Julius AI vs ChatGPT for Data Analysis: Which Should You Use?

Last updated: October 2026.

You have a spreadsheet: sales by month, survey answers, a membership list with 40,000 rows. You want to know what is in it, and you would rather not spend a weekend on pivot tables. Two names keep coming up: ChatGPT, which you probably already use, and Julius AI, a tool built specifically for analysing data.

Both will read your file, write code, run it and hand you charts. The differences are in the details that matter once you rely on them: how big a file they will take, whether they can connect to where your data actually lives, what happens to your file after you upload it, and how easy it is to check the answer. This guide compares them on exactly those points, using each company’s own pricing, help and privacy pages as checked in October 2026.

Contents

Julius AI vs ChatGPT at a glance

	Julius AI	ChatGPT
Built for	Data analysis only	Everything, with data analysis built in
Runs code on your file	Yes, Python or R, code visible	Yes, Python, code visible
Spreadsheet size	No official cap; limited by memory (16 GB Plus, 32 GB Pro)	About 50 MB per spreadsheet
Database connections	Postgres, MySQL, SQL Server, Snowflake, BigQuery and more	None built in; cloud files from Google Drive, OneDrive, SharePoint
Trains on your data	No, on any plan	Yes by default on Free, Plus and Pro (you can switch it off)
Free plan	25 credits a day, lighter models	Yes, “limited” data analysis, 3 uploads a day
Paid from	$20/month (Plus)	$8/month (Go), $20/month (Plus)

What each tool actually does with your spreadsheet

Both tools work the same basic way, and it is worth understanding because it explains why they are far more reliable than asking a chatbot to “look at” your numbers. When you upload a file and ask a question, the AI writes a short program, runs it on a computer in the cloud, and reports what the program found. The arithmetic is done by the code, not by the language model guessing.

Julius AI

Julius writes Python or R and runs it in what it calls a secure cloud container, installing whatever libraries it needs. Each step can be expanded so you can read and copy the code and see its raw output, according to Julius’s own documentation.

• Files it reads: CSV, Excel (XLSX and XLS, including workbooks with several tabs you can refer to by name), JSON, Parquet, SQLite, SPSS .sav files, plus PDFs, images and code files.
• Charts: interactive bar, line and scatter charts you can hover over, or static charts in the usual Python styles. It can also build dashboards, reports and slides that export to PowerPoint, PDF and Google Slides.
• Statistics: because it runs real Python and R, it can do regressions, t-tests, ANOVA and the like. Julius’s own FAQ uses “Run a one-way ANOVA” as an example prompt, but it does not publish a list of supported tests, so treat this as general ability rather than a guaranteed feature list.

The SPSS support is a quiet advantage if you work with survey data from a university or research agency. ChatGPT’s help pages list only XLSX, XLS, CSV and TSV as spreadsheet formats.

ChatGPT

ChatGPT’s data analysis feature (once called Code Interpreter, then Advanced Data Analysis) writes and runs Python in what OpenAI’s help article describes as a “stateful Jupyter notebook environment”. Tables can display interactively, and bar, line, pie and scatter charts can be switched to interactive versions; other charts come back as images.

Two limits are worth knowing. The Python environment cannot reach the internet, so it cannot pull in live data. And OpenAI itself warns that very large or formula-heavy workbooks may not be fully analysed, and that values in scanned tables may not be read reliably. If your spreadsheet relies on formulas, ChatGPT sees the calculated values, not your logic.

The honest verdict: for a typical “what’s driving our sales?” question on a clean spreadsheet, both produce similar answers. Julius is noticeably more geared towards finished outputs such as dashboards and slide exports, while ChatGPT is stronger at the conversation around the data, such as explaining a method or drafting the email that goes with the chart.

File size and row limits

This is where the two differ most clearly.

• ChatGPT: the file uploads help page gives a limit of about 50 MB for CSV and spreadsheet files, depending on how wide each row is (other documents can be up to 512 MB). You can upload 80 files every three hours on paid plans; free users get three uploads a day.
• Julius: its FAQ says it does not enforce a row or file-size limit. The practical ceiling is the memory of the computer running your analysis, which the pricing page lists as 16 GB on Plus and 32 GB on Pro. We could not find an official limit on the number of files per chat.

