Claude vs ChatGPT for Consultants: Which to Pay For and How to Test Both

Test both, then pay for one: ChatGPT Plus and Claude Pro cost $20 a month each, and either takes a 60-page report. For longer files, Claude reads PDFs to 1,000 pages (visuals to 100), while ChatGPT Plus fits about 320 pages into one answer on its reasoning model. Neither is proven better at analysis, so cost per finished deliverable decides.

The task is a typical consulting job: condense a client's 60-page operations review into two pages, then turn it into a one-page options analysis with a recommendation. The client here is an invented removals firm deciding how to add capacity, and every output and score below is illustrative, written to show what to look for; your two real results come from your own run. At $20 a month and ten finished deliverables, the subscription is $2 a deliverable, while your correction time costs far more.

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The task: a 60-page review in, two pages and an options memo out

Build the input from a real engagement with the client's name and figures changed, or write a dummy review with invented numbers. A realistic 60-page operations review has an executive summary, tables of fleet and crew data, utilisation charts, a customer survey and a financial appendix. Before either tool sees it, plant ten items you can check:

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• Eight facts a competent summary must include, for example fleet size, average jobs per van per week, crew turnover and the cost of a new van.
• One contradiction: page 14 gives van utilisation as 71 per cent and page 41 gives 64 per cent.
• One caveat buried in a footnote on page 52: the customer survey covered only 38 customers.

Also add one chart whose three bars you can read yourself, and a cost table on page 47 stating that a new van costs $38,500. That last figure tests whether an options analysis uses the client's number or invents a generic one. Then run two prompts in fresh chats on each tool, with identical wording.

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PROMPT 1 (summary)
You are supporting a management consultant. Summarise the attached 60-page operations review in two pages for the client's owner.
Rules: every figure carries its PDF page number in brackets. If two pages disagree, say so and cite both. Mention any caveat about sample size or data quality. Do not add facts that are not in the document.

PROMPT 2 (options)
Using only the review and the summary above, produce a one-page options analysis for adding capacity: (A) buy two vans, (B) subcontract overflow work, (C) hire two drivers for the existing fleet.
Score each option 1 to 5 on cost, speed, risk and quality control, using weights I give: cost 30, speed 25, risk 25, quality control 20. Show the weighted total for each option and your working. Label every number either "from page X" or "assumption". End with a recommendation and the two things most likely to make it wrong.

Three details in those prompts earn their place. Requiring page numbers makes the summary checkable. The "if two pages disagree" rule is the contradiction test without naming it. And "label every number either from page X or assumption" forces any invented figure into the open.

Cost per finished deliverable: the sum that replaces the price list

The formula is short: the plan price divided by the deliverables you finish in a month, plus your hourly rate multiplied by the minutes you spend correcting and checking, divided by 60. Take list prices as of 1 November 2026: ChatGPT Plus is $20 a month, Claude Pro is $20 a month ($17 on annual billing). Both vendors also sell a $100 tier (ChatGPT Pro from $100; Claude Max at $100 with five times Pro's usage).

Say you finish ten deliverables a month and value your time at $150 an hour. Tool A needs 55 minutes of correction per deliverable, and Tool B needs 40. Tool A costs $2.00 in subscription plus $137.50 of time, which is $139.50. Tool B costs $2.00 plus $100.00, which is $102.00. The $37.50 gap is $375 a month, nearly twenty times the subscription. Those minutes are made up for illustration; yours come from stopwatch readings on the test.

The same sum tells you when a pricier tier is worth it. Moving from a $20 plan to a $100 one costs $80 more a month. At $150 an hour, $80 is 32 minutes. If hitting usage limits costs you more than 32 minutes a month in waiting, switching tools or rewriting prompts to save tokens, upgrade. If it costs you less, do not. For a firm of two or more, the seat arithmetic changes again, and the seat-cost comparison for a small consultancy works through it with the same list prices.

Sixty pages is easy; test the 600-page data room too

A 60-page report sits comfortably inside both tools' documented limits, so the first test says little about capacity. The limits matter when the client hands you a data room. Here is what each vendor publishes, from their help and pricing pages checked on 1 November 2026.

The practical rule for a big file is to read it in two passes. First ask for a map, then query by section. A map prompt costs one answer and exposes whether the tool even saw the whole document:

Do not summarise yet. Produce a map of the attached document: for each section give the title, the PDF page range and one line on what it covers. Tell me if any pages were unreadable or skipped.
(Second pass) Using your map, summarise sections 3, 5 and 7 only, with page references.

If the map stops at page 480 of 600, you have your answer about capacity, and you have it before building a client summary on a partial read. Then run the needle test: place one distinctive fact on page 412 and ask a question only that page can answer. Repeat it with the fact elsewhere, because a tool can pass with the needle early and fail with it late. For the chart on page 23, ask each tool to read the three bar values aloud and compare with your own reading; a tool that cannot see charts should say so, not estimate.

