B2C · AI spreadsheet assistant

How Formula Bot grows

7 tactics and 14 figures from 1 interview.

Formula Bot started as a free AI tool that writes Excel formulas and grew from two Reddit posts that went viral. The free traffic ran up large AI costs, so the founder tried donations, a sponsor and site ads before adding a paywall for unlimited use. Calls with users then pushed it toward broader data analysis, partly to stay ahead of free ChatGPT.

Formula Bot's founder posted the free tool to r/excel with just a title and link, and it became the top post of the day and then the week.Formula Bot
A commenter's suggestion led to a post on r/InternetIsBeautiful that drew about 10,000 upvotes and kept the tool viral for months, but with no paywall it ran up about $5,000 in OpenAI costs within days.Formula Bot
To cover that bill, a Stripe donation link with a personal note brought back a few thousand dollars; a one-week sponsor ad drew many clicks, while Google ads made little and weren't worth it.Formula Bot (1)Formula Bot (2)
A relaunch with free limited use and paid unlimited use, with the price raised from $2.99 to $6.99 and then $9, reached about 5,000 paying users out of about 750K and about $26K MRR, with about 5% churn.Formula Bot
The founder did users' spreadsheet work for free, but only on a call where they gave feedback, and said this turned the formula tool into a broader data analysis product.Formula Bot
Against free ChatGPT, Formula Bot first competed by working inside Excel and Sheets with each user's language preset, then moved to harder-to-copy features; about 10% of churn was put down to ChatGPT.Formula Bot

Summary written 2026-10-05 from the tactics below. Figures are as founders stated them.

About Formula Bot

What it is: AI tools for spreadsheets: ChatGPT-style AI inside Excel and Google Sheets, text-to-formula generators, and a data analyzer where you upload data and get answers, charts and models in plain language.
Who it's for: People who work with data and spreadsheets (analysts, Excel users worldwide)
Business model: freemium subscription for unlimited usage
Pricing: Early: $2.99 (also stated as $3) for unlimited usage; Raised to $6.99, then $9 for unlimited usage
Launched: July 2022
Team: Solo founder, side project alongside a full-time job
Funding: bootstrapped
Outcome: ~$26K MRR, ~5,000 paying users, ~750K users after ~1.5 years

As described in the interviews, not independently verified.

Formula Bot's 7 tactics

Formula Bot · B2C · AI spreadsheet assistant

Post your free tool in the niche subreddit with just a title and link

Top post of the day, then of the week, in r/excel

After showing coworkers, posted the MVP to the Excel subreddit. Title: 'AI Excel Formula Generator', mentioning it was free; the post body was just the link, nothing else.

Workedcommunitypr-launch

Starter Story · 2024-02-11

Formula Bot · B2C · AI spreadsheet assistant

Repost your tool to r/InternetIsBeautiful after a commenter suggests it

~10,000 upvotes and thousands of users; viral for months, but $5K API bill in days

A couple of days after the r/excel post, a commenter suggested posting on r/InternetIsBeautiful, so he posted it there too. The app was free with no paywall, so every visitor cost OpenAI API money.

Mixedcommunitypr-launch

Starter Story · 2024-02-11

Formula Bot · B2C · AI spreadsheet assistant

Add a Stripe donation link to a free tool that went viral

Recouped a few thousand dollars of a ~$5,000 API bill

With the app free and a ~$5,000 OpenAI bill, he put up a Stripe link with a personal note: 'Hey, my name's David. I built this app. It went viral... feel free to donate.'

Workedpayments-checkout

Starter Story · 2024-02-11

Formula Bot · B2C · AI spreadsheet assistant

Do users' spreadsheet work for free on a call, in exchange for feedback

Founder says it turned a formula tool into a full data analysis product

About once a week a user emailed their Excel file asking for help the formula generator couldn't give (e.g. building a report). Even for non-paying users he agreed to do the work, but only live on a phone call, and on every call they had to answer what they liked, didn't like, and what ideas they had. Combined with asking coworkers who work with data.

Workedfeature-developmentcustomer-support

Starter Story · 2024-02-11

Formula Bot · B2C · AI spreadsheet assistant

Charge for unlimited use and raise the price from $2.99 to $9

~5,000 paying users and ~$26K MRR; ~5% churn

A few months after launch, relaunched with logins and a paywall: free limited use, pay for unlimited usage. Started at $2.99 during a race to the bottom with copycats, then raised to $6.99 and then $9.

Workedpricingpaywall

Starter Story · 2024-02-11

Formula Bot · B2C · AI spreadsheet assistant

Put the AI inside Excel and Sheets, with each user's language preset

Kept users against free ChatGPT early on; only ~10% of churn blamed on ChatGPT

Against free ChatGPT and copycats, competed on convenience and customization: formulas generated inside Excel and Google Sheets so users never leave the spreadsheet or write a long prompt; at signup users set their speaking language and their Excel language (e.g. Spanish speakers who use English Excel, and vice versa). Later moved to features ChatGPT and Microsoft can't copy, such as the data analyzer.

Mixedpositioning-nicheintegrations-marketplaces

Starter Story · 2024-02-11

Formula Bot · B2C · AI spreadsheet assistant

Earn from free traffic with Google ads and a one-week sponsor

Sponsor ad drove lots of clicks; Google ads made a few bucks, not worth it

Before adding subscriptions, tried running ads on the site: Google ads, plus a one-week sponsored ad for the host of an Excel esports competition broadcast on ESPN, who reached out at peak virality. David mocked up the ad creative himself.

Mixedad-monetization

Starter Story · 2024-02-11

Formula Bot by the numbers

Metric	Value	Context	Said in
users	750K users approximate	Total users over ~1.5 years	Starter Story 2024-02-11 1:47
paying users	5,000 users approximate	Pay for unlimited access	Starter Story 2024-02-11 1:47
mrr	USD 26K/month approximate		Starter Story 2024-02-11 1:47
valuation	USD 1M estimate	'valued at over a million dollars'; intro claim only, no basis given in the body	Starter Story 2024-02-11 0:00
time to milestone	a couple weeks approximate	Time to build the no-code MVP in Bubble	Starter Story 2024-02-11 6:30
count	10K upvotes/one-time approximate	Upvotes on the r/InternetIsBeautiful post; also thousands of comments and thousands of visitors	Starter Story 2024-02-11 7:27
cost	USD 5,000/one-time approximate	OpenAI API costs run up within days of going viral while the app was free	Starter Story 2024-02-11 7:56
revenue	a few thousand dollars approximate	Donations via a Stripe link to recoup API costs	Starter Story 2024-02-11 8:22
price	USD 2.99	Early price for unlimited usage (also rounded to '$3')	Starter Story 2024-02-11 13:38
price	USD 6.99	Intermediate price for unlimited usage	Starter Story 2024-02-11 13:38
price	USD 9	Current price for unlimited usage; billing period not stated	Starter Story 2024-02-11 13:38
churn	5% approximate	Period not stated	Starter Story 2024-02-11 14:12
share	10% approximate	Share of churn reasons attributed to free ChatGPT	Starter Story 2024-02-11 14:12
activity volume	1 emails/week approximate	Users emailing their Excel files asking for help, which became feedback calls	Starter Story 2024-02-11 10:48

Topics

Reddit marketing for apps2 Community-led growth2 Launching an app: waitlists, press and launch day2 Price tests and price increases1 App localization and international growth1 Web-to-app funnels and web checkout1 Picking a niche and positioning an app1 App paywall strategy1 Pricing a subscription app1

Interviews

I Built a $1M AI App [No Code] · Starter Story · 2024-02-11