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We read every message. If you got a contractor quote that's way off from our estimate, tell us — that data helps calibrate the model.

We don't share your email with third parties. Read our privacy policy.

Quick answers

How do I report an inaccurate cost estimate?

Use the contact form and include your ZIP code, addition type, and the contractor quote you received. That data directly informs our quarterly updates.

Can I use your data in my own project or article?

Yes, with attribution. Link back to homeadditioncalc.com and note the date the data was retrieved. Our data updates quarterly, so always check for the current version.

Do you take advertising or sponsored content?

We run Google AdSense display ads only. We don't accept sponsored content, paid placements, or affiliate arrangements that could bias our cost estimates.

How quickly do you respond?

We aim to respond within 2 business days. Data correction requests get priority.