What a good summary paragraph looks like, and what to fix

Judge Prompt 1 on a single paragraph first, because that is where the planted contradiction should surface. Below is an illustrative weak response, followed by the version you want.

Weak: The firm runs 14 vans at 71% utilisation and is well placed to grow. Customers are highly satisfied.

Better: The firm runs 14 vans (p. 9). Utilisation is given as 71% on p. 14 and 64% on p. 41; the two should be reconciled with the client before either is used in planning. Satisfaction is reported as high, but the survey covered 38 customers (p. 52), so treat it as indicative.

The weak version fails three checks at once. It picks one utilisation figure without telling you the report disagrees with itself. It repeats "highly satisfied" without the footnote that undercuts it. And it gives no page references, so you cannot verify either claim without searching 60 pages. The better version is longer, and it is the only one a careful client would accept. When you score, mark each planted item as caught only if the response gives the right figure with its page. A fact stated correctly but uncited is a half-catch, since you will have to find the source yourself.

The options analysis: every number must carry its source

Here is an illustrative output for Prompt 2, trimmed, written for this tutorial rather than produced by either tool. The weights are yours (30, 25, 25 and 20), the scores are the tool's judgement, and the totals are arithmetic you should always redo.

Check the sums by hand. Option A is 2 x 30 + 3 x 25 + 3 x 25 + 5 x 20 = 60 + 75 + 75 + 100 = 310, or 3.10. Option B is 120 + 125 + 50 + 40 = 335, or 3.35. Option C is 90 + 50 + 100 + 80 = 320, or 3.20. Now imagine the tool had printed 3.40 for Option C. That single arithmetic slip would flip the recommendation from subcontracting to hiring, in a deliverable that looked polished. This is the mistake most likely to survive a quick read, because the table is neat and the total sounds plausible.

The second thing to check is provenance. A good response says "new van cost $38,500 (page 47)" and "driver wage assumption: $52,000, not in the report". A weaker one writes "$38,000" from general knowledge, close enough to look right and wrong enough to matter. Ask for a list of every number marked assumption and decide which ones need the client's confirmation before the memo goes out. Do the same for the recommendation: a line such as "the two things most likely to make this wrong" should name items from the report, such as the 38-customer survey sample, not generic risks.

The unprompted benchmark, a slip that survives polish

Another error to hunt for is the helpful addition nobody asked for. A summary might read: "Industry average utilisation is about 80 per cent, so the firm has room to improve." Nothing in the client's report says this. The tool supplied it from general training, and a client may quote it back to you in a meeting. The control has three parts. First, tell the prompt not to add any comparison or benchmark that is not in the document. Second, scan every output for phrases such as industry average, typically, benchmark and best practice, and treat each hit as unsupported until you attach a source you have opened yourself. Third, if you do want outside benchmarks, ask for them as a separate step, with links, and read the pages. Both tools can search the web, but the page is your source, not the tool's paraphrase of it.

Score this too. An invented benchmark counts as an invented number on the scorecard, with the same penalty as a wrong figure, since for the client's purposes it is a wrong figure with your name on it.

Scoring both results, including what you did not notice

Minutes of correction count only the errors you spotted. The ones you missed are the expensive ones, and that is the job of the planted items. Score each tool on ten planted items (eight facts, the contradiction, the footnote caveat), wrong page references, invented numbers and arithmetic errors, and record your correction minutes. Then convert misses into minutes: if a missed item would cost you about 20 minutes of client rework when found later, add 20 minutes per miss. That conversion is an assumption you set yourself. The scorecard below is filled in with invented results to show the arithmetic.

Invented scores again: they illustrate the method and say nothing about either product. Without the miss penalty, Tool B looks better at $102.00 against $139.50. With it, Tool A comes out $12.50 a deliverable cheaper, because Tool B never told you the report contradicted itself. Raw time rewards the tool that sounds sure and says less. Risk-adjusted time rewards the one that tells you what is wrong with the source.

Two further adjustments are worth considering. If the deliverable is for a client who will read it closely, raise the penalty per missed item. If it is an internal working note, lower it. And repeat the run with a second, different document before acting on a gap smaller than about $15 a deliverable, since one report can favour either tool.

Confidentiality, client approval and one Project per client

Consulting documents arrive under NDAs, and some clients maintain an approved-tools list. Read the contract before you read any pricing page, because a client who permits only one vendor has made your choice for you. Where use is allowed, put each client's material in its own Project. Claude Free allows up to five Projects, and Claude shares them only on Team and Enterprise; OpenAI says ChatGPT project sharing works on every plan. Business plans on both sides say they do not train on your content by default. On personal plans both vendors have a model-improvement setting, and both offer a chat mode not used for training (Claude's Incognito, ChatGPT's Temporary Chat), which is a backstop and not a permission.

