How to start investing in college: a practical guide for students with limited income
You don't need much money to start investing in college. You need some money and a lot of time — and at 20, time is the one thing you have more of than anyone else reading this. The math of starting at 20 vs. starting at 30 produces outcomes so different they almost seem like different financial systems. They're the same system. The only variable is when you start.
The verified numbers: $75/month from age 20
At 7% average annual return (monthly compounding, r = 0.005833/month), investing $75/month starting at 20:
At 30 (10 years, 120 months): (1.07229)^10 = 2.00978
FV = $75 × (2.00978 − 1) / 0.005833 = $75 × 173.1 = $12,983
At 40 (20 years): (1.07229)^20 = 4.03927
FV = $75 × (4.03927 − 1) / 0.005833 = $75 × 521.1 = $39,083
At 50 (30 years): (1.07229)^30 = 8.11774
FV = $75 × (8.11774 − 1) / 0.005833 = $75 × 1,220.1 = $91,508
At 65 (45 years): (1.07229)^45 = 23.129
FV = $75 × (23.129 − 1) / 0.005833 = $75 × 3,794 = $284,550
Your total contributions from 20 to 65: $75 × 12 × 45 = $40,500. Your balance at 65: $284,550. That's $244,050 produced by compound growth alone — six times what you actually put in.
| Monthly Investment (start age 20) | Balance at 65 | Total Contributed | Growth from Compounding |
|---|---|---|---|
| $50/month | $189,700 | $27,000 | $162,700 |
| $75/month | $284,600 | $40,500 | $244,100 |
| $100/month | $379,400 | $54,000 | $325,400 |
All figures assume 7%/yr average annual return (monthly compounding) from age 20 to 65 with no interruptions.
The student who starts at $50/month and slowly increases contributions over time will end up even further ahead than these figures suggest — because every increase early in the timeline compounds for decades. Start small. Start now. Increase when you can.
Roth IRA vs. regular brokerage: which account for a student?
For most college students, the Roth IRA is the right first account — if you have earned income (part-time job, research stipend, freelance work, etc.). Here's why:
- Roth IRA: After-tax contributions (no deduction now), but growth and qualified withdrawals are completely tax-free. At a student's tax rate — which is likely 10% or even 0% — there's almost no cost to contributing after-tax. The future tax-free growth is extremely valuable.
- Regular brokerage: No contribution limits, no earned income requirement, no withdrawal rules. But gains are taxed each year (dividends, capital gains). Best for money you might need before 59½.
If you have earned income and don't plan to touch the money until retirement, the Roth IRA wins. If you might need it sooner, use a regular brokerage account — or split contributions between both.
One important rule: the Roth IRA contribution limit is the lesser of $7,500 or your earned income for the year. A student earning $5,000 at a part-time job can contribute up to $5,000 to their Roth IRA. See the full step-by-step Roth IRA beginner guide for how to open one.
What to invest in: the one-fund answer
For a student just starting out, the right investment is one total U.S. stock market index fund. That's it.
- At Fidelity: FZROX (0.00% expense ratio — free to own, no minimum)
- At Vanguard: VTI (0.03% expense ratio, buy in dollars — no minimum for ETFs)
- At Schwab: SWTSX (0.03% expense ratio)
One fund covers thousands of companies across every sector. You don't need sector funds, individual stocks, or anything more complicated than this for the first five years of investing. The enemy of good investing isn't not knowing the best fund — it's not starting because you're trying to optimize before you begin.
A real example: Maya, college junior at 20
Maya is a 20-year-old junior working 12 hours a week at a campus coffee shop, earning $1,400/month. She decides to open a Roth IRA at Fidelity and invest $75/month automatically into FZROX.
She finds the $75 by making two changes: she drops one streaming service she barely uses ($17/month) and eats in twice a week instead of ordering delivery (saves about $60/month). Total lifestyle change: minimal. Outcome over time: $284,550 by age 65.
By her 30th birthday — just 10 years in — her Roth IRA holds approximately $12,983. She hasn't done anything impressive: no research, no stock picks, no market timing. She set up an automatic transfer a decade ago and didn't touch it.
The account grows faster from there because the base is larger. By 40, it's $39,083. By 50, $91,508. The last 15 years, from 50 to 65, the balance more than triples — from $91,508 to $284,550 — without Maya adding a meaningful amount of extra money. That's the late-stage power of compounding.
How to actually find $50–$100/month
The objection most students have is real: money is tight. These suggestions are specific and non-preachy:
- Cancel one subscription: The average person has 4–6 subscriptions they use occasionally. One cancellation = $10–$20/month immediately.
- Cook twice a week instead of ordering: Two fewer delivery orders/week at $15–20 each = $120–$160/month savings. Even one fewer order = $60–80.
- Direct a portion of your next raise: When your part-time hours increase or you get a better job, direct half the increase to investing before lifestyle adjusts.
- Tax refund: If you're getting a federal tax refund (common for students who had withholding), deposit it directly into the Roth IRA as a lump-sum contribution instead of spending it.
You're not looking for sacrifice. You're looking for $50–$100 that will otherwise drift into spending you won't remember at 30. That amount, invested consistently from 20, produces six figures by retirement.
One practical step to take this week
Open a Roth IRA at Fidelity.com (search "Roth IRA," no minimum, takes 15 minutes). Fund it with whatever you have — even $50. Set up a $50–$100/month automatic contribution. Buy FZROX with the balance. Then close the app and go back to your actual life. Check it again in a year.
That's it. The investment decisions get more sophisticated over time if you want them to. For now, starting beats optimizing every time.