A home insurance rebuild cost calculator estimates the cost of reconstructing your property, which is different from its market value. It may consider details such as the property’s size, age, construction type and location, while the rebuild figure can also include demolition, site clearance and professional fees. Free online calculators can provide a useful starting point, but unusual, listed or high-value homes may need a professional assessment. Check the result with your insurer or an FCA-authorised provider and review the sum insured regularly, particularly after alterations or extensions.