Last Tuesday a reader sent me a deal to look over: a six-unit building, asking $1.15M, net operating income of about $72,000. He wanted to know if it was "a good one." I ran the math in my head before I even opened the rent roll — that's a 6.3% cap, and the answer to "is it good" depends entirely on three things he hadn't told me yet.
That's the trap almost every new investor falls into with cap rates. The number itself is easy. What it means — for you, for this asset, in this market, right now — is where people get hurt. I've watched friends buy "8% cap" properties that lost money and "4.5% cap" properties that made them rich. So let's untangle this properly.
Here's what understanding cap rates for real estate investors actually requires: the formula, yes, but also the context nobody puts on the flyer.
Key Takeaways
- The cap rate is net operating income divided by price — nothing more, nothing less.
- It ignores your mortgage entirely, which is why two investors can see the same property very differently.
- A "good" cap rate does not exist in the abstract. It only exists relative to the asset class, the market, and the risk you're accepting.
- Small errors in your NOI estimate move the cap rate more than most people realize.
- Cap rate describes a stabilized asset. If you're buying a value-add project, it's the wrong tool for day one.
- Compare cap rates within a market, never across markets, unless you know exactly what you're adjusting for.
The cap rate formula, and why it trips people up
The math is embarrassingly simple:
Cap rate = Net Operating Income ÷ Property Price
You buy a small retail unit for $600,000. After collecting rent, paying taxes, insurance, maintenance, and setting aside a reserve, you're left with $45,000. That's a 7.5% cap rate. Done.
The problem is almost never the division. It's the NOI.
What actually goes into NOI
Net operating income is gross rental income, minus vacancy, minus operating expenses. It excludes your mortgage payment, your income taxes, and capital expenditures. That last exclusion is where I see people fool themselves constantly.
A mistake I made early on: I bought a duplex and counted the roof replacement as an operating expense in my NOI. It made my cap rate look like 8.2%. It wasn't. A roof is a capital expense — it doesn't belong in NOI at all, but it absolutely belongs in your head when you're deciding whether to buy. I ended up replacing that roof eighteen months in for $14,000, and my "great deal" became painfully average.
Operating expenses typically include:
- Property taxes and insurance
- Property management fees, whether you hire one or not (pay yourself for the work)
- Repairs and maintenance, averaged over years, not this month
- Utilities you cover, plus a vacancy allowance and a capital reserve
That's it. Four buckets. Miss one and your cap rate is fiction.
Why the number is only as honest as your inputs
Sellers love to present "pro forma" cap rates — numbers based on rents that could exist after renovations, occupancy that hasn't happened yet, and expenses that conveniently forgot property taxes went up. Those are hopes dressed as math. When I underwrite anything, I rebuild the NOI from scratch using the last two years of actual statements. If a broker pushes back, that's a signal, not a nuisance.
What is a good cap rate for a real estate investment?
There is no universal number, and anyone who gives you one without asking about your market is guessing. What I can tell you is how to build your own reference point.
Cap rates move with three things: asset class, market, and risk. A stabilized apartment building in a supply-constrained city trades at a much lower cap rate than a strip mall in a shrinking town, because everyone wants the apartment and the risk is lower. Lower cap rate means lower expected return, but also lower volatility.
What is a good cap rate in real estate — context first
The honest answer for most investors I talk to: a good cap rate is one that clears your cost of capital with room to spare, and still makes sense after you've called every expense by its real name. If your borrowing rate is higher than your cap rate, you're losing money on leverage — that's not a deal, that's a donation.
Ranges I've seen hold up across the deals I've personally reviewed, by asset type:
| Asset type | Typical cap rate range | What it tells you |
|---|---|---|
| Stabilized multifamily, strong market | 4–6% | Low risk, low yield, lots of competition |
| Value-add multifamily, secondary market | 6–8% | You're paid for the renovation risk |
| Retail, single tenant | 6.5–9% | Depends heavily on the tenant's credit |
| Small commercial, tertiary market | 8–11% | Higher yield, harder exit, thin buyer pool |
| Anything with a "for lease" sign and a story | 12%+ | Usually a reason |
Notice the pattern? Higher cap rate means higher perceived risk. That's the whole game.
Is a higher or lower cap rate better in real estate?
Higher is not automatically better, and this trips up almost everyone at first. A 12% cap rate often means the market believes the income is unstable — a tenant about to leave, a neighborhood in decline, or expenses the seller is hiding. A 5% cap rate on a well-located building with a ten-year tenant can be the safer bet by miles.
Lower cap rate means you're paying more for each dollar of income, which usually reflects confidence. Higher cap rate means you're being compensated for taking on something uncertain. Neither is "better." The question is whether the compensation matches the risk you're actually taking.
What does a 7.5% cap rate mean?
A 7.5% cap rate means the property generates $7.50 of net operating income for every $100 of purchase price. On a $1M building, that's $75,000 of NOI.
Here's the part people skip: that 7.5% is the yield on an unleveraged basis. If you buy with 75% debt at, say, 6.5% interest, your actual cash-on-cash return can be noticeably higher — or lower, if the debt costs more than the cap rate. The cap rate says nothing about your checkbook.
What is the 7% rule in real estate?
The "7% rule" you'll see floating around isn't a formal underwriting standard — it's a rough screening heuristic some investors use: if a property's cap rate lands at or above roughly 7%, it's worth a closer look. Think of it as a filter, not a verdict.
I use something similar myself. Anything below 6% in my target markets gets a hard look at whether the growth story justifies it. Anything above 10% gets an equally hard look at why it's above 10%. The 7% line is just where I start paying attention, not where I stop thinking.
Is 7% a good cap rate?
For a stabilized asset in a market where borrowing costs sit around 6%, yes — it's a reasonable, defensible number. In a market where money is cheap, 7% might be excellent. Where debt is expensive, 7% might barely cover your financing. The number doesn't exist in a vacuum.
What I'd tell the reader who sent me that six-unit deal: a 6.3% cap rate isn't bad or good on its own. It's a starting point for a conversation about what the rents actually are, what the expenses actually are, and what you're actually financing it with.
Want to check a deal yourself? Use a straightforward cap rate calculator: plug in NOI and price, read the percentage, then go back and audit every line of that NOI. The calculator never lies. Your inputs might.
Cap rate at entry vs. exit — the part most guides ignore
The cap rate you buy at is your going-in cap rate. The cap rate you sell at is your exit cap rate. The gap between them is where a lot of real returns are made or destroyed.
Say you buy at a 7% cap rate, improve the property, raise NOI from $70,000 to $95,000, and sell three years later when the market's cap rate is 6.5%. You just got paid twice — once for the income growth, once for the cap rate compression. Flip the scenario and sell into a rising cap rate environment, and you can do everything right operationally and still walk away with less than you planned.
Nobody controls where cap rates go. That's the risk you accept when you buy. My rule: underwrite the exit at a cap rate at least 50 basis points worse than today's, and only buy if the deal still works. If it does, you've built yourself a margin. If it doesn't, you were relying on the market to bail you out, and that's not a strategy.
The bottom line
Understanding cap rates for real estate investors comes down to this: the formula is trivial, the context is everything. Use it to compare like assets in like markets. Rebuild the NOI yourself. Never let a pro forma do your thinking. And remember that the number on the flyer tells you about the seller's expectations far more than it tells you about your returns.
The next time someone hands you a deal and asks "is it good?", you'll know the cap rate is just the opening line of the conversation — and you'll know exactly which questions to ask next.