For most office spreadsheets, 50 MB is plenty: that is typically several hundred thousand rows. If you work with exports from a CRM, web analytics or a national statistics office that run into millions of rows, Julius is the safer choice.

Connecting to your data

Uploading a file is fine for a one-off question. If your data lives in a database or gets updated every week, you want the tool to connect to it directly.

Julius has built-in data connectors for PostgreSQL, MySQL, SQL Server, Snowflake, BigQuery, Supabase, Google Ads and Meta Ads, as well as Google Drive, OneDrive and SharePoint. Google Sheets works by pasting a share link set to “Anyone with the link can view”, which is worth thinking about before you do it with sensitive data. Julius’s own pages are not fully consistent about which connector needs which plan, so expect database connections to need a paid plan and confirm on the pricing page before you subscribe.

ChatGPT lets you attach files from Google Drive, OneDrive and SharePoint, and its connected apps cover tools like Slack, Notion and Box. We found no built-in way to connect ChatGPT directly to a database such as Postgres or Snowflake. Business plans can build custom connections to internal tools, but that is a job for your IT team, not a setting you switch on.

Saving and reusing your work

Many comparisons online say Julius has “notebooks” and “projects”. Its current documentation does not describe either, and its Custom Agents feature has been discontinued. What it offers now is custom instructions, reusable “skill” files that Julius can write for you, shared workspaces for teams and scheduled runs (three on Pro, unlimited on Business), which are handy for a report that should refresh every Monday.

The catch is file storage. According to Julius’s documentation, files uploaded on the free plan are deleted after one hour of inactivity, and files on paid plans after seven days of inactivity. Permanent storage is listed only for Enterprise. That is good for privacy, but it means you should keep your own copy of the data and save the code for anything you will need again.

ChatGPT has Projects on every plan, which group chats and files around one piece of work: up to 5 files on Free, 25 on Go and Plus, and 40 on Pro and business plans. Project files stay until you delete them. It also has memory and scheduled tasks, but note one gap from OpenAI’s help pages: a scheduled task created inside a project cannot use that project’s uploaded files, so automated spreadsheet reports are not really ChatGPT’s strength yet.

Privacy: what happens to your file

This is the section most people skip and should not. The two companies take different default positions.

Julius AI

Julius’s security page answers the training question with one word: “Never.” It says your data is not used to train any models and that its AI providers are contractually barred from doing so. Bear in mind that Julius is a layer on top of other companies’ AI: its privacy policy names Anthropic, Google and OpenAI among the providers your information may be shared with in order to process it. Julius says it holds SOC 2 Type II certification, and that all data is stored and processed in the United States, which matters if you are bound by UK or EU data rules. You can ask for your information to be deleted when you cancel, and Julius says it will do so within seven business days.

ChatGPT

On the Free, Plus and Pro plans, OpenAI may use your conversations, including uploaded content, to train its models unless you turn off Settings › Data controls › Improve the model for everyone. The help article does not mention the newer Go plan by name; we would assume it follows the same rule but could not confirm it. Two details catch people out: giving a thumbs up or down on an answer can still send that whole conversation for training even after you opt out, and Temporary Chats are not used for training but may be kept for up to 30 days.

The Business, Enterprise and Edu plans do not train on your data by default, according to OpenAI’s enterprise privacy page. If your employer has one of those, use it for work files.

One more piece of background: during the New York Times copyright case, OpenAI was ordered to keep consumer chats it would normally delete. OpenAI says that obligation ended on 26 September 2025 and it returned to deleting chats within 30 days, while still holding a limited set of data from April to September 2025 under legal hold. We found no newer official update.

Accuracy: how to check AI analysis

Both companies are clear that the answers can be wrong. OpenAI’s terms say output “may not always be accurate”, and Julius’s terms make no promise about the accuracy of its output either. Research backs this up: academic studies of AI models working with spreadsheets and financial tables keep finding misread or invented numbers. Our guide to what ChatGPT can and can’t do for data analysis goes into the failure modes in more detail.

