Property Valuation | RentCast API

The /avm endpoints allow you to retrieve real-time property value and rent estimates for most residential and commercial properties in the United States.

We use a proprietary automated valuation model (AVM) technique when calculating our property value and rent estimates, which has been refined and validated against millions of properties.

You can also use our /avm endpoints to retrieve sales and rental comparables to display in your applications, or calculate your own property value and rent estimates.

How AVMs Are Calculated

Our property value and rent estimates are calculated based on analyzing similar properties listed for sale or for rent near the “subject” property using the following process:

We scan and catalog nearly all sale and rental listings in the US from various public sources. This allows us to maintain an accurate database and “snapshot” of the sale and rental markets in each area
When you make a request for a specific property’s AVM, we find the most similar sale or rental listings near this property that match its type, size, attributes, location, etc.
We use a proprietary weighted average formula to calculate a property value or rent estimate by comparing the subject property with its comparables
We return the estimated property value or rent, the estimate range, a list of comparable listings that were used to calculate it, as well as the subject property information

Since our AVMs are based on property listing data, their data sources and coverage are the same as our /listings endpoints. You can learn more about them right here.

Subject Property Attribute Lookup

Our AVM endpoints can automatically look up subject property attributes (such as the type, bedrooms, bathrooms and living area size) using our property records database.

This behavior can be controlled with the lookupSubjectAttributes boolean query parameter. It defaults to "true" if not provided, which means that our AVM endpoints will attempt to find the subject property attributes before calculating the property value or rent estimates.

In the vast majority of cases, this will significantly improve the AVM accuracy and find more relevant comparables, so we recommend leaving this default behavior unchanged.

You can always provide your own subject property attributes via the propertyType, bedrooms, bathrooms, and squareFootage query parameters. If provided, these values will override any attributes that are looked up automatically.

If you prefer to turn this behavior off and always provide your own subject property attributes, set the lookupSubjectAttributes query parameter to "false" in your requests.

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Automatic subject property attribute lookup requires that you provide the property address using the address query parameter. It will not work if you provide the property location using the latitude/longitude parameters.

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When the lookupSubjectAttributes is set to "true" or omitted, the subject property attributes that were found and used for the AVM calculation will be returned in the subjectProperty response field.

Increasing AVM Accuracy

To maximize the accuracy of the valuation estimates returned by our API, it is important for our AVM endpoints to know the type, bedrooms, bathrooms and living area size of the subject property.

This can be achieved by using one of the following methods:

You can rely on the automatic subject property attribute lookup described above, and allow our API to find these values for you. This should work in the majority of cases, as long as you provide the property address using the address query parameter
You can provide your own values for all subject property attributes using the propertyType, bedrooms, bathrooms and squareFootage query parameters in your requests. This gives you full control over these values if you know them ahead of time

We also provide several optional query parameters that control which comparable listings are selected by our algorithm when calculating valuation estimates.

Omitting these parameters will result in our API using its internal default values, which should produce accurate results in the vast majority of markets.

However, you may be able to further improve the accuracy of returned valuation estimates by overriding them with your preferred values based on local market conditions, past experience or business requirements:

maxRadius: this parameter allows you to set the maximum distance between the comparables and the subject property. Using smaller values can work well in densely populated areas, or when you want our algorithm to only consider hyper-local comps
daysOld: this parameter allows you to set the maximum age of the listings that are selected as comps. When property values or rents are expected to change quickly, using smaller values for this parameter will usually produce more accurate results
compCount: this parameter controls the number of comparable listings that are used when calculating valuation estimates. We generally recommend using larger values for this parameter to increase the pool of comps used by our algorithm

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When using smaller values for the maxRadius or daysOld query parameters, you may receive an error message indicating that there are not enough comps that match your criteria to calculate a valuation estimate. In this case, we recommend gradually increasing their values until a valuation estimate is returned by our API.

