This Stupidly Simple App Makes $100K/Month

With no idea of his own, browsed sites like Acquire.com looking for a validated idea. Found an app similar to Go Tall listed for ~$20K; didn't buy it but built his own version, confirmed by his own teen experience of googling height calculators. Advises not to abandon an idea just because it exists already (e.g. calorie trackers still make $30K/month next to Cal AI): copy it with your own tweaks.

Noticed that under height videos on TikTok, people post their age, height and parents' heights, wanting a prediction. Made reply-to-comment videos predicting those commenters' heights. Inbound DMs requesting predictions served as proof that people care.

For about a month, made 10 TikToks every day himself to experiment until a format worked. Because there was only one format and one distribution channel, attribution was easy: he knew how many downloads 100K views produced, which told him what he could afford to pay creators.

Once the format worked, replicated it himself on two other TikTok accounts and had his girlfriend post it on her account, to check that the format works regardless of who posts it.

DM'd about 50 people a day pitching a super easy, already-proven video format. Because the format was simple, creators were willing to make it for a very cheap price. Creator pay was set from the known views-to-downloads ratio.

Optimized the paywall (no details given) while scaling content a little more.

After scaling the first format with creators, explored even more content formats (not described).

Only after reaching ~$30K/month organically did he start paid ads, using the content formats already proven organic. No platforms, spend or creative details given.

Commenters kept adding more personal details to get more accurate predictions, so onboarding asks all of them: a long quiz on top of CDC growth data, each question linked to research studies that adjust the prediction (e.g. a puberty-stage quiz). The final height prediction is behind the paywall ($35/year or $5/week).

Free features include stretches, meal scanning and sleep logging. The height prediction updates over the weeks based on logged growth and habits, becoming more accurate the more users log, giving a reason to keep the subscription after the first prediction.