Girl / Boy Math
Personal Finance Edition
The funny lies your brain tells you about money — and the real math hiding underneath. Bring your drink. We're going to do some receipts.
I'm Jorrel.
Founder and operator — I build companies for a living (currently Diem360 and Whale Labs; before that I co-founded a YC-backed startup, AnythingLLM). Roughly a decade watching money move in and out of businesses and my own bank account.
The important disclaimer: I am not a financial advisor. I'm just someone who's personally made most of the mistakes in this deck — so you can get them at a discount.
Consider this "things I wish someone told me at 22," not investment advice.
Welcome to Sip & Learn.
A casual series where we learn one genuinely useful thing over drinks. Today: money. Next time: Networking — but the Lazy Way · Thu July 16.
Cadence: Every Thursday in July · 6–8 PM
- Interrupt with questions anytime
- Screenshot anything (especially the cheat sheet)
- No judgment — we've all done girl math
[Drop any event-specific announcements, shoutouts, or sponsor thanks here.]
The Delusion.
First, the funny lies — the stuff your brain says to make spending feel free.
What even is girl/boy math?
It started as a TikTok bit: the delightful mental gymnastics we do to make spending feel free. Today we find out how expensive the joke actually is.
Girl math
- "I paid cash, so it doesn't count."
- "It was on sale — I saved money by spending money."
- "Anything under $5 is basically free."
Boy math
- "It's not spending, it's an investment."
- "I'll use it every day." (uses it twice)
- "Free shipping if I add $50 more to the cart."
Which of these have you actually said?
Tap all that apply. No judgment — okay, a little.
tap a few and watch the room light up
Girl/Boy Math — Hall of Fame
Every one of these is a tiny magic trick your brain plays to make spending feel free.
It's all the same bug.
Every rationalization does one thing: it moves money from Future You to Present You — and hides the receipt. Your brain is wired for right now (that's present bias), and it keeps money in mental "pockets" so it doesn't feel like real spending (mental accounting).
Good news: you can't delete the bug, but you can build guardrails around it. That's the rest of this talk.
The Girl/Boy Math Translator
Type in a purchase. See what your brain says vs. what it actually costs.
Not "never buy it." Just — see the real price tag before you decide.
The Real Math.
Enough dunking on ourselves. Four moves that actually work.
Track it. You can't fix what you can't see.
A loose starting frame — 50 / 30 / 20. Not a law, just training wheels. Drag your take-home pay:
rent, food, bills
fun, treats, this app
save + invest + debt
High rent city? The ratios bend. The point isn't the percentages — it's that every dollar gets a job before it disappears.
Pay yourself first.
Income − Spending = whatever's left to save
Spoiler: nothing's ever left.
Income − Savings = what you get to spend
Automate the transfer on payday. You never see it, you never miss it.
One auto-transfer beats a year of willpower. Set it and forget it.
Kill high-interest debt first.
Credit card "girl math" says minimum payments are fine. The card company loves that. At 24% APR, a $3,000 balance paid at the minimum:
No investment reliably beats a 24% guaranteed return. Paying off that card is the best investment you'll find.
Start compounding early.
Time does the heavy lifting, not the amount. Play with it:
Waiting 10 years to start costs you $0 — for the exact same monthly amount.
Assumes ~7%/yr average return, contributions until 65. Markets wobble; the direction holds.
The "latte factor" — with an asterisk.
Any small recurring habit, invested instead. Drag it:
The asterisk: the point isn't "never buy coffee." A $6 latte won't ruin you. It's that small recurring things are quietly enormous — so aim that power at stuff you don't even enjoy first.
And yes — boy math is real too.
Girl math
- "I saved money by buying it on sale."
- "Returning it = free money."
- "Cash purchases don't count."
Boy math
- "The truck's a business expense."
- "It's not spending, it's an investment." (the JPEG / the sneakers)
- "Buying in bulk saves money." (buys 40 lbs of it)
Same bug, different flavor. Calling something an "investment" doesn't make it one.
Chase the real villains.
