What Is an APN Number?

APN numbers crop up often in the real estate world. Agents and property tax professionals use them to uncover financial and legal details about a plot of land. Homebuyers and -sellers also encounter APNs in their paperwork, though they sometimes miss the reference—APNs have many different names.

So, what is an APN number? It stands for Assessor Parcel Number or Assessor’s Parcel Number, a series of digits assigned to a plot of land. And it’s one of the most important numbers in real property.

APN number: What is it?

An APN number gives the exact location of property. (Technically, the term “APN number” is redundant, since the word “number” is in the acronym. It’s like referring to a PIN number, or a “personal identification number number.”)

Redundant or not, however, APNs are everywhere—though they look different depending on where you go. That’s because towns and cities use different numbering systems.

Sacramento County, California, for example, uses 14-digit APNs to identify almost 475,000 land parcels, according to the county assessor’s office. Nearby Fresno County relies on just eight digits, but adds letters to convey special information.

Municipalities often use letters to describe special circumstances related to property use and ownership. In Fresno County, for example:

• “S” means “surface rights only.” It indicates that the property owner doesn’t have rights to the gravel, stone and other geological material under the land’s surface.
• “M” means “mineral rights.” It indicates that the property owner can sell the minerals their land is built on.
• “P” means “possessory interest.” It’s used when someone has an interest in publicly owned land and that interest is taxable.

Different towns and cities use different codes. Check the official guide or ask the local property tax assessor if you’re unsure.

What is an APN used for?

APNs are useful any time a property owner, tax professional or real estate professional needs to precisely identify a land parcel.

Property tax calculations

“Appraisers will often use APNs in the process of figuring out property taxes,” said Frank DiZenzo, a CPA and cofounder of real estate technology company Ownwell in Austin, Texas. “APNs are usually the quickest and most precise piece of information to use to find property tax-related information in an assessor’s system. Street addresses are actually far less reliable.”

That’s because, according to DiZenzo, assessors often have to change property addresses. If the owner misses that notification, the property can transfer hands under the wrong address.

Someone who researches that property by address would find inaccurate information. That’s why transactions routinely list APNs and legal descriptions along with street addresses.

Budgeting and planning

But APNs aren’t just for appraisers. Property owners who need tax information for budgeting or planning purposes can search local records by APN. It’s the best way to find current and past bills, DiZenzo said.

APNs also help buyers and sellers figure out tax responsibilities. At closing, parties usually prorate property taxes. The part of the tax year before the closing date is the buyer’s responsibility. Everything after that is the seller’s. A search by APN helps buyers, sellers and agents determine each party’s share.

Tracking property changes

When property owners decide to split or combine parcels, APNs reflect those changes.

“For example, a property owner might buy two or more separate but adjacent parcels with the goal of developing them as a single property,” said DiZenzo. Or, “a developer may buy a larger parcel of vacant land and divide it into multiple parcels to construct new homes, then sell the new parcels individually. Each of the new smaller parcels will have their own new APN.”

APNs offer the most current information about a property. This helps lawyers, accountants and sales agents provide accurate advice.

Boundary disputes

According to David Reischer, a New York City real estate attorney and CEO of LegalAdvice.com, current APNs may help resolve boundary disputes. Using APNs, attorneys learn how the municipality treats abutting parcels for tax purposes. If there is a contrary claim, the attorney can point to that information.

However, Reischer pointed out, not all US jurisdictions accept property maps as evidence in boundary claims. Contact an attorney in your area if you have questions.

How to find a property APN

If you own property, you can usually find your APN on your property tax bill. Assessors will often print it at the top of the bill, near the property owner’s name and address. Contact your lender if you don’t receive a copy of the bill.

If you do have a bill, look for groups of three to four numbers, separated by dashes.

Sacramento County uses the example “006-0153-011-0000.” In a location with a shorter sequence, it might look like an APN in Fresno: “466-160-01T.”

You can also find a parcel’s APN through your area’s tax assessor’s office. This may be a county or municipal position, depending on your state of residence.

The quickest way to find your area’s tax assessor is through Google. Search for your town’s or city’s name followed by “property tax assessor.”

Look for an official .gov website. Keep in mind some counties and municipalities have different titles for their assessor offices. San Diego has an assessor/recorder. Chicago has a county assessor’s office.

When you find the assessor’s website, look for a property search tool. These often bring up the property’s APN. If those options fail, call the office and ask for the property’s APN.

Should you need help, you can always ask a real estate attorney or related professional. Keep in mind you’ll usually have to pay a fee for any help the professional offers unless you’re already using their services.

Who assigns an APN?

A county tax assessor assigns new APNs based on the local numbering system. Each system describes the property’s location in the local map book. Fresno and Sacramento publish two of the country’s most thorough APN guides. They explain their similar systems this way:

• The first group of digits identifies the map book where the parcel appears.
• The next grouping indicates page number.
• The following digits identify the block where the parcel is located.
• The final numbers identify the specific parcel.

According to attorney David Reischer, municipalities vary in how they identify new parcels. The best way to get more details on this process is to contact your local tax assessor.

Other names for an APN

Real estate professionals may call an APN by other names. The most common include:

• Property Identification Number (PID)
• Assessor’s Identification Number (AIN)
• Property Account Number
• Tax Account Number
• Sidwell Number

Like numbering conventions, term choice can vary by location.

APNs guide you to the answers

APNs provide clarification in many situations, from property tax planning to disputes between neighbors. Knowing your property’s APN points you to the most official and accurate information. With it, you can settle those issues faster and avoid confusion.