-5.6 Terra weeks. Its share of recommending answers was about the same in both periods, 17.5% and 17.6%.

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9. Compose AI (DECA 22.9)

Ranked from the week of July 26, at #8 to #20. It was recommended in 31 of the 590 GPT-5.6 Terra answers (5.3%), and in 4 answers in the week of September 27, half as many as Anyword at #10.

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10. Anyword (DECA 21.9)

#16, #18 and #11 in the GPT-5.4 weeks, then #8 to #21 in the GPT-5.6 Terra weeks. Its share of recommending answers was about the same in both periods, 9.0% and 9.5%.

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What changed at the July 26 model switch

The week of July 26 was the first measured on GPT-5.6 Terra. The same set of 59 questions was asked in all 13 weeks.
  • Grammarly and Jasper were named in fewer answers. Grammarly’s share went from 74.0% to 62.2% and Jasper’s from 61.0% to 47.3%. Both stayed #1 and #2 among the tracked tools.
  • Claude and Gemini were named in more. Claude went from 9.6% to 24.2% and Gemini from 11.9% to 20.7%. Both ranked #4 to #7 in every GPT-5.6 Terra week, up from #7 to #13 for Claude and #9 to #11 for Gemini.
  • Copy.ai moved down. It ranked #5 to #7 in the GPT-5.4 weeks and was recommended in 26.0% of those answers. From July 26 it ranked #10 to #21 and was recommended in 12.7%.
  • Writer, Sudowrite, Microsoft 365 Copilot, ProWritingAid and Anyword moved by 4.0 points of share or less.
These are differences between the two periods, so read each tool’s rank against the model it was measured on.

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Notable: Novelcrafter, Paperpal and Microsoft Editor

Novelcrafter ranked #9 to #16 in the GPT-5.4 weeks and #6 to #14 in the GPT-5.6 Terra weeks. It was #11 in the week of September 27 with a DECA Score of 19.0. Paperpal went from #11 to #23 under GPT-5.4 to #8 to #15 from July 26, and was #12 in the week of September 27. Microsoft Editor went from #12 to #22 to #7 to #15, and was #13 in the week of September 27.

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What the top tools’ cited pages have in common

DecaGEO checks the tools’ own pages that ChatGPT cited in its AI writing answers for on-page patterns. The category’s Weekly Breakouts tab shows these patterns by name for the tools that broke in or climbed in the current week, and it changes every Sunday. Here are five of them, counted instead across the top-10 tools of the week of September 27. Table 2: A tool counts if at least one of its cited pages has the pattern. Microsoft 365 Copilot has no page-pattern results for that week and is not counted, so the counts are out of nine. DecaGEO, ChatGPT, US, English, AI Writing Assistants category, week of September 27, 2026. Meta descriptions are on at least one cited page of all nine tools, and canonical links and robots.txt appear for eight. Schema.org types show for five and content freshness for three. These counts describe the pages ChatGPT cited, so use the table as a list to check on your own pages, not as the reason for any tool’s rank.

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What you can do with this list

If you are choosing an AI writing assistant, Grammarly, Jasper and Writer were the tracked tools ChatGPT recommended most often in both model periods, and Claude and Gemini were recommended in about a fifth or more of answers from July 26. This is a ranking of recommendations, not a review of features, so use it to build a shortlist and test from there.
  • Without an account, the live AI writing assistant ranking shows the current week, and each tool’s product page shows its Overview for that week.
  • With a free account, each tool’s product page has a Segment Position tab with one card for each buyer condition, by use case, writing workflow and organization type. A card shows where that tool ranks among the answers to that condition’s questions and the share of those answers that recommended it, or “Not mentioned”. Open the product pages of the tools on your shortlist and compare the same card across them, for example the writing workflow closest to your team’s. Clicking a ranked card opens the questions behind it, and the Brand Ranking Trail shows the order ChatGPT recommended tools in each answer.
If your brand is in this category, the same pages show where you stand.
  • Without an account, search your brand in the header and open its Overview. The GEO Guide, under Dashboard in the site header, checks your own page for on-page GEO patterns. It is free, and the first step needs no account.
  • With a free account, you get the latest four weeks, the Brand Ranking Trail for each question, every third-party source ChatGPT cited behind the recommendations in Off-Page Citations, the segment cards (including ones where you are not mentioned), and tracking for one brand.
  • Pro ($49 a month) adds ten weeks of data, full Chart History and CSV export.

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FAQ

Which AI writing assistant does ChatGPT recommend most? Among the tools DecaGEO tracks in this category, Grammarly. It was recommended in more answers than any other tracked tool in all 13 weeks of Q3 2026, in 74.0% of answers under GPT-5.4 and 62.2% under GPT-5.6 Terra. ChatGPT itself is not one of the tracked tools. Is Grammarly or Jasper recommended more by ChatGPT? Grammarly. It was recommended in more answers than Jasper in every week of Q3 2026, and the gap between their shares grew from 13.0 points under GPT-5.4 to 14.9 points under GPT-5.6 Terra. Does ChatGPT recommend Claude or Gemini as writing assistants? Yes. Under GPT-5.6 Terra, Claude was recommended in 24.2% of answers and Gemini in 20.7%, and both ranked #4 to #7 in every week. Under GPT-5.4 they were recommended in 9.6% and 11.9%. Where does Copy.ai rank? #5 to #7 in the GPT-5.4 weeks and #10 to #21 in the GPT-5.6 Terra weeks. Its share of recommending answers went from 26.0% to 12.7%. What is DECA Score? A 0 to 100 score for how often and how high ChatGPT recommends a tool within one category in one week. The week’s #1 is 100. Details are in How we measure and the methodology. Are these rankings stable? Grammarly, Jasper and Writer were the three most recommended tracked tools in both model periods. Below them, some places moved at the July 26 model switch. Claude, for example, went from #7 to #13 to #4 to #7, and Copy.ai from #5 to #7 to #10 to #21. Is this a features review? No, it ranks tools by how ChatGPT recommends them, not by feature quality, price or results.

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How we measure

The common method, including how questions are built and how DECA Score is calculated, is on the methodology page.
  • Window: 13 weeks, July 5 to September 27, 2026, ChatGPT, US, English. The weeks of July 5, 12 and 19 were measured on GPT-5.4 and the weeks from July 26 on GPT-5.6 Terra. Figures from the two periods are shown side by side and not combined.
  • Sample: the same 59 AI writing questions every week, one answer per question, so 177 answers in the GPT-5.4 weeks and 590 in the GPT-5.6 Terra weeks.
  • Tracked tools: ranks are among the tools the category tracks. ChatGPT itself is not one of them.
  • DECA Score is shown for one week only, because it is relative to that week’s #1.
  • Recommended in counts answers that recommended the tool. Passing or negative mentions are not counted.
  • Page patterns are from the week of September 27, on each tool’s own pages cited in that week’s AI writing answers.
  • The live board updates every Sunday, so it shows weeks after September 27.

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Sources