My recommendation: If your goal is “I want to connect my cards, forget about it, and have my spare change invested automatically,” choose Acorns. If you're going to invest more substantial amounts regularly, I'd also compare it with a low-cost robo-advisor or brokerage because Acorns' flat monthly fee can be relatively expensive on a small balance.
If you tell me roughly how much you spend per month and whether you want stocks, ETFs, or a totally hands-off portfolio, I can tell you which option is likely to cost you the least.
When it comes to putting your spare change on autopilot, the clear industry pioneer and standard for round-up investing is Acorns . However, depending on your broader financial goals and fee preferences, a few alternatives are worth considering.
Here are the top contenders for investing spare change automatically:
Acorns — Best for pure spare-change investing. It links to your debit or credit cards, rounds up your purchases to the nearest dollar, and automatically invests the difference into a diversified, expert-built portfolio of ETFs. It also offers retirement accounts (Acorns Later) and checking/savings options, though it operates on a monthly subscription fee model (starting around $3/month for basic tiers), which means small balances can see a high fee impact percentage-wise. You can check it out directly on the Acorns Website.
Stash — Best for learning as you invest. Stash also offers automatic round-ups alongside fractional share investing, but it focuses heavily on micro-learning, guiding you on why you are buying specific stocks or funds rather than just putting everything strictly into a rigid robo-portfolio. Like Acorns, it runs on a monthly subscription fee.
Robinhood / Fidelity / SoFi — Best for commission-free recurring investments. While these traditional and zero-commission brokerages don't always do automated "card round-ups" in the traditional sense, they allow you to set up recurring automated transfers (e.g., $5 a week or $10 a paycheck) into fractional shares with $0 monthly subscription fees . For smaller amounts of spare change, avoiding a fixed monthly fee can keep more money working for you.
If you'd like to narrow this down, tell me:
Roughly how much spare change do you expect to invest per month?
Are you looking strictly for a set-it-and-forget-it portfolio , or do you want to pick individual stocks?
I can help you calculate whether a subscription-based app or a free brokerage with recurring transfers makes more sense for your budget.
If your goal is specifically “round up every purchase and automatically invest the spare change into a diversified ETF portfolio,” the app that most directly matches that description is usually Acorns. It was built around that exact workflow: linking a card or bank account, rounding purchases to the next dollar, and investing the accumulated change into a diversified ETF portfolio.
That said, the “best” choice depends on whether you value simplicity, fees, control, or broader investing features:
App
Best fit
Round-ups
ETF portfolio automation
Key considerations
Acorns
Easiest hands-off spare-change investing
Yes
Yes
Strong match for beginners; subscription fees can matter when balances are small.
Betterment
Robo-advisor with broader planning tools
Generally no native purchase round-ups
Yes
Offers automated diversified portfolios and features such as tax-loss harvesting on eligible taxable accounts.
Wealthfront
Automated investing with more portfolio tools
Generally no native purchase round-ups
Yes
Robo-advisor approach with automated investing features.
SoFi Invest
Investing plus other financial products
Not the core feature
Optional automated investing
Better if you want a broader financial app rather than pure micro-investing.
Stash
Learning while investing
Some automation features
Yes
More hands-on choice of investments than Acorns.
My shortlist by use case
You want “set it and forget it” spare-change investing: Acorns is the closest fit.
You expect your account to grow and want more robo-advisor features: Betterment or Wealthfront may be worth comparing.
You want to learn and eventually choose investments yourself: Stash may fit better.
A few things to check before signing up:
Monthly fee vs. your balance — a flat subscription can represent a large percentage of a small account.
ETF expense ratios — diversified portfolios often use low-cost ETFs, but compare the underlying funds.
Account type — taxable brokerage vs. IRA can have different tax implications.
Emergency savings first — investing apps work best when you are not relying on invested money for near-term expenses.
For the exact feature you described, I’d start by comparing Acorns’ fees and ETF choices against a low-cost robo-advisor like Betterment or Wealthfront, especially if you plan to build a larger balance over time.
The industry pioneer and most widely recognized app for automatically rounding up daily purchases and investing that spare change into a diversified portfolio of exchange-traded funds (ETFs) is Acorns.
The Gold Standard: Acorns
How it works: You link your debit or credit cards. When you buy something (like a coffee for$3.2 5 ), Acorns automatically rounds the purchase up to the nearest dollar ($4.0 0 ) and sets aside the difference ($0.7 5 ). Once your round-ups hit$5 , it automatically invests that spare change into a professionally managed, diversified portfolio of ETFs tailored to your risk tolerance.
The Portfolios: Acorns builds your portfolio using low-cost ETFs covering domestic stocks, international stocks, emerging markets, and bonds.
Cost: Acorns operates on a monthly subscription model rather than a percentage-of-assets fee for smaller accounts. Plans typically range from$3 to$1 2 per month depending on whether you just want the basic investing tier or higher tiers that include retirement accounts, checking/savings, and family features.
Keep in mind: Because of the flat monthly fee, is best used as a micro-investing tool to build a habit with spare change. If your account balance is very low, a$3--$4 /month fee can eat heavily into your returns, so it is most efficient when you enable recurring daily/weekly deposits alongside your round-ups to accelerate your growth.
Acorns
Alternatives to Consider
Qapital: Offers a similar "Round-Up Rule" to save and invest spare change, but it functions more like a hybrid personal finance/banking app with custom rules-based gamification. Investing features require an upgraded subscription tier.
Traditional Robo-Advisors (Betterment / Wealthfront): While they don't feature automatic "round-ups" from your daily coffee runs, they are far superior if you want to invest larger sums into a diversified ETF portfolio with a low annual management fee (typically 0.2 5% of assets under management) and advanced tools like tax-loss harvesting.
If you'd like to narrow this down, tell me:
Do you prefer a flat monthly subscription fee or a percentage-based management fee?
Are you looking strictly for micro-investing (spare change) , or do you plan to make larger recurring monthly deposits?
