Rental numbers for ZIP 63123 (Affton, MO)
Negative cash flow at today's 7.78% investor rate with 25% down; the typical home breaks even at about 2.1%.
- Gross yield
- 7.3%
- rent x 12 / price
- Est. cap rate
- 3.4%
- NOI / price
- Cash flow
- -$635/mo
- at 7.78%, 25% down
- Typical price
- $248,000
- Zillow ZHVI, Aug 2026
- Typical rent
- $1,512/mo
- Zillow ZORI, Aug 2026
The pro forma
Typical home, default assumptions
| Operator | Line | Amount | Source |
|---|---|---|---|
| Gross rent | $18,144 | ||
| Vacancy | $907 | ||
| Management | $1,379 | ||
| Property tax | $3,051 | ||
| Insurance | $1,907 | ||
| Maintenance | $2,480 | ||
| Net operating income | $8,420 | ||
| Loan payments | $16,038 | ||
| Cash flow | -$7,618 |
| Operator | Line | Amount | Source |
|---|---|---|---|
| Typical price | $248,026 | ||
| Down payment (25%) | $62,007 | ||
| Loan | $186,020 | ||
| Rate | 7.78% | ||
| Monthly payment | $1,337 | ||
| Cash in | $69,447 | ||
| Cash-on-cash return | -11.0% | ||
| DSCR | 0.52 | ||
| Break-even rate | 2.15% |
Assumptions
Change them in the calculator- Down payment25%
- A common minimum for investment-property and DSCR loans.
- Interest rate7.78%
- Freddie Mac 30-year 7.03% (week of 2026-09-24) + 0.75 point investor premium.
- Loan term30 years
- Fixed, fully amortising.
- Closing costs3% of price
- Added to cash invested.
- Insurance$1,907 a year
- NAIC 2023 average homeowners (HO-3) premium for Missouri, $1,589, x 1.2 for a landlord policy.
- Maintenance1% of price a year
- The 1% rule of thumb; older homes run higher.
- Vacancy5% of rent
- About 18 days empty a year.
- Management8% of collected rent
- A typical full-service fee; zero if you self-manage.
Trends
Five years to August 2026
- Price, 12 months
- +2.5%
- Rent, 12 months
- +2.1%
- Rent minus price growth
- -0.4 pts
- positive means yields are improving
Show the numbers
| Month | Typical value | Rent |
|---|---|---|
| Aug 2021 | $200,081 | $1,102 |
| Aug 2022 | $218,590 | $1,219 |
| Aug 2023 | $229,576 | $1,310 |
| Aug 2024 | $239,314 | $1,382 |
| Aug 2025 | $241,898 | $1,481 |
| Aug 2026 | $248,026 | $1,512 |
Rent references
Two sources, never blended
| Source | Studio | 1 bed | 2 bed | 3 bed | 4 bed |
|---|---|---|---|---|---|
| HUD Small Area FMR, FY2026 | $960 | $1,000 | $1,230 | $1,580 | $1,830 |
| Zillow observed rent, Aug 2026 | $1,512 typical, all home types | ||||
HUD's Fair Market Rent is the 40th percentile gross rent (rent plus utilities) for a standard unit, and it is what Section 8 vouchers pay against. Zillow's index tracks asking rents on listed homes. The two measure different things, so they are shown side by side and never averaged. HUD area: St. Louis, MO-IL HUD Metro FMR Area.
Property tax
- Effective rate
- 1.23%
- ZIP area, ACS
- At the typical price
- $3,051/yr
Median real estate taxes paid divided by median home value, Census ACS 2020 to 2024. St. Louis County: 1.21%. Actual bills depend on the assessment, exemptions and any non-homestead rate.
Supply
- Permits per 1,000 households
- 2.4
- St. Louis County, last 12 months
- National percentile
- 29th
- among US counties
994 new housing units permitted in 2025-09 to 2026-08, Census Building Permits Survey. A high figure means more new supply competing for tenants.
