Girl Math.
A budgeting app that speaks the internet's language, turning the "girl math" trend into a playful way to track spending.
- My role
- Founder and designer: concept, product, UI and launch
- Type
- Personal project
- Platform
- Mobile app
- Status
- Launched, promoted through short-form video
The idea
Budgeting apps lecture. This one laughs along.
"Girl math" is the joke logic people use to justify spending: returns are free money, cash doesn't count, an expensive dress is cheap per wear. Girl Math takes that logic and builds a real budget tracker around it, so tracking spending feels like part of the joke instead of a chore.
How it works
Justify it
Calculators
Six "logic" calculators, including Free Money, Cost-Per-Wear, Emotional ROI and Cash Payments, each with its own swipeable card.
Track it
Budget goals
Every justification is still a real transaction, rolling up into a monthly budget and categories like food, bills and shopping.
Keep coming back
Streaks + quotes
Streaks, "smart girl moments" and a shareable Girl Math of the Day quote give people a reason to open it daily.
Launch
I took Girl Math from concept to launch myself, then promoted it the way its audience discovers things: short vertical videos for TikTok, Instagram Reels and YouTube Shorts, built around a hook, a demo of the app and a punchline.
What I took away
Tone is a product decision. The humor isn't decoration on top of a budgeting app; it's the reason someone downloads it, and the reason they come back to log the next purchase.