Enter the total square footage of the addition and the property’s value per square foot to determine the ADU cost.

## ADU Cost Formula

The following formula is used to calculate the cost of an ADU.

ADUc = A * PV * .85

- Where ADUc is the cost of the addition dwelling unit ($)
- A is the total square footage of the addition (ft^2)
- PV is the price per square foot value of the property ($/ft^2)

## What is an ADU Cost?

Definition:

An ADU cost is defined as the total cost to construct an accessory dwelling unit. These units are built on single-family lots but are separate from the main house.

The cost of these units is typically 85% of the per square foot value of the property.

For example, if the property had a value of $100 per square foot, then the ADU cost would be $85 per square foot.

## How to calculate ADU cost?

Example Problem:

The following example problem outlines how to estimate the cost of an ADU.

First, determine the value of the property on a square foot basis. In this example, the property has a value of $500 /ft^2.

Next, determine the size of the ADU. This ADU will have a total size of 300 square feet (ft^2).

Finally, calculate the ADU cost using the formal above:

ADUc = A * PV * .85

ADUc = 300 * 500 * .85

ADUc = $127,500.00