What’s Your 20 Mean? CB Radio 10-Codes Explained

What “What’s Your 20” Means

“What’s your 20” is shorthand for 10-20 — the radio code for location. When someone asks it, they’re asking: where are you right now?

The number 20 alone doesn’t mean location. The “10” prefix is what triggers it. 10-20 is one of dozens of 10-codes used across police, CB radio, and emergency services. Each code follows the same format: 10 followed by a number, where the number carries the specific meaning.

You’ll hear it written as “10-20” or spoken as “ten-twenty.” Many people drop the 10 entirely and just say “what’s your 20” — that’s the casual version that stuck in everyday language and pop culture. You’ll also see it as “what’s your 10-20” (keeping the full code) or “what is your 20” in text and casual speech. All three mean exactly the same thing: where are you right now?

Where “What’s Your 20” Came From

The APCO 10-Code System (1937)

The Association of Public-Safety Communications Officials — APCO — created the 10-code system in 1937. Early radio technology was unreliable. Transmissions were short, signals dropped, and clarity was poor.

Police dispatchers needed a way to send complex messages in as few words as possible. A two-part code — 10 plus a number — solved the problem. 10-4 meant acknowledged. 10-20 meant location. 10-7 meant out of service. The whole system fit in your head.

It worked so well it spread fast. Law enforcement agencies across the U.S. adopted it through the 1940s and 1950s, and it became the backbone of radio communication in public safety.

CB Radio and Truckers (1970s)

Civilian CB radio use exploded in the 1970s. The 1973 fuel crisis hit truck drivers hard — speed limits dropped, fuel was rationed, and drivers needed to share road conditions instantly. CB radio became the tool, and trucker lingo became the language.

Truckers borrowed heavily from police 10-codes. “What’s your 20?” became standard on Channel 19 — the de facto trucking channel — because it was fast and unambiguous. Everyone knew what was being asked.

Movies like Smokey and the Bandit (1977) and the hit song “Convoy” pushed CB slang into mainstream American culture. By the late 1970s, CB radio had over 14 million licensed users in the U.S., and “what’s your 20” was part of the national vocabulary.

Police and Emergency Services

Law enforcement still uses 10-codes, though it varies by department. After 9/11, FEMA and the Department of Homeland Security recommended plain language for inter-agency communication — different agencies had different 10-code meanings, and that caused confusion during the emergency response.

But many local police departments kept their systems. And 10-20 — location — is one of the codes that never went away. It’s too useful, too ingrained. You’ll still hear it on police scanners across the country.

The Complete 10-Code Reference Table

These are the standard APCO 10-codes used by truckers and CB users. Some agencies modified the meanings locally, but these are the core definitions that work across CB radio, police, and emergency services.

For the full rundown on walkie-talkie lingo and radio slang — including CB handles, Q-codes, and phonetic alphabet — we’ve got everything in one place.

What Does 10-4 Mean?

If “what’s your 20” is the most-asked question on CB radio, 10-4 is the most-recognized answer in American culture. It means message received and understood. You heard the transmission clearly. No need to repeat. Got it. That single meaning — no regional variation, no ambiguity — is exactly why it crossed from police dispatch into trucking and eventually into everyday speech.

In the original APCO system, 10-4 was assigned to “Acknowledgment — message received.” While some codes shifted meaning between departments, 10-4 stayed consistent nationwide. The FCC Citizens Band Radio guide recognizes it as one of the standard CB operating conventions alongside 10-20 (location) and 10-7 (out of service).

In real CB use, you’ll hear “10-4, what’s your 20?” strung together constantly on Channel 19 — the driver confirms they received the last message and immediately asks for the other trucker’s location. That pairing is the core of CB convoy communication. If you’ve ever said “ten-four, good buddy” without being near a radio, you’ve been speaking trucker longer than you realized.

How “What’s Your 20” Is Used Today

Truckers and CB Radio

Channel 19 is still the most active CB channel on U.S. highways. Long-haul truckers use it to share speed trap locations, accidents, and road closures in real time. And “what’s your 20” is still the fastest way to ask a driver’s current position.

If you’re new to CB radio, you’ll hear it constantly. The response is simple — state your location or a nearby landmark. “Westbound I-40, just passed Flagstaff” is all you need. Don’t overthink it.

Signal range matters more than most people realize when you’re relying on CB for road communication. We break down exactly how far CB signals carry in our CB radio range guide — terrain and antenna setup are the two biggest variables.

Everyday and Casual Use

You don’t need a CB radio to use this phrase anymore. It’s crossed fully into everyday language — parents text it to their kids, friends use it in group chats, and security teams use it on jobsite radios without thinking about the CB origin.

The meaning’s identical in every context: where are you? But the CB heritage gives it a different tone. It’s direct. It implies you need an answer fast, not a paragraph explaining what you’re doing later.

Military and Security

Military radio relies on NATO phonetic protocols and MILSTD formats rather than APCO 10-codes. But 10-codes do appear in National Guard units that cross-train with police, and many private security firms use them for internal radio communication.

If you’re operating two-way radios in a professional context, the radio etiquette guide covers the full protocol — how to key up, how to end a transmission cleanly, and which codes matter most on the job.

How to Respond to “What’s Your 20”

The response is your location — specific enough to be useful, short enough to be clear. You don’t need to repeat the question back or confirm you heard it. Just answer.

On CB radio, the format is direction, highway, and landmark: “Eastbound I-70, mile marker 223.” On a two-way radio at a jobsite, a building name or room number works. In a casual text, a neighborhood or intersection is enough.

And if you’re setting up a radio group that uses FRS or GMRS channels instead of CB, the same 10-code system works across those frequencies too. The FRS and GMRS frequency guide covers channel assignments and what each band is actually good for.

One thing to remember: if someone asks “what’s your 20” and you’re not comfortable sharing your exact location, “I’m mobile” or “en route” is an accepted answer in radio culture. You gave something without giving everything.

That’s the full picture on “what’s your 20” — origin in the 1937 APCO system, truckers adopted it in the 1970s, and it’s now part of everyday English. The 10-code table above covers every code that still matters. If you run a CB setup, work in a radio-equipped environment, or just want to sound fluent on Channel 19 — those codes are worth knowing.

Written by the TechnicalsSolution editorial team. We test two-way radios, CB equipment, and walkie-talkies hands-on. Our guides are built on FCC documentation, manufacturer specs, and real-