An appraiser is a person who is trained to put a price value on your home or property. A bank will hire an appraisal during mortgage or refinance procedures; so you may have one on record if you have done this recently. You could also hire a home appraiser for an up-to-date appraisal.
An assessed value is what the city/town values your property. An assessment is used to set your property taxes. While both numbers are helpful as a guideline - they don't often match and are often confused. An assessed value is often lower than the appraised value.
Some customers look at the city/town records for recent closings in order to see what similar houses sold for, then they compare that information with their property. You can also look at our web site and other web sites to make some comparisons. It can be helpful to figure out the price per square foot for comparison purposes.
You can also claim your property as the owner on Zillow which allows you to "tweak" what your property is all about. You will then have a more accurate but rough price estimate through Zillow.