How Much Should You Invest Per Month?

"How much should I invest?" is one of those questions that gets a dozen different answers depending on who you ask. Some people say 15% of your income. Others say whatever's left after bills. The real answer is more nuanced — and it starts with understanding where you are right now.

The Simple Benchmark: 15% of Gross Income

If you want a single number, financial planners generally recommend investing 15% of your gross income for retirement. That includes any employer match on your 401(k). So if your employer matches 3%, you'd need to contribute 12% yourself to hit 15% total.

But here's the thing — 15% is a target for people who start in their 20s and want to retire around 65. If you're starting later, you'll need a higher percentage. If you have other goals (early retirement, a house down payment), the number shifts again.

The percentage matters less than the consistency. Someone investing 8% every month for 20 years will outperform someone who invests 20% for six months and then stops.

Start With What You Can Actually Afford

If 15% feels impossible right now, don't let that stop you from starting. Any amount is better than zero — and here's why the math backs that up.

Investing just $100/month at an average 8% annual return gives you:

After 10 years: ~$18,400
After 20 years: ~$59,300
After 30 years: ~$150,000

That's $36,000 in actual contributions turning into $150,000. The other $114,000? That's compounding doing the work for you. If you want to see exactly how these numbers change with different amounts, try our Compound Interest Calculator.

If $100/month is a stretch, start with $50. Or $25. The point is getting the compounding clock started. You can always increase later.

The Framework: How to Decide Your Number

Rather than picking an arbitrary percentage, work backward from your financial situation:

Step 1: Cover the essentials first

Before you invest anything, make sure you have:

A starter emergency fund ($1,000–$2,000 minimum)
High-interest debt under control (if you're paying 20%+ APR on credit cards, that comes first)
Your basic bills covered without stress

If you're still working on these, that's okay. Focus here first, then redirect money to investing as each piece falls into place. We cover the full priority order in our beginner's guide to investing.

Step 2: Capture your employer match

If your employer offers a 401(k) match, contribute at least enough to get the full match before doing anything else. A 100% match on 3% of your salary is a guaranteed 100% return — no investment will beat that.

Step 3: Build from there

Once you're capturing the match:

Comfortable with your budget? Push toward 15% total (including the match)
Budget is tight? Stay at the match level and increase by 1% every time you get a raise
Aggressive goals? Some people target 25–50% savings rates for early financial independence. That's the exception, not the rule — but it's worth knowing the spectrum

If you don't have a clear picture of your budget yet, our Budget Calculator can help you see exactly where your money is going and how much you can realistically redirect toward investing.

When to Increase Your Contributions

The best time to bump up your investing is when your income changes and you haven't adjusted your lifestyle yet:

After a raise: Redirect at least half of the increase toward investments before lifestyle creep absorbs it
After paying off a debt: Take the monthly payment you were making and invest it instead. You're already used to that money being "gone"
After a windfall: Tax refunds, bonuses, and cash gifts are the easiest money to invest because you weren't budgeting around it

The goal is to ratchet up over time. Going from 5% to 8% to 12% to 15% over a few years is much more sustainable than trying to jump straight to 15% and burning out.

What If You're Starting Late?

If you're in your 30s or 40s and haven't started, you'll need to invest more aggressively to catch up — but it's far from hopeless.

Starting at 35 instead of 25 means you have roughly 30 years instead of 40. To end up in a similar place, you'd need to invest about twice as much per month. That sounds steep, but you also probably earn more at 35 than you did at 25, so the higher dollar amount is often achievable.

The worst thing you can do is feel like it's "too late" and not start at all. You can start investing with $100 or less — the barrier is lower than you think.

The Bottom Line

There's no magic number that works for everyone. The right monthly investment is one that balances your current needs with your future goals — and that you can sustain consistently over years, not just months. Start with whatever you can, automate it, and increase it over time. Your future self will thank you for every dollar you put to work today.

Want to see how your monthly investment grows over time? Try our free Compound Interest Calculator to run the numbers.