Home Value Estimate
If you are interested in learning the current value of your home, the quickest and easiest method is to look it up on Zillow. While the values Zillow provides are not always accurate, it's a starting point.
You also might consider asking a local real estate broker for an opinion (commonly called a Brokers Price Opinion or "BPO"), although you may be charged for this service.
You can hire a real estate appraiser to formally appraise your property. This service usually costs several hundred dollars, but it is considered the most accurate method of estimating property value short of actually selling on the open market. Note that if you apply for a refinance loan your lender must order an independent appraisal. The lender will not be allowed to use an appraisal report that you ordered for yourself.
All of these methods rely mainly on the "market" approach to estimating value. This means that value is determined by considering the prices recently paid for a representative sampling of homes comparable to your property.