Start with the sale side: your home's value minus any remaining mortgage gives your gross equity, then subtract seller closing costs, typically 4 to 6 percent covering commission, legal fees and adjustments together, to get what actually lands in your account at possession.
The next home is the other half of the equation. A smaller home, a condo, or a rental all carry different price tags and different ongoing costs, so the equity you free up is really the gap between what you sell for and what you spend next, not the sale price alone.
Joel Dyck runs this full math with clients using a hand-reviewed valuation of the current home before they commit to a next step. Get your hand-reviewed valuation from Joel Dyck.