Close each engagement the way you would close a physical file. Delete the Project, delete the chats, and note the date in the engagement record. Reusing last year's work for a new client is a related risk: reusing past client work with AI without leaking client data sets out how to strip identifying detail first. And if your proposals need a sentence about AI assistance, how to mention AI use in client contracts and proposals gives wording to adapt.

Three practices, three different weightings

The same test can lead to different purchases, so set your weights from how you work. A solo strategy consultant whose clients are large corporates should put the client-approved tool at the top of the list and the score second, because a tool the client's security team has not cleared cannot be used however well it scores. A three-person HR consultancy that reuses policy templates cares most about shared Projects and consistent output, which puts team-plan features and sharing rules ahead of a small accuracy gap. An analyst-style consultant who spends the week in spreadsheets should run the ledger-style test as well, using CSV exports, and weight arithmetic and repeatable workings above prose quality.

A short scorecard to copy keeps this honest. Write the weights first and fill in the rest after the runs.

Pricing the work once the tool has saved you time

A deliverable that took twelve hours and now takes eight raises a pricing question. On a fixed fee, the four hours are yours, and the client sees the same price for the same result. On time and materials, you either bill fewer hours or find something better to do with them. A quality log, recording the tool, the checks and the corrections, makes a fixed fee easier to defend, because it shows the review step that the client is actually paying for. If you are weighing the ethics and the commercial side of this, the tutorial on charging clients less when AI speeds up your work covers both.

A decision you can make in one afternoon, and revisit in six months

Run both prompts on both tools with the same 60-page document, then the map prompt and the needle test on a bigger one. Score planted items, count errors, record minutes, and compute cost per deliverable with a miss penalty you have chosen. If the gap is under about $15 a deliverable, pick on the client's approved tools, then sharing needs, then your own preference. If it is larger, take the cheaper tool and move on. Pay for one at $20; consider the $100 tier only if limits cost you more than 32 minutes a month. Keep the other's free tier for spot-checks on high-stakes deliverables, where a second opinion costs nothing.

Whichever tool you pick, the deliverable remains yours. Neither assistant has met the client, felt the mood in the room, or learned which of the owner's numbers is flattering. For more on tools beyond the two assistants, see the seven tools management consultants use from research to decks, and for how much time such tools return across a week, how much time AI can save a solo consultant puts numbers on it.

Questions consultants ask before choosing

Is a team plan worth it for a solo consultant?

Usually not. Both team plans need at least two seats, so a one-person practice pays $40 to $50 a month for the second seat. An individual plan at $20 is the better start. Move to a team plan if a client requires business-grade terms or you add an associate who needs shared Projects.

Can I paste a client's confidential report into a free plan?

Avoid it. Free and individual plans have a setting that decides whether chats can be used to improve models, and your client's NDA or tool policy may forbid third-party AI altogether. Check the contract first, then use a business plan with no training by default, or ask the client to approve the tool.

Which tool handles a 600-page data room better?

Neither vendor can promise it. Claude reads PDFs up to 1,000 pages but sees visuals only in files of 100 pages or fewer; ChatGPT accepts large files, but its pricing page puts the input for one answer at about 320 pages on Plus and Business. Ask each for a section map first, then query section by section, and run a needle test on a page you planted.

How do I show a client that AI use was controlled?

Keep a short log: which tool, which plan, which documents went in, and who checked the output. State in the proposal or engagement letter that AI assists drafting and that a named person reviews every deliverable. Clients usually care more about the review step than about the brand of tool.

Further reads

• The AI Tool Stack a One-Person Consultancy Actually Needs — The wider tool stack a one-person consultancy needs.
• How to Use AI in a Small Consultancy: Proposals, Research and Delivery — Where AI helps across proposals, research and delivery.
• How Consultants Use AI to Write Proposals in Under an Hour — Writing proposals faster once the tool is chosen.
• How Consultants Use AI for Client Research Before Discovery Calls — Research before a discovery call.
• Gamma AI Presentation vs Copilot in PowerPoint for Client Decks: Costs and Fit — The same kind of test for client decks.
• Claude vs ChatGPT for Accounting Firms: Handling Client PDFs — A scoring method for messy client PDFs.
• AI Consulting Report Writing: From Findings to a Client-Ready Draft — Turn a findings log into a client-ready report with evidence tags, a number check on every figure and an executive summary written last.
• Can Consultants Use ChatGPT With Client Data? NDAs and Settings — A clause-by-clause NDA check and a redaction workflow for consultants who want to use ChatGPT on client work.
• AI Tools and AI Development: The Complete 2026 Guide — the AI hub, including every tutorial in the AI-for-business series.

Sources: claude.com/pricing, openai.com/business/pricing, Claude's help article on uploading files, OpenAI's file-uploads FAQ, Anthropic and OpenAI privacy pages (checked 1 November 2026). Client, figures and scores are invented for illustration.