Population Within Radius
By Marko Visic · Updated Oct 7, 2026
Calculate total US population, density, and demographics inside any circular area. Median income, age, education, housing, top counties, and top postal places. Free, no sign-up.
Population Within Radius
Calculate total population and demographics for any circular area in the US
It sums the population of every US ZIP Code Tabulation Area (ZCTA) whose centroid falls inside your radius, using US Census American Community Survey data. Demographics are population-weighted averages across the same ZIPs.
Population, income, age, housing, and education are from the American Community Survey 2024 5-year estimates via SimpleMaps. Distance uses the Haversine great-circle formula. The dataset's population layer covers 33,169 ZCTAs with Census population data (~330 million residents total). (The list covers ZIPs with a Census area (ZCTA); non-ZCTA USPS ZIPs — PO Box, unique-recipient, military — have no Census-tabulated population, so a note reports how many of them fall in the circle rather than listing them.)
Use it for site selection, trade-area analysis, retail catchment estimation, demographic targeting, healthcare planning, real estate due diligence, and feasibility studies. Anywhere you need a population number plus context for a circular area.
Free, no sign-up. Each search runs on our server.
What this tool measures
Population within radius answers the question: "how many people live within X miles of this point?" — and goes beyond a single number to give you the full demographic picture of that area. Total population, density, median income, median age, home values, rent, education levels, poverty rate, commute time, plus the top counties and postal places inside the circle.
Under the hood, the tool sums every US ZIP Code Tabulation Area (ZCTA) whose centroid falls inside your radius and computes population-weighted averages of the underlying US Census American Community Survey data. The result is free, instant, and requires no sign-up.
This is the kind of analysis that powers retail site selection, healthcare catchment planning, real estate due diligence, marketing trade-area sizing, and feasibility studies. Anywhere you need to size and characterize a circular geography around a point.
How to use this tool
Common search examples
Real numbers from this tool, useful as a sanity check before you run your own search. Income figures are population-weighted median household income.
| Center | State | Radius | Population | Density | Median Income |
|---|---|---|---|---|---|
| New York | NY | 10 mi | 7.3M | 23K/mi² | $89K |
| Los Angeles | CA | 10 mi | 3.5M | 11K/mi² | $79K |
| Chicago | IL | 10 mi | 2.9M | 9.1K/mi² | $80K |
| Houston | TX | 15 mi | 2.7M | 3.9K/mi² | $70K |
| Phoenix | AZ | 15 mi | 2.3M | 3.3K/mi² | $79K |
| Atlanta | GA | 15 mi | 2.0M | 2.8K/mi² | $86K |
| Dallas | TX | 15 mi | 2.5M | 3.5K/mi² | $79K |
| Boston | MA | 10 mi | 1.8M | 5.8K/mi² | $118K |
| Seattle | WA | 10 mi | 1.2M | 3.8K/mi² | $133K |
| Denver | CO | 10 mi | 1.4M | 4.4K/mi² | $91K |
Typical population by region type
Population within the same radius varies enormously by region. Every cell below is computed from the same data for a named centre ZIP, at 5-, 25-, and 50-mile radii.
| Region type | Centre ZIP | 5 mi | 25 mi | 50 mi |
|---|---|---|---|---|
| Dense urban | New York, NY (10001) | 2.6M | 14.5M | 19.6M |
| Major metro | Chicago, IL (60601) | 719K | 5.6M | 9.3M |
| Mid-size city | Tulsa, OK (74103) | 133K | 897K | 1.2M |
| Small town | Bend, OR (97701) | 43K | 180K | 258K |
| Rural / frontier | Ely, NV (89301) | 7K | 8K | 9K |
Who uses population-within-radius
1. Retail site selection
Retailers picking new store locations need to know how many people live within a realistic drive of each candidate site, plus their income and household characteristics. A typical big-box retailer wants 100K+ residents within 5 miles and median household income above a target threshold.
2. Healthcare catchment planning
Hospitals, urgent-care chains, and specialist clinics use radius population to estimate patient volume and plan facility expansions. CMS programs, certificate of need filings, and insurance contracts often require ZIP-coded reporting of primary service areas.
3. Real estate due diligence
Investors evaluating apartment complexes, retail centers, or office parks pull radius population and demographics as part of standard underwriting. The home value, rent, and home ownership figures provide quick context on the local housing market.
4. Marketing trade-area sizing
Marketers estimate addressable audience for billboards, local TV ads, and geo-targeted digital campaigns by pulling radius population around each location. The county breakdown maps onto designated marketing areas (DMAs) for media buys.
5. Feasibility studies and grant applications
Nonprofits and economic development agencies need defensible population numbers for grant applications, feasibility studies, and impact reports. The CSV export provides ZIP-level documentation of how the figure was computed.
6. Franchise and dealership planning
Franchisors and OEMs allocate exclusive territories based on population thresholds. A typical car dealership needs 200K residents in a 15-mile radius to justify the investment; a fast-food franchise might need 25K in a 3-mile radius.
