A Cap Rate Guide That Spends More Time on NOI Than on the Division

Cap rate is the number that gets quoted first in every offering memorandum and verified last in every diligence process. Most online explainers reinforce that habit. They present the formula, run one clean example with round numbers, and move on, which leaves readers able to divide but not able to tell whether the figure they were handed means anything. So it is worth flagging a guide that inverts the emphasis and treats the income statement as the hard part.

The piece in question is Cap Rate Calculator, published as a Kaggle notebook. The venue is unusual for commercial real estate content, and anyone arriving expecting Python will not find any. What is there is a long-form underwriting explainer: the formula and its rearrangements, a step-by-step NOI build, two worked examples, benchmark tables by asset class, a list of common calculation errors, and a section on when the metric should not be used at all.

What it gets right

The strongest section is the NOI walkthrough, and specifically the parts where the guide is willing to be opinionated.

It insists on deducting a property management fee even when the owner self-manages, and it backs the position with the Fannie Mae multifamily underwriting standard, which takes the greatest of 3% of effective gross income, the actual fee, or the appraiser’s concluded market fee, with a 2.5% floor available only under specified conditions. That level of citation is rare in introductory content, and it settles an argument that comes up constantly with owner-operators trying to justify a thinner expense load.

It also draws the line between real estate income and operating-business revenue, using an owner-operated gas station as the example: fuel and convenience-store sales are not rent, and folding them into NOI produces a cap rate that describes a business, not a building. Buyers of owner-user assets and single-tenant properties get this wrong regularly, and the guide is right to raise it before the arithmetic starts.

The vacancy discussion is handled with a worked figure rather than a warning. A property with $200,000 of potential gross income, $80,000 of operating expenses, and a $2 million value shows a 6% cap rate at full occupancy and a 5% cap rate once a 10% vacancy and credit-loss allowance is applied. One hundred basis points from a single assumption is the sort of demonstration that changes how someone reads a rent roll, particularly alongside the guide’s caution about sellers advertising 100% occupancy while major leases approach expiration.

A few other details signal that the author has underwritten deals rather than only written about them:

• The unlevered nature of the metric is explained properly. Debt service is excluded because two buyers with different loan structures still face the same property-level income, and the guide routes leveraged questions to cash-on-cash return and IRR instead of muddying the cap rate.
• The reciprocal of the cap rate is presented with an explicit caveat that 12.5 years at an 8% cap is not a payback period, since it assumes flat NOI and ignores capex, financing, and sale proceeds. Plenty of articles present that shorthand with no disclaimer at all.
• Property tax reassessment on sale appears in the mistakes list, which is exactly the line item that quietly breaks a first-year pro forma.
• The closing section on when cap rate is the wrong tool covers land, fix-and-flip, ground-up development, and seasonal income, and offers the gross rent multiplier as a rougher screening alternative.

The two examples are structured sensibly, moving from a listed self-storage facility priced at $1.2 million with $96,000 of NOI to a reverse calculation that values a property at a market cap rate and then shows the value falling from $1.6 million to $1.5 million on a 50 basis point shift. The second example makes the sensitivity point better than any amount of prose would.

Where it falls short

The benchmark tables are the weakest part, and the guide half-admits it. Multifamily is represented by an average transaction cap rate, while the industrial and retail figures are average asking cap rates for single-tenant net-lease properties. Those are different populations measuring different things, and presenting them in one table invites readers to compare them directly even though the accompanying text warns against it. The niche table has the same issue in sharper form, mixing going-in rates by property class, average listed NNN rates, and observed ranges for two specific brands. Credit where it is due: the bowling alley row simply states that no defensible national benchmark exists, which is a more honest answer than most publishers would allow.

All of these figures are dated to specific 2026 quarters, which is good practice, but nothing in the piece indicates a refresh cadence. Benchmark content ages faster than methodology content, and a reader landing on this in a year will get accurate formulas alongside stale comparables.

The larger omission is causal. The guide explains how to compute a cap rate and how to sanity-check the inputs, but says almost nothing about what moves cap rates in the first place. There is no discussion of the spread over the ten-year Treasury, no treatment of cap rate compression and expansion, and no framing of why the market rate for an asset class shifted 75 basis points between vintages. Someone finishing this article can rebuild a seller’s NOI competently and still have no idea why the exit assumption in their model is the single largest driver of returns. Exit cap rate appears only in the FAQ, which understates its importance.

Two smaller notes. The guide includes a promotional section for the publisher’s own analytics tool, clearly labeled and reasonably informative about what it does, though readers should recognize it as vendor content. And given that the piece lives on Kaggle, the absence of any actual notebook, model, or downloadable spreadsheet is a missed opportunity. The platform is built for exactly that, and the “calculator” here is a link elsewhere rather than something a reader can fork and run.

Verdict

This is a useful resource for brokers, new analysts, and private investors evaluating their first income-producing asset, and a reasonable thing to hand someone who keeps repeating an advertised cap rate without having seen the rent roll. Its practical value sits in the NOI construction, the mistakes list, and the honest treatment of when the metric does not apply. Read the benchmark tables as directional only, check the dates against current market data, and pair it with material on capital markets if you need to understand why cap rates move rather than only how to calculate them.