ListingResearchOS
Rental Property Investor OS — everything in one file, works offline

Interactive dashboard

Rental Property Investor OS, Interactive Landlord Dashboard, Cash Flow Tracker, Cap Rate Calculator, Portfolio ROI

Built for Buy-and-hold landlords and small real-estate investors (30-55) with 2-15 long-term rentals who juggle three or four separate spreadsheets and still can't answer their real portfolio cash-on-cash return without a 20-minute math session; want one private command center for properties, tenants, cash flow, and returns that opens in any browser with no login and no subscription

$22.00 one-time purchase · instant download
Works offlineNo loginAutosaves locallySingle HTML file

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Interactive demo · a few tabs unlocked

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The dashboard

What it is

Built for buy-and-hold landlords and small real-estate investors (30-55) with 2-15 long-term rentals who juggle three or four separate spreadsheets and still can’t answer their real portfolio cash-on-cash return without a 20-minute math session; want one private command center for properties, tenants, cash flow, and returns that opens in any browser with no login and no subscription. Rental Property Investor OS, Interactive Landlord Dashboard, Cash Flow Tracker, Cap Rate Calculator, Portfolio ROI It is a browser-native interactive dashboard that lives in a single HTML file, with nothing to install.

What is Rental Property Investor OS?

Rental Property Investor OS is an interactive dashboard that opens in your web browser. It is one self-contained HTML file — you download it once, double-click it, and it runs. It is built for buy-and-hold landlords and small real-estate investors (30-55) with 2-15 long-term rentals who juggle three or four separate spreadsheets and still can’t answer their real portfolio cash-on-cash return without a 20-minute math session; want one private command center for properties, tenants, cash flow, and returns that opens in any browser with no login and no subscription.

What is included in Rental Property Investor OS?

5 sections, all in the one file:

  • Portfolio Overview
  • Properties Registry
  • Rent Roll + Tenants
  • Cash Flow + Expenses
  • Returns Engine

Does Rental Property Investor OS need Excel, Google Sheets or a subscription?

No. There is no app to install, no account to create, no login and no recurring fee. It opens in Chrome, Safari, Edge or Firefox on macOS, Windows, iPad or Chromebook, and it keeps working offline once the file is on your machine.

Where does Rental Property Investor OS store my data?

On your own device, in your own browser. Nothing is uploaded, no account is created and no analytics are collected. You can export a backup file at any time and load it on another computer.

How much is Rental Property Investor OS and how is it delivered?

$22, delivered as an instant download the moment you pay. Because it is a digital file, all sales are final.

More about Rental Property Investor OS

You own the units. But you’re still pulling up four different spreadsheets to answer the question every landlord eventually has to answer: “What am I actually making on this portfolio?” Rent comes in. Mortgage goes out. Then taxes, insurance, maintenance, vacancy, repairs. What’s left? What’s your cap rate? What’s your cash-on-cash return? Most landlords doing it right in Excel still have to do that math by hand every time a number changes.

This is the dashboard that eliminates that.


EXCLUSIVE ZONE: Returns Engine, Live Cap Rate, Cash-on-Cash ROI, and NOI Calculator

Go to Tab 5. Enter any property’s purchase price, rent, expenses, and mortgage. The dashboard returns cap rate, cash-on-cash ROI, net operating income, monthly cash flow, annual cash flow, estimated equity, and portfolio-level totals, instantly. Change a rent assumption. Watch every number update in real time. Every Etsy competitor ships a static spreadsheet you fill in by hand. This one calculates. Nothing in this market does that in a single offline browser file.


WHAT’S INSIDE (5 Interactive Tabs)

  1. Portfolio Overview: KPI command center, total units, portfolio occupancy rate, total monthly cash flow, estimated portfolio value, and net equity across all properties. See your whole operation at a glance.

  2. Properties Registry: Per-unit master record, address, purchase price, current value, mortgage details, rent, property type, and acquisition date. The foundation every other tab builds from.

  3. Rent Roll + Tenants: Active lease tracker, lease start/end dates, monthly rent, security deposit, payment status, and tenant contact. Know who owes what and when leases expire before they do.

  4. Cash Flow + Expenses: Per-property income and expense log grouped by IRS Schedule E categories, insurance, repairs, management fees, mortgage interest, property taxes, utilities, depreciation. Export-ready for your accountant.

  5. Returns Engine (EXCLUSIVE): Live calculator, cap rate, cash-on-cash ROI, NOI, monthly and annual cash flow, equity, and portfolio ROI rollup. Type a new rent or expense assumption. Every metric recalculates immediately. No Etsy competitor ships this in a browser file.


Why this beats the spreadsheets you’ve seen

  • One file. Opens in any browser. No Excel licence. No Google login.

  • Your data never leaves your device, saves in localStorage, JSON export for backup.

  • Change any input on Tab 5 and your whole portfolio math updates instantly.

  • Schedule E expense groupings built in, hand it to your CPA, not a chaos pile.

  • Works offline. Open it at the bank, on a plane, in the courthouse.