Nearby ZIP codes
| ZIP | Distance | Typical price | Rent | Gross yield | Cash flow /mo |
|---|---|---|---|---|---|
| 63125Lemay | 2.7 mi | $206,000 | $1,110* | 6.5% | -$667 |
| 63126Crestwood | 2.7 mi | $340,000 | $1,250* | 4.4% | -$1,479 |
| 63109Saint Louis | 3.2 mi | $273,000 | $1,179 | 5.2% | -$1,090 |
| 63119Webster Groves | 3.2 mi | $382,000 | $1,658 | 5.2% | -$1,496 |
| 63116Saint Louis | 4.1 mi | $187,000 | $1,150 | 7.4% | -$486 |
| 63111Saint Louis | 4.3 mi | $122,000 | $986 | 9.7% | -$143 |
| 63143Maplewood | 4.5 mi | $258,000 | $1,269 | 5.9% | -$957 |
| 63139Saint Louis | 4.8 mi | $229,000 | $1,359 | 7.1% | -$617 |
* HUD Fair Market Rent, 2 bedroom (no Zillow rent index for that ZIP).
Run the numbers on a real listing
The calculator opens with this ZIP's figures. Swap in a listing's price and rent, your rate and your costs.
Open the calculator for 63123Questions
- Is 63123 good for rental property?
- On the typical home here, priced at $248,000 and renting for $1,512 a month (Zillow ZORI, Aug 2026), the gross yield is 7.3% and the estimated cap rate is 3.4%. At a 7.78% investor rate with 25% down, estimated cash flow is -$635 a month. The median gross yield across the 8,418 ZIP codes with full Zillow data is 5.6%. These are figures for a typical property, not a judgement on any particular one.
- What is the typical rent in 63123?
- Zillow's observed rent index for 63123 was $1,512 a month in August 2026, across all home types. HUD's FY2026 Small Area Fair Market Rent for a 2-bedroom here is $1,230, the 40th percentile of gross rents and the basis for Section 8 payment standards.
- What is the property tax rate in 63123?
- The effective property tax rate is about 1.23% of value (median taxes paid divided by median home value, Census ACS 2020 to 2024). On the typical $248,000 home that is about $3,051 a year. Your bill depends on the assessment and local exemptions.
- What interest rate makes a rental in 63123 break even?
- About 2.15%. Below that rate, the typical home here cash-flows with 25% down and the default costs; above it, it does not. Today's investor rate used here is 7.78%.
- How fast are prices and rents changing in 63123?
- Over the 12 months to August 2026, the typical home value changed +2.5% and the typical rent changed +2.1%. Prices rising faster than rents pushes yields down.
Sources and method
- Zillow Home Value Index (ZHVI), mid tier, smoothed and seasonally adjusted
Zillow Research. Read: 2026-08.
Typical home value by ZIP, county, metro and state, and the price trend.
- Zillow Observed Rent Index (ZORI), all homes plus multifamily, smoothed
Zillow Research. Read: 2026-08.
Typical market rent by ZIP, county and metro, and the rent trend (tier A pages).
- HUD Small Area Fair Market Rents, FY2026
US Department of Housing and Urban Development. Read: FY2026.
Rent by bedroom count for every ZIP. The rent used on tier B pages, and a reference on all pages. It is the 40th percentile gross rent, so it runs below market.
- American Community Survey 5-year estimates, 2020 to 2024 (B25103 median real estate taxes paid, B25077 median home value, B11001 households)
US Census Bureau. Read: 2020 to 2024.
Effective property tax rate (median taxes paid divided by median value) by ZIP code tabulation area, county and state; households for the permits ratio.
- Freddie Mac Primary Mortgage Market Survey, 30-year fixed (FRED series MORTGAGE30US)
Freddie Mac via the Federal Reserve Bank of St. Louis. Read: 2026-09-24.
The weekly 30-year rate. The site adds a disclosed investor premium to it for the loan payment.
- Building Permits Survey, county monthly files
US Census Bureau. Read: 2025-09 to 2026-08.
New housing units permitted in the last 12 months per 1,000 households, a supply-pressure signal.
- NAIC Homeowners Insurance Report, data for 2023
National Association of Insurance Commissioners. Read: 2023.
Average HO-3 homeowners premium by state, multiplied by 1.2 as a landlord-policy assumption.
Data: Zillow Research (ZHVI, ZORI), HUD, US Census Bureau, Freddie Mac. Every formula is on the methodology page.
Estimates from public data for a typical property. Not investment, tax or legal advice. Your property, financing and costs will differ.