When I owned 3 rental properties, I could keep the numbers in my head. Now that I’m managing 9, I’ve learned the hard way that “the portfolio feels profitable” and “Property C is actually losing me 18,000 yen a month” can both be true at the same time. It took me almost 2 years of sloppy record-keeping before I built a system that shows me exactly which units earn their keep and which ones are quietly dragging everything else down.
If you own more than one rental, tracking return on investment (ROI) property-by-property isn’t optional u2014 it’s the only way to know where to put your next renovation budget, your next loan, or your next weekend of DIY labor.
Why Property-Level ROI Beats Portfolio-Level Averages
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The financial mindset shift that made property investment possible on a salary.
Averages hide problems. Across my 9 properties, my blended cash-on-cash return sits around 7.2% in a typical year, which sounds healthy. But that number is really an average of one property returning 14% and another returning barely 1.5% after a costly roof repair. If I only looked at the combined bank balance, I’d never notice that the 1.5% property has been underperforming for 3 straight years. Tracking each property separately is what lets me catch that kind of drag before it becomes a 5-year pattern.
The Simple Spreadsheet System I Use for 9 Properties
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Track every yen in and out u2014 the foundation of profitable landlord accounting.
I don’t use property management software u2014 with 9 units I found most of it overbuilt for a solo landlord. Instead I run one spreadsheet with a tab per property plus a summary tab that pulls from each one automatically. Every tab has the same layout, so I can compare properties side by side without translating formats in my head. It took me one weekend, roughly 6 hours, to build the template the first time; every property I’ve added since has taken about 20 minutes to set up.
- Monthly rent collected (actual, not scheduled)
- Fixed costs: loan payment, property tax (a portion of the annual bill divided by 12), insurance
- Variable costs: repairs, vacancy loss, management time valued at a flat 2,500 yen/hour
- Capital improvements, tracked separately from repairs
- Net cash flow and running annual total
What I Track for Each Property, Monthly and Annually
Every month I spend about 25 minutes updating actuals u2014 I do it the first Saturday of the month with coffee, before anything else gets in the way. Annually, each property gets a deeper review where I recalculate purchase price plus all-in renovation cost against current rent and current market value. For a property I bought for 8.2 million yen and put 1.4 million yen into before renting it out, my all-in basis is 9.6 million yen, and that’s the number I use for ROI, not the purchase price alone. Landlords who forget to add renovation cost into the basis end up overstating their returns significantly.
Cash-on-Cash Return vs Cap Rate: I Use Both
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Cap rate tells me how the property performs independent of financing u2014 net operating income divided by current value. Cash-on-cash tells me how my actual cash invested is performing, which matters more once a mortgage is involved. On one property with a 20% down payment of 1.6 million yen, a net cash flow of 240,000 yen a year gives a cash-on-cash return of 15%, even though the cap rate on the same property is closer to 5.5%. I look at cap rate when deciding whether a property is worth holding long-term, and cash-on-cash when deciding whether my financing strategy is actually working.
How I Use the Numbers to Decide Where to Reinvest
Once a year, usually in January, I rank all 9 properties by cash-on-cash return and look hardest at the bottom 2. Last year that review flagged a property returning only 2.1%, and digging into the tab showed the cause wasn’t rent or vacancy u2014 it was a water heater and a fence repair eating into an otherwise solid unit. I fixed both myself for about 45,000 yen in materials instead of hiring it out at an estimated 140,000 yen, and the property’s return climbed back to 6.8% the following year. Without the per-property breakdown, I’d have just assumed the whole portfolio needed attention instead of one specific unit.
Common Mistakes That Skew the Numbers
The biggest mistake I made early on was mixing repair costs with capital improvement costs in one category. A 15,000 yen faucet repair and a 900,000 yen kitchen renovation are not the same kind of expense, and lumping them together made older properties look artificially worse than newer ones. The second mistake was forgetting to account for my own labor. I do most repairs myself, and if I don’t assign even a modest hourly value to that time, my ROI numbers look better than they really are u2014 which makes it harder to decide honestly whether hiring a contractor would actually be worth it.
That’s the approach I use across all 9 of my properties, and it’s the only reason I caught a struggling unit last year before it became a real problem.
Renovation Cost Reduction Checklist (60% Savings Method)
My step-by-step process management template that cut renovation costs by 60% across 3 apartment buildings over 15 years.
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15 years of landlord experience u00b7 3 apartment buildings u00b7 DIY renovations that saved millions of yen. Browse all articles at diytosan.com
