The Side Hustle Math That Actually Works
Most side hustles fail on arithmetic, not effort. A simple framework for deciding what's worth your nights and weekends.
Everyone wants a side hustle. Almost nobody does the math before starting one. Here's the back-of-the-napkin model I run before committing a single weekend.
The three numbers
Every side hustle comes down to three inputs:
- Hourly reality — revenue minus costs, divided by all the hours (including the unglamorous ones).
- Ceiling — how big can this realistically get before it caps out?
- Decay — does it keep paying when you stop, or die the moment you do?
A dog-walking gig has a great hourly reality and zero decay resistance. A digital product has a brutal first month and excellent decay resistance. Know which one you're signing up for.
A worked example
Say you're considering a paid newsletter:
| Input | Estimate |
|---|---|
| Subscribers (yr) | 500 |
| Price / month | $8 |
| Hours / week | 6 |
| Annual revenue | ~$48,000 |
| Effective rate | ~$154 / hr |
That effective rate only shows up if you hit the subscriber number. The honest move is to discount it by your confidence. At 30% confidence you're really modeling ~$46/hr — still good, but a different decision.
The rule I follow
Don't start a hustle whose best case is a worse use of time than getting better at your main thing.
Side income should either compound (build an asset) or buy you optionality (learn a skill, build an audience). If it does neither, it's just a second job with worse benefits.
Coffee's on me if you want to argue about the model — reach out.
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