Comes with

  • The interactive dashboard (HTML, opens in any browser)

  • A4 printable workbook PDF

  • US Letter printable workbook PDF

  • Instructions PDF, how to open, save, back up, and restore

  • HOW-TO-SAVE.txt, plain text quick reference


THIS IS FOR YOU IF…

  • You own 2-15 long-term rentals and you can’t answer “what’s my portfolio cash-on-cash return” without a 20-minute spreadsheet session

  • You use three or four different Google Sheets to track different properties and they all have different formats

  • Tax season arrives and your Schedule E categories are a mess

  • A lease is expiring in 60 days and you didn’t notice until the tenant mentioned it

  • You know your rents. You know your mortgages. You want software that does the rest.


Your data is safe

Everything lives in your browser’s localStorage. Nothing is uploaded to any server. No Google account. No Notion workspace. No subscription. The Export Backup button downloads a private .json file to your computer. Load Backup restores it instantly on any device. Your portfolio data stays on your machine, always.


Free notion upgrade

Message the shop after purchase, every buyer gets the free Notion conversion template within 24 hours. Same five tabs, same calculations, synced across devices.


INSTANT DOWNLOAD. LIFETIME ACCESS. ONE FILE. ANY BROWSER. NO SUBSCRIPTION. EVER.

Your rental portfolio, finally organized in 20 minutes.

5 Tabs included

  • Portfolio Overview

    KPI command center: total units, portfolio occupancy rate, total monthly cash flow, estimated portfolio value, and net equity across all properties at a glance

  • Properties Registry

    Per-unit master record: address, purchase price, current value, mortgage details, rent, property type, and acquisition date — the foundation every other tab builds from

  • Rent Roll + Tenants

    Active lease tracker: lease start/end dates, monthly rent, security deposit, payment status, and tenant contact — know who owes what and when leases expire before they do

  • Cash Flow + Expenses

    Per-property income and expense log grouped by IRS Schedule E categories — insurance, repairs, management fees, mortgage interest, property taxes, utilities, depreciation — export-ready for your accountant

  • Returns Engine

    Enter purchase price, rent, expenses, and mortgage; get live cap rate, cash-on-cash ROI, NOI, monthly and annual cash flow, equity, and portfolio ROI rollup that recalculates the moment you change an assumption

Exclusive Feature

Returns Engine is a live cap rate, cash-on-cash ROI, and NOI calculator. Enter any property's purchase price, rent, expenses, and mortgage and it returns cap rate, cash-on-cash return, net operating income, monthly cash flow, annual cash flow, estimated equity, and portfolio-level totals instantly. Change a rent assumption and every number updates in real time. Every Etsy competitor ships a static spreadsheet you fill in by hand — none calculate. Nothing in this market does this in a single offline browser file.

This is built into the fifth tab and is unavailable in any static template, spreadsheet, or Notion template on the market.

Gallery

Why the Rental Property Investor OS exists: the problem it removes for you
Every tab of the Rental Property Investor OS: Portfolio Overview, Properties Registry, Rent Roll + Tenants, Cash Flow +
Returns Engine is a live cap rate — the part of the Rental Property Investor OS no spreadsheet does
Everything included in the Rental Property Investor OS, feature by feature
Rental Property Investor OS runs offline in your browser, no login and no account
Before and after: scattered notes versus the Rental Property Investor OS
Rental Property Investor OS open on macOS, Windows, iPad and phone in any browser
Who the Rental Property Investor OS is for, in their own situation
Rental Property Investor OS, instant download, one file that is yours forever

Learn more

Before you buy

Frequently asked questions

What is Rental Property Investor OS?
Rental Property Investor OS is an interactive dashboard that opens in your web browser. It is one self-contained HTML file — download it once, double-click it, and it runs. No app, no account, no subscription.
Does Rental Property Investor OS need Excel or Google Sheets?
No. It is not a spreadsheet and does not open in one. It runs in Chrome, Safari, Edge or Firefox on macOS, Windows, iPad or Chromebook, and keeps working offline.
What is included in Rental Property Investor OS?
5 sections in a single file: Portfolio Overview, Properties Registry, Rent Roll + Tenants, Cash Flow + Expenses, Returns Engine.
Does it work offline?
Yes — completely. The dashboard is a single HTML file. Once downloaded, it runs entirely in your browser with no internet connection needed. All data autosaves to your browser's localStorage.
Which devices and browsers are supported?
Works in Chrome, Edge, Safari, and Firefox on macOS, Windows, iPad, and Chromebook. No app to install, no account to create. Just open the file.
What is your refund policy?
All sales are final. This is an instant download delivered in full at payment, so it cannot be returned. If a file will not open or a feature does not work as described, that is a defect and it gets fixed at no cost — email hello@listingresearchos.com and you will get a corrected file.
How do I install it?
There is nothing to install. After purchase, download the HTML file. Double-click to open in your browser. That's it. A HOW-TO-SAVE.txt is included explaining how to back up and restore your data.
Is my data private?
Completely. Everything runs locally — no login, no analytics, no data sent to any server. Your data is stored only in your browser's localStorage. You own it entirely.

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