7. School district and education planning
Charter schools and private school chains use radius population to estimate student pipeline. Combined with median income and education metrics, it helps decide which neighborhoods can support tuition or where to focus outreach.
8. Insurance underwriting and risk modeling
Insurance carriers use population density and demographics to model exposure inside a radius (think hurricane catastrophe modeling, wildfire WUI exposure, etc.). The numbers feed reinsurance treaties and rate filings.
Methodology
Population calculation
For each search, the tool iterates through every US ZIP in the SimpleMaps dataset, computes the great-circle (Haversine) distance from your center point to the ZIP's geometric centroid (the GIS centroid of the ZIP Code Tabulation Area), and includes the ZIP if that distance is ≤ your radius. Total population is the sum of populations of every included ZIP.
pop_total = Σ pop_i for all ZIPs i where d(center, zip_i) ≤ R d = Haversine great-circle distance (Earth radius 3959 mi) R = your selected radius
Population-weighted demographics
Median income, median age, home value, college rate, and similar metrics are computed as population-weighted averages across the included ZIPs. A ZIP of 50,000 people contributes 10× more to the result than a ZIP of 5,000.
metric_avg = Σ (metric_i · pop_i) / Σ pop_i
Weighting by population is more honest than a simple unweighted average, which would let a tiny ZIP of 100 residents count as much as a metro of millions. Note that a population-weighted average of ZIP medians is an approximation, not a true median of the underlying households.
Density
Population density is total population ÷ geodesic area of the radius circle (in mi²). The radius circle is rendered as a true geodesic polygon using Turf.js (80 vertices), so its area accounts for Earth's curvature.
Limitations & accuracy notes
- Centroid-based inclusion is binary. A ZIP whose centroid is just outside your radius is excluded entirely, even if 49% of its population technically lives inside the circle. Errors are largest for very large rural ZIPs.
- Residential population only. The number is where people sleep, not where they work. Daytime population in dense business districts can be several times higher.
- ACS lag. Census ACS estimates are 1–3 years out of date. For fast-growing or fast-shrinking areas, the actual current population may differ by 5–15%.
- Population-weighted averages have caveats. Median of medians is not a true median. It's a defensible approximation for ZIP-level aggregation but a true area-level median would require microdata that isn't public.
- Straight-line, not drive time. A 30-mile radius circle doesn't account for mountains, water, or road networks. Use a drive-time isochrone tool for routing or service-time analysis.
- Not a substitute for compliance reporting. Use Census Bureau authoritative sources (data.census.gov) for legal, regulatory, or financial filings.
Glossary
- Population-weighted average
- An average that gives more influence to ZIPs with larger populations. A ZIP of 50,000 people contributes 10× more to the median income figure than a ZIP of 5,000.
- ACS (American Community Survey)
- The annual rolling US Census Bureau survey that produces the population, income, education, and housing estimates used by this tool. 1-year ACS releases come out each fall, 5-year combined releases each December.
- ZCTA
- ZIP Code Tabulation Area — Census polygons used to aggregate ACS data at the ZIP level. Most "ZIP code population" numbers in the US actually refer to ZCTAs.
- Population density
- People per square mile. Computed here as total population inside the radius ÷ the geodesic area of the radius circle.
- Trade area
- The geographic area from which a business draws most of its customers. Often defined as a radius around a store, with population and income used to estimate revenue potential.
- Catchment area
- A healthcare or service term for the geographic region served by a facility. Used in hospital network planning, school district analysis, and retail siting.
- Median income
- The household income such that half of households earn less and half earn more. Less skewed by very high earners than mean income, which is why Census uses it.
- Daytime vs nighttime population
- This tool reports residential (nighttime) population — where people sleep. Daytime population (where they work) can be 2–10× larger in dense business districts. Use commercial tools for daytime estimates.
Related tools and resources
For a list of every ZIP code (rather than aggregate stats) within a radius, use Find ZIP Codes in Radius. For a list of cities, use Find Cities in Radius. For drawing circles on a worldwide map without US data attached, use the Map Radius Tool. Browsing by state? Each state has a county directory:
Frequently asked questions
Population, density, household income, age, education, housing, race, and commute data from the SimpleMaps US ZIP Codes Database, derived from US Census Bureau ZIP Code Tabulation Areas (ZCTAs) and the American Community Survey (ACS). 33,169 ZCTAs with Census population data covering ~330 million US residents. Address autocomplete via Photon, reverse geocoding via Nominatim. Distances use the Haversine formula. Maps: MapLibre GL JS + OpenFreeMap tiles + Turf.js for the geodesic radius polygon.
ZIP code data: SimpleMaps US Zip Codes Database v1.95.1 (8 Jul 2026). ZIP lists use the free version (CC BY 4.0); demographics come from the licensed Comprehensive version. Population: American Community Survey 2024 5-year estimates. Coordinates are the geometric centroids of Census ZIP Code Tabulation Areas (2010 ZCTA boundaries).