- High-interest debt sitting unpaid
- Lifestyle creep as your income grows
- Not investing at all (cash quietly loses to inflation)
- Zero emergency buffer → one bad month = new debt
- Your $6 latte
- The occasional treat that you love
- Spending on things that genuinely matter to you
- Guilt — it's useless, budgets run on systems not shame
Optimizing coffee while ignoring 24% debt is the most expensive kind of "saving."
Do one thing Monday.
Not a 10-step plan you'll abandon by Friday. One move:
SET UP ONE AUTOMATIC TRANSFER
Even $50 on payday →
savings or a Roth IRA
Future You just got their first paycheck. Everything else builds on this.
Momentum > perfection. Start embarrassingly small, then raise it later.
The whole talk on one card.
Give every dollar a job
You can't fix what you can't see. 50/30/20 is fine training wheels.
Save first, spend the rest
Automate the transfer on payday. Beats willpower every time.
High-interest debt is a fire
Paying off 24% APR is a guaranteed 24% return. Unbeatable.
Start early, start small
Time does the work. The best day was 10 years ago; second best is today.
Mindset: every purchase is a trade with Future You. Just make the trade on purpose.
Intermission. ↻
Refill your drink, stretch, heckle a stranger. Back in ~10 for the grown-up stuff — 401(k)s, IRAs, and taxes.
← Scan to RSVP
@sawtelleneighborhoodcollective
Level 2: Adult Mode.
The stuff nobody actually taught you — 401(k)s, IRAs, taxes. Speedrun version. Each one could be its own night, so treat this as the trailer.
Your job might be handing out free money.
A 401(k) is a retirement account through work. The magic words: employer match. If they match your contributions and you don't contribute, you're literally declining a raise. (Bonus: it lowers the income you're taxed on now. Cap is $24,500 in 2026.)
Rule of thumb: always contribute at least enough to grab the full match. It's the only guaranteed 100% return you'll ever get. "i'll start next year" denied
The Roth IRA: a young person's cheat code.
An IRA is a retirement account you open yourself (up to $7,500 in 2026). The Roth flavor: pay tax on the money now, then it grows and comes out completely tax-free forever. Young and in a low bracket? Paying the tax now is a steal.
Pay a little tax on the $7,500 seed today → it grows to $100k+ → withdraw all of it, $0 tax. You taxed the small number.
Skip the tax today → it grows to $100k+ → pay tax on the whole harvest in retirement. You taxed the big number. Better if you're high-income now, worse if you're not.
Not tax advice — but for most people in their 20s, Roth is the crowd favorite for a reason.
Wait — what's a "deduction"?
You don't pay tax on every dollar you earn. The government lets you knock a chunk off first, then taxes what's left. That chunk is your deduction. There are two ways to size it — and you just take whichever is bigger.
The flat coupon 🎟️
A fixed amount off, no receipts, no questions — $16,100 if you're single. ~9 in 10 people take this and never think about it again.
Save your receipts 🧾
Skip the coupon and add up certain real expenses — mortgage interest, big state/property taxes, charity. If that pile beats the coupon, use it instead.
and no, you can't deduct your rent 😔 which is exactly why the coupon wins for most of us.
Standard vs. itemized: take the bigger one.
So — which is bigger for you? Plug in your numbers. (Renters with no donations: just watch the flat coupon win.)
Renting, no big donations? Standard wins every time — that's most of us. Itemizing mostly kicks in once you've got a mortgage.
That was the trailer.
Each of those deserves its own night. On the menu for future sessions:
Retirement accounts, actually explained
401(k), Roth, IRA — which to fund first, and why.
Taxes without tears
W-2s, deductions, and why you got that refund (or didn't).
Credit scores & debt
What actually moves the number — and how to stop feeding the card.
Investing 101
Index funds, brokerages, and starting with $20.
Vote for the next topic — shout it out or DM @sawtelleneighborhoodcollective.
What's your worst girl/boy math?
Confess it to the group. We'll do the receipt live. Then grab another drink — Future You is covered.
Sip & Learn · Personal Finance, Girl/Boy Math Edition
Come to the next one.
Follow along, send me your worst girl-math confessions, or just say hi.
Thanks for sipping & learning. Future You says hi.