AVMs for Multi-Family Properties

When retrieving valuation estimates for multi-family properties (Multi-Family or Apartment property types), it is important to understand the difference between how these properties are handled by the value and rent estimate endpoints:

The value estimate endpoint (/avm/value) will return a value estimate for the entire multi-family or apartment building. When providing subject property attribute parameters in your requests (ex. bedrooms, bathrooms, squareFootage), you should provide the total values for the entire building
The rent estimate endpoint (/avm/rent/long-term) will return a rent estimate for a single unit, not the entire multi-family or apartment building. When providing subject property attribute parameters in your requests (ex. bedrooms, bathrooms, squareFootage), you should provide values for a single unit that you'd like to get a rent estimate for

AVM Values: API vs. RentCast Website

You may notice differences in the rent estimates if you're comparing responses from our rent estimate endpoint (/avm/rent/long-term) and the values you see on the RentCast website.

These differences are most commonly caused by using different API query parameters than the inputs on our website. Here is what you should provide for the query parameters when making your API requests to get similar results to what you see online:

address: provide the full property address, which should match what you enter on our website
propertyType: provide the property type, which should match what you select in the respective dropdown on our website
bedrooms: provide the number of bedrooms in the property, which should match what you select in the respective dropdown on our website
bathrooms: provide the number of bathrooms in the property, which should match what you select in the respective dropdown on our website
squareFootage: provide the total living area size of the property, which should match what you enter on our website
maxRadius: provide a comparable search radius, which should match what you enter on our website in the Search radius input. If you do not have a RentCast Pro subscription (which enables you to change comparable settings on our website), provide 5 as the value
daysOld: provide a comparable look back period, which should match what you enter on our website in the Look back period input. If you do not have a RentCast Pro subscription (which enables you to change comparable settings on our website), provide 270 as the value
compCount: provide 20 as the value, as that is what our website uses internally

When you've verified that the query parameters you provide to our API match the inputs on our website, you should get property rent estimates via the API that are very close to what you see online.

While this is a good starting point, we encourage you to experiment with different values for the maxRadius and daysOld parameters to find what works best for your use cases, markets or specific business requirements.

AVM Responses

Each AVM response will contain the value or rent estimate, the estimate range, a list of comparable sale or rental listings, as well as the subject property information.

In addition to the standard property address, location and attribute fields, each comparable listing record will also include the following:

status: the current listing status of the comparable property
price: the listed price or rent of the comparable property
listingType: the type of the comparable property listing
listedDate: the date the comparable property was most recently listed for sale or rent
removedDate: the date the comparable property listing was removed from the market
lastSeenDate: the date the comparable property listing was last seen as active
daysOnMarket: the number of days the comparable property listing was active on the market
distance: the distance between the comparable property and the subject property, in miles
daysOld: the number of days since the comparable property listing was last seen as active, indicating the "age" of the comparable property
correlation: a ratio indicating how similar the comparable property is to the subject property. This ratio ranges from close to 0 (0% similarity) to 1 (100% similarity)

View the full property valuation schema to learn more about the returned fields and their possible values.

Below is an example of a property value estimate response returned by our API:

{
  "price": 250000,
  "priceRangeLow": 195000,
  "priceRangeHigh": 304000,
  "subjectProperty": {
    "id": "5500-Grand-Lake-Dr,-San-Antonio,-TX-78244",
    "formattedAddress": "5500 Grand Lake Dr, San Antonio, TX 78244",
    "addressLine1": "5500 Grand Lake Dr",
    "addressLine2": null,
    "city": "San Antonio",
    "state": "TX",
    "stateFips": "48",
    "zipCode": "78244",
    "county": "Bexar",
    "countyFips": "029",
    "latitude": 29.476011,
    "longitude": -98.351454,
    "propertyType": "Single Family",
    "bedrooms": 3,
    "bathrooms": 2,
    "squareFootage": 1878,
    "lotSize": 8843,
    "yearBuilt": 1973,
    "lastSaleDate": "2024-11-18T00:00:00.000Z",
    "lastSalePrice": 270000
  },
  "comparables": [
    {
      "id": "5207-Pine-Lake-Dr,-San-Antonio,-TX-78244",
      "formattedAddress": "5207 Pine Lake Dr, San Antonio, TX 78244",
      "addressLine1": "5207 Pine Lake Dr",
      "addressLine2": null,
      "city": "San Antonio",
      "state": "TX",
      "stateFips": "48",
      "zipCode": "78244",
      "county": "Bexar",
      "countyFips": "029",
      "latitude": 29.47046,
      "longitude": -98.351561,
      "propertyType": "Single Family",
      "bedrooms": 3,
      "bathrooms": 2,
      "squareFootage": 1895,
      "lotSize": 6882,
      "yearBuilt": 1988,
      "status": "Active",
      "price": 289444,
      "listingType": "Standard",
      "listedDate": "2025-04-11T00:00:00.000Z",
      "removedDate": null,
      "lastSeenDate": "2025-09-03T10:57:39.532Z",
      "daysOnMarket": 146,
      "distance": 0.384,
      "daysOld": 1,
      "correlation": 0.9916
    },
    {
      "id": "6707-Lake-Cliff-St,-San-Antonio,-TX-78244",
      "formattedAddress": "6707 Lake Cliff St, San Antonio, TX 78244",
      "addressLine1": "6707 Lake Cliff St",
      "addressLine2": null,
      "city": "San Antonio",
      "state": "TX",
      "stateFips": "48",
      "zipCode": "78244",
      "county": "Bexar",
      "countyFips": "029",
      "latitude": 29.47617,
      "longitude": -98.356908,
      "propertyType": "Single Family",
      "bedrooms": 3,
      "bathrooms": 2,
      "squareFootage": 1811,
      "lotSize": 8146,
      "yearBuilt": 1977,
      "status": "Inactive",
      "price": 279000,
      "listingType": "Standard",
      "listedDate": "2025-06-06T00:00:00.000Z",
      "removedDate": "2025-07-12T00:00:00.000Z",
      "lastSeenDate": "2025-07-11T13:21:20.968Z",
      "daysOnMarket": 36,
      "distance": 0.3286,
      "daysOld": 55,
      "correlation": 0.9887
    },
    {
      "id": "6917-Deep-Lake-Dr,-San-Antonio,-TX-78244",
      "formattedAddress": "6917 Deep Lake Dr, San Antonio, TX 78244",
      "addressLine1": "6917 Deep Lake Dr",
      "addressLine2": null,
      "city": "San Antonio",
      "state": "TX",
      "stateFips": "48",
      "zipCode": "78244",
      "county": "Bexar",
      "countyFips": "029",
      "latitude": 29.479375,
      "longitude": -98.351978,
      "propertyType": "Single Family",
      "bedrooms": 3,
      "bathrooms": 2,
      "squareFootage": 1753,
      "lotSize": 11151,
      "yearBuilt": 1974,
      "status": "Inactive",
      "price": 199900,
      "listingType": "Standard",
      "listedDate": "2025-05-22T00:00:00.000Z",
      "removedDate": "2025-08-27T00:00:00.000Z",
      "lastSeenDate": "2025-08-26T12:36:31.859Z",
      "daysOnMarket": 97,
      "distance": 0.2348,
      "daysOld": 9,
      "correlation": 0.9863
    },
    {
      "id": "5314-Lost-Tree,-San-Antonio,-TX-78244",
      "formattedAddress": "5314 Lost Tree, San Antonio, TX 78244",
      "addressLine1": "5314 Lost Tree",
      "addressLine2": null,
      "city": "San Antonio",
      "state": "TX",
      "stateFips": "48",
      "zipCode": "78244",
      "county": "Bexar",
      "countyFips": "029",
      "latitude": 29.477064,
      "longitude": -98.343686,
      "propertyType": "Single Family",
      "bedrooms": 3,
      "bathrooms": 2,
      "squareFootage": 1948,
      "lotSize": 9017,
      "yearBuilt": 2000,
      "status": "Inactive",
      "price": 159900,
      "listingType": "Standard",
      "listedDate": "2025-06-23T00:00:00.000Z",
      "removedDate": "2025-06-28T00:00:00.000Z",
      "lastSeenDate": "2025-06-27T11:02:28.080Z",
      "daysOnMarket": 5,
      "distance": 0.4734,
      "daysOld": 69,
      "correlation": 0.9859
    },
    {
      "id": "7207-Solar-Eclipse,-Converse,-TX-78109",
      "formattedAddress": "7207 Solar Eclipse, Converse, TX 78109",
      "addressLine1": "7207 Solar Eclipse",
      "addressLine2": null,
      "city": "Converse",
      "state": "TX",
      "stateFips": "48",
      "zipCode": "78109",
      "county": "Bexar",
      "countyFips": "029",
      "latitude": 29.463689,
      "longitude": -98.348663,
      "propertyType": "Single Family",
      "bedrooms": 3,
      "bathrooms": 2,
      "squareFootage": 1883,
      "lotSize": 5140,
      "yearBuilt": 2022,
      "status": "Active",
      "price": 320000,
      "listingType": "Standard",
      "listedDate": "2025-03-10T00:00:00.000Z",
      "removedDate": null,
      "lastSeenDate": "2025-09-03T10:33:44.607Z",
      "daysOnMarket": 178,
      "distance": 0.8687,
      "daysOld": 1,
      "correlation": 0.9835
    }
  ]
}

