Charlie Chang’s apps

Founder Energy Dashboard

Track work, sleep, fitness, focus, and performance patterns.

Puts sleep, training, focus and output on one timeline so the connection between them is visible. Most founders suspect the pattern; this shows whether it is real for them.

What a v1 does5 features
  • Sleep, activity and focus pulled from the phone and wearables
  • Work output tracked alongside, not separately
  • Correlations surfaced with an honest note on sample size
  • The week's shape shown, so the bad day has a cause
  • Health data never used for anything but this

The market

Proven marketTask and daily planning
50M usersat Todoist, of whom roughly 300,000 pay

That is about 0.6% conversion at the most successful independent task manager there is. Motion went from $2M to $50M in under two years charging $19 to $34 a month, and Sunsama charges $16 to $20. At $9 a month this is priced below both.

Where these numbers come from
CompanyEarnsReachSource
Todoist$26.5M a year50M+ users · ~300k paying customersIndependent estimate
Motion$2M to $50M ARR in under two yearsNot publishedIndependent estimate
Sunsama$16–20/moNot publishedPublished pricing, 2026

Why this audience

This audience connects sleep, training and output as a matter of course - the content treats the body as part of the business. They already wear something that measures it. Seeing whether the correlation is real for them is the natural next question.

Before it can launch

  • HealthKit and Google Fit terms - health data cannot be used for advertising, and Apple requires the privacy policy to say so

What it earns

Drag me Every figure recalculates as you go.

Paying users1,000

0.05% of 2M followers · capped at 50,000

Price per month$9

Opens on the price this idea was costed at, $9.

1,000 paying — 0.05% of 2M followers — × $9 a month = $9,000 a month

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Revenue a month$0123456789,012345678901234567890123456789
Over twelve months$012345678901234567890123456789,012345678901234567890123456789

Fifty thousand paying users is the ceiling every one of these pages is drawn against, not a forecast. It opens at a thousand, the bottom of the range, so the first figures you see are the modest ones. What the cap buys is comparability: the same range on every app, and the percentage of the audience it takes as the number that moves.

Is this the one for your audience?

We fund it, build it, and run it. You bring the audience and take a share of the revenue. Nothing to pay and nothing to build.

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