The good news is that because both tools show their code, you can check them without being a programmer. Five habits catch most mistakes:

1. Ask it to describe the data first. “How many rows and columns? What are the column types? How many blanks?” If it says 9,800 rows and you know there are 10,000, stop there.
2. Check one number by hand. Pick a total or average and recalculate it in Excel or Google Sheets. If it matches, the rest is far more likely to be right.
3. Read the cleaning steps. Look in the code for lines that drop rows, fill in blanks or remove “outliers”. Silent filtering is the most common cause of a confident wrong answer.
4. Ask what assumptions a statistical test makes and whether your data meets them. Both tools will tell you, if asked.
5. Check the chart axes. AI-made charts sometimes start the y-axis above zero or mix up labels. Our list of chart mistakes that mislead is a good checklist.

Pricing as of October 2026

Prices below are in US dollars from julius.ai/pricing and chatgpt.com/pricing. ChatGPT shows different prices in some countries, and VAT may be added.

Plan	Julius AI	ChatGPT
Free	$0: 25 welcome credits plus 25 a day, lighter models	$0: limited data analysis, 3 uploads a day
Entry	Plus: $20/month ($16 billed yearly), 2,000 credits a month plus daily top-ups	Go: $8/month (may include ads)
Standard	Pro: $45/month ($37 billed yearly), 5,000 credits a month	Plus: $20/month
Power user	Higher tiers listed in Julius’s docs	Pro: from $100/month
Teams	Business: $450/month ($375 billed yearly), up to 50 people	Business: $25 per user/month ($20 billed yearly), minimum 2 users
Enterprise	Contact sales	Contact sales

A note on Julius’s credits: Julius now charges credits per action rather than a fixed number of messages, so reviews that quote message limits are out of date. Running code and choosing stronger models use more credits, unused credits do not roll over, and you cannot currently buy top-ups. Julius’s pricing page and its credits documentation also disagreed on some figures when we checked, so look at the pricing page on the day you sign up.

On value, ChatGPT Plus wins for most people: the same $20 buys a capable data analyst and a general assistant. Julius Plus costs the same but only does data, so it earns its place when data is your daily work.

Which should you choose?

• Choose ChatGPT if you analyse a spreadsheet occasionally, your files are under 50 MB, and you want one subscription for everything. Turn off model training in Data controls before you upload anything work-related.
• Choose Julius AI if analysis is a core part of your job, you need to connect to a database, your files are very large, you work with SPSS survey files, or you want scheduled reports and slide exports without extra steps.
• Choose neither (for now) if your data includes personal or confidential information and your organisation has not approved an AI tool. Ask first; a data protection problem costs far more than the time saved.
• Just learning? Try both free plans on the same public dataset and compare. Our list of free datasets to practise with has plenty of options.

Frequently asked questions

Is Julius AI better than ChatGPT for data analysis?

For heavy, regular data work, yes: it handles larger files, connects to databases, schedules reports and does not train on your data. For occasional spreadsheet questions, ChatGPT does the analysis about as well and does much more besides, so it is better value.

Does Julius AI use ChatGPT?

Partly. Julius runs its own models and, on paid plans, lets you choose third-party models from companies including OpenAI and Anthropic. Its privacy policy names Anthropic, Google and OpenAI as providers your data may be shared with for processing, under contracts that bar them from training on it.

Can ChatGPT analyse an Excel file?

Yes. Upload an XLSX, XLS, CSV or TSV file of up to about 50 MB and ask questions in plain English. It writes and runs Python to answer. It sees calculated values rather than your formulas, and OpenAI warns that very large or formula-heavy workbooks may not be fully analysed.

Is it safe to upload company data to Julius AI or ChatGPT?

Only if your organisation allows it. Julius says it never trains on your data and holds SOC 2 Type II certification; ChatGPT’s business plans also exclude training by default. On personal ChatGPT plans, switch off “Improve the model for everyone” first, and remove personal details from the file either way.

Is there a free version of Julius AI?

Yes. As of October 2026 the free plan gives 25 welcome credits plus 25 credits a day, uses Julius’s lighter models and deletes uploaded files after an hour of inactivity. It is enough to try a few analyses, not for regular work.

Can AI replace learning Excel or statistics?

Not yet. You still need enough understanding to spot a wrong answer, which is why a little data literacy makes these tools far more useful and far less risky.

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