Below is an example of a property rent estimate response returned by our API:

{
  "rent": 1620,
  "rentRangeLow": 1550,
  "rentRangeHigh": 1690,
  "subjectProperty": {
    "id": "5500-Grand-Lake-Dr,-San-Antonio,-TX-78244",
    "formattedAddress": "5500 Grand Lake Dr, San Antonio, TX 78244",
    "addressLine1": "5500 Grand Lake Dr",
    "addressLine2": null,
    "city": "San Antonio",
    "state": "TX",
    "stateFips": "48",
    "zipCode": "78244",
    "county": "Bexar",
    "countyFips": "029",
    "latitude": 29.476011,
    "longitude": -98.351454,
    "propertyType": "Single Family",
    "bedrooms": 3,
    "bathrooms": 2,
    "squareFootage": 1878,
    "lotSize": 8843,
    "yearBuilt": 1973,
    "lastSaleDate": "2024-11-18T00:00:00.000Z",
    "lastSalePrice": 270000
  },
  "comparables": [
    {
      "id": "7306-Kingsland-Dr,-San-Antonio,-TX-78244",
      "formattedAddress": "7306 Kingsland Dr, San Antonio, TX 78244",
      "addressLine1": "7306 Kingsland Dr",
      "addressLine2": null,
      "city": "San Antonio",
      "state": "TX",
      "stateFips": "48",
      "zipCode": "78244",
      "county": "Bexar",
      "countyFips": "029",
      "latitude": 29.473782,
      "longitude": -98.344684,
      "propertyType": "Single Family",
      "bedrooms": 3,
      "bathrooms": 2,
      "squareFootage": 1835,
      "lotSize": 7405,
      "yearBuilt": 1997,
      "status": "Inactive",
      "price": 1627,
      "listingType": "Standard",
      "listedDate": "2025-02-06T00:00:00.000Z",
      "removedDate": "2025-02-07T00:00:00.000Z",
      "lastSeenDate": "2025-02-06T05:09:03.727Z",
      "daysOnMarket": 1,
      "distance": 0.4359,
      "daysOld": 210,
      "correlation": 0.9873
    },
    {
      "id": "4907-Lakebend-East-Dr,-San-Antonio,-TX-78244",
      "formattedAddress": "4907 Lakebend East Dr, San Antonio, TX 78244",
      "addressLine1": "4907 Lakebend East Dr",
      "addressLine2": null,
      "city": "San Antonio",
      "state": "TX",
      "stateFips": "48",
      "zipCode": "78244",
      "county": "Bexar",
      "countyFips": "029",
      "latitude": 29.471408,
      "longitude": -98.348191,
      "propertyType": "Single Family",
      "bedrooms": 3,
      "bathrooms": 2,
      "squareFootage": 1764,
      "lotSize": 6098,
      "yearBuilt": 1996,
      "status": "Inactive",
      "price": 1500,
      "listingType": "Standard",
      "listedDate": "2024-07-11T00:00:00.000Z",
      "removedDate": "2025-02-06T00:00:00.000Z",
      "lastSeenDate": "2025-02-05T05:12:02.891Z",
      "daysOnMarket": 210,
      "distance": 0.3741,
      "daysOld": 211,
      "correlation": 0.9792
    },
    {
      "id": "7037-Lynn-Lake-Dr,-San-Antonio,-TX-78244",
      "formattedAddress": "7037 Lynn Lake Dr, San Antonio, TX 78244",
      "addressLine1": "7037 Lynn Lake Dr",
      "addressLine2": null,
      "city": "San Antonio",
      "state": "TX",
      "stateFips": "48",
      "zipCode": "78244",
      "county": "Bexar",
      "countyFips": "029",
      "latitude": 29.473394,
      "longitude": -98.348222,
      "propertyType": "Single Family",
      "bedrooms": 3,
      "bathrooms": 2.5,
      "squareFootage": 1863,
      "lotSize": 5358,
      "yearBuilt": 1999,
      "status": "Active",
      "price": 1700,
      "listingType": "Standard",
      "listedDate": "2025-08-12T00:00:00.000Z",
      "removedDate": null,
      "lastSeenDate": "2025-09-03T02:50:19.961Z",
      "daysOnMarket": 23,
      "distance": 0.2658,
      "daysOld": 1,
      "correlation": 0.9702
    },
    {
      "id": "5106-Lakebend-East-Dr,-San-Antonio,-TX-78244",
      "formattedAddress": "5106 Lakebend East Dr, San Antonio, TX 78244",
      "addressLine1": "5106 Lakebend East Dr",
      "addressLine2": null,
      "city": "San Antonio",
      "state": "TX",
      "stateFips": "48",
      "zipCode": "78244",
      "county": "Bexar",
      "countyFips": "029",
      "latitude": 29.473168,
      "longitude": -98.349176,
      "propertyType": "Single Family",
      "bedrooms": 3,
      "bathrooms": 2,
      "squareFootage": 1667,
      "lotSize": 6882,
      "yearBuilt": 1987,
      "status": "Inactive",
      "price": 1695,
      "listingType": "Standard",
      "listedDate": "2023-08-25T00:00:00.000Z",
      "removedDate": "2025-05-14T00:00:00.000Z",
      "lastSeenDate": "2025-05-13T04:51:16.590Z",
      "daysOnMarket": 628,
      "distance": 0.2398,
      "daysOld": 114,
      "correlation": 0.9692
    },
    {
      "id": "7323-Kingsland,-San-Antonio,-TX-78244",
      "formattedAddress": "7323 Kingsland, San Antonio, TX 78244",
      "addressLine1": "7323 Kingsland",
      "addressLine2": null,
      "city": "San Antonio",
      "state": "TX",
      "stateFips": "48",
      "zipCode": "78244",
      "county": "Bexar",
      "countyFips": "029",
      "latitude": 29.474238,
      "longitude": -98.34394,
      "propertyType": "Single Family",
      "bedrooms": 3,
      "bathrooms": 2,
      "squareFootage": 1671,
      "lotSize": 9017,
      "yearBuilt": 2001,
      "status": "Inactive",
      "price": 1575,
      "listingType": "Standard",
      "listedDate": "2024-12-30T00:00:00.000Z",
      "removedDate": "2025-06-05T00:00:00.000Z",
      "lastSeenDate": "2025-06-04T04:32:03.650Z",
      "daysOnMarket": 157,
      "distance": 0.4688,
      "daysOld": 92,
      "correlation": 0.9663
    }
  ]
}

Available Endpoints

The following endpoints are available for retrieving property value and rent estimates:

/avm/value: an endpoint for retrieving current property value estimates, which represent the current market value, or after-repair value (ARV), of a given property. It also returns a list of comparable sale listings for that property
/avm/rent/long-term: an endpoint for retrieving current long-term property rent estimates for a given property. It also returns a list of comparable rental listings for that property