Pitch deck mistakes: 10 reasons investors say no fast

An investor opens your deck between two meetings. She scrolls. By minute two she has already decided whether the other slides get a look. And you aren’t in the room to change her mind.

Ten pitch deck mistakes get a quick no. Each one below comes with a slide before and after the fix. Our guinea pig is a made-up Milan startup that sells booking software to physiotherapy clinics at €120 a month, so please don’t quote its numbers to anyone. Still no pitch deck? Start with the slides investors expect, in order.

How long do investors spend on a pitch deck?

Less than three minutes. That’s DocSend’s line in its 2025 research, and its own data put the all-time low at 2 minutes 24 seconds for the average deck, in the last quarter of 2023. DocSend also says most decks run to roughly 20 pages with about 50 words a slide. Divide the minutes by the pages and you get seven to nine seconds a slide.

One more number, with a warning label. DocSend’s 2020 pre-seed data shows investors giving over four minutes to decks that later raised money, and only 1 minute 30 seconds to decks that didn’t. Which came first, the clear deck or the interested investor? Nobody knows. Either way, you’re writing for a reader who skims.

Pitch deck mistakes in the opening slides: one-liner and why now

1. No one-liner. The first instruction in Sequoia’s guide to writing a business plan is to define your company in one declarative sentence. It warns that this is harder than it looks. Michael Seibel of Y Combinator has editing rules for that sentence. Cut jargon, acronyms, marketing speak and vague words like “platform”. Then “make it sound dumber than you think it should”.

Seibel’s test costs almost nothing. Write two sentences on what you do, email them to a smart friend and ask for the idea back in their own words. A fuzzy answer means the sentence needs work. Our guide to writing your startup in one sentence goes deeper.

2. No why now. Sequoia gives “Why now?” a section of its own. Suppose the idea was possible five years ago. Then the obvious question is why nobody built it. Your slide answers with something that changed (a technology, a rule, a habit, a cost), says when it changed and shows proof that it’s working already.

Mistake	Before	After
No one-liner	A next-generation AI platform that reimagines patient engagement for healthcare providers.	Booking software that stops physiotherapy clinics losing money on no-shows: patients confirm by text and cancelled slots refill from a waiting list.
No why now	Healthcare is going digital.	A named change, a date and proof. Invented here: “Patients already book haircuts and restaurant tables from their phones. Clinics still confirm by phone call. Our first 12 clinics switched to text confirmation in a week.”

Market, traction and vanity metrics

3. A market slide built from the top down. “The healthcare software market is worth billions and we only need 1%.” Anyone can type that sentence, which is why it proves nothing. Seibel prefers the bottom-up route: “figure out where comparable products are sold, how many of them are sold, and what % of those sales you could take”. Start from customers you can name and the price you charge. That’s the honest version of TAM, SAM and SOM.

4. Traction buried. Suppose the number that proves people pay you (investors call it traction) shows up on slide 11. Ten slides of explanation come first, and each gets about seven seconds. Move it to slide two. Better still, put it in the one-liner.

5. Vanity metrics. Visits, sign-ups, followers and letters of intent show interest. They don’t show a business. a16z puts it bluntly: “Letters of intent and verbal agreements are neither revenue nor bookings.” Show paying customers, MRR (the money that repeats every month) and how many customers stay. Our guide to unit economics shows how to turn them into the numbers an investor checks next.

Mistake	Before	After
Top-down market	“The healthcare software market is worth billions. We only need 1%.”	“Say 3,000 clinics fit our profile (3 to 10 therapists). At €1,440 a year each (€120 × 12), that’s €4.32M a year we can sell to today.”
Buried traction	Slide 11 of 14: “Strong early interest from the sector.”	Slide 2, and inside the one-liner: “38 paying clinics, up from 12 five months ago.”
Vanity metrics	12,000 website visits, 2,300 newsletter sign-ups, 4 letters of intent.	38 paying clinics, €4,560 a month in recurring revenue (38 × €120), 18 of the 20 clinics that started three months ago still paying.

Team, financials and the ask

6. A team slide with no proof. DocSend’s 2020 guide to seed decks found that the team slide was the only slide present in every successful deck. Kevin Hale of Y Combinator reduces the logic to one line: “Investors invest in teams not slides.” Titles, degrees and words like “passionate” don’t tell an investor why you can solve this problem. Past work does.

7. Financials that don’t match the model. The same DocSend guide found that when a deck includes financial slides, they “will be by far the most viewed”, and that only 58% of successful seed founders included them at all. So if you show numbers, expect them to be read, and expect someone to open the spreadsheet next. Every figure on the slide should come from one named scenario in your financial model, with the version and date on the slide.

8. A vague ask. Geoff Ralston of Y Combinator wrote that the ask comes down to this: you are raising for N months (usually 12 to 18) and will therefore need $X. Say how much, for how long, what it buys and which milestone you’ll reach. And add up your use-of-funds percentages. If they reach 110%, somebody will notice.

Mistake	Before	After
Team with no proof	Marco, CEO: MBA, passionate about healthcare innovation. Giulia, CTO: 10 years in IT.	Marco ran operations for a 14-clinic physiotherapy group for six years. Giulia built that group’s booking system. Between them they’ve lived the problem from both sides.
Numbers differ from the model	Slide: “Year 3 revenue: €1M.” The spreadsheet says €648,000.	“Year 3: 450 clinics × €1,440 = €648,000”, copied from the base case of the model, with version and date on the slide.
Vague ask	“We’re raising a seed round. Use of funds: product 40%, marketing 40%, operations 30%.” (It adds up to 110%.)	“We’re raising €300,000 for 18 months, to go from 38 to 150 paying clinics (€18,000 a month). €150,000 sales and onboarding, €120,000 product, €30,000 legal and admin.”

Too much text, and the deck that needs a voiceover

9. Walls of text. Kevin Hale’s rule is that a simple slide “expresses one idea”. Try saying in one sentence what yours proves. Can’t? Then it’s two slides pretending to be one. At 120 words it’s barely a slide at all, more a memo in a frame. DocSend’s average is about 50 words a slide, which is already a lot for seven seconds.

10. A deck that only works when you present it. Sometimes you’ll present live, with a deck built for the room. Often you’ll send it, and Ralston’s advice is that the deck be “a coherent leave-behind”. Hale’s test costs nothing: show it to a stranger and ask what it means.

Mistake	Before	After
Walls of text	“Our solution is a cloud-based, mobile-first booking platform with automated reminders, waiting-list management and analytics, built for practices of every size…” (110 words)	One sentence, one large screenshot of the booking screen, one number: “38 clinics”.
Needs a voiceover	Slide 6 is a diagram with the words “flywheel” and “network effects”. It makes sense only while you’re talking.	Sentences a stranger can follow with the sound off. After two minutes they should be able to say what you do, who pays and what you want.

Pitch deck checklist: run it before you hit send

New to fundraising? The beginner’s map from zero to a first round shows where the deck sits. When yours is ready, run this list.

1. Read slide 1 aloud. Is the one-liner a sentence a stranger could repeat?
2. Is your best number on slide 1 or 2?
3. Does the market slide start from customers you can name and a price you charge?
4. Does every figure match your model, to the euro?
5. Does the team slide say what each person has done that matters here?
6. Does the ask have an amount, a number of months and a milestone, as in the €300,000 for 18 months and 150 clinics above? The vague ask above adds up to 110%. Does yours stop at 100?
7. Is your busiest slide still one idea, in about 50 words or fewer? Count, don’t eyeball.
8. Has a stranger read the PDF for two minutes without your help? Fix what they got wrong, then write the cold email to investors that goes with it.

Our guide to raising capital for a startup in Italy puts the deck in context with the rest of the round.