An Accessory Dwelling Unit (ADU) is a secondary housing unit built on the same lot as a primary residence. Whether you're planning a basic, standard, or premium ADU, knowing the estimated cost in advance can help you make informed financial decisions. Our ADU Cost Calculator allows you to estimate the total cost based on:

• ADU Size (sqft)
• Construction Type (Basic, Standard, or Premium)
• Additional Features (Kitchen, Bathroom, and Heating/Cooling)

This blog will guide you through the calculation process, including the formula used in our calculator and an example calculation.

ADU Cost Calculation Formula

Step 1: Base Cost Calculation

The base cost is calculated based on the ADU size and the selected construction type:

$\text{Base Cost} = \text{ADU Size} \times \text{Cost per Square Foot}$

The cost per square foot varies depending on the construction type:

• Basic Construction: $150 per sqft
• Standard Construction: $200 per sqft
• Premium Construction: $300 per sqft

Step 2: Adding Additional Features

If additional features are included, their respective costs are added:

$\text{Total Cost} = \text{Base Cost} + \text{Kitchen Cost} + \text{Bathroom Cost} + \text{Heating/Cooling Cost}$

The additional feature costs are:

• Kitchen: $10,000
• Bathroom: $5,000
• Heating/Cooling: $7,000

Example: Calculating the Total ADU Cost

Let’s calculate the total cost of building an ADU with the following specifications:

• Size: 600 square feet
• Construction Type: Standard ($200 per square foot)
• Additional Features: Kitchen, Bathroom, Heating/Cooling

Step 1: Calculate Base Cost

$\text{Base Cost} = 600 \times 200 = 120,000$

Step 2: Calculate Additional Feature Costs

• Kitchen: $10,000
• Bathroom: $5,000
• Heating/Cooling: $7,000

$\text{Feature Cost} = 10,000 + 5,000 + 7,000 = 22,000$

Step 3: Calculate Total Cost

$\text{Total Cost} = 120,000 + 22,000 = 142,000$

Conclusion

The total cost to build a 600 square foot ADU with standard construction, a kitchen, bathroom, and heating/cooling system would be $142,000. By using the ADU Cost Calculator, you can easily estimate the cost based on different sizes, construction types, and additional features, allowing you to plan your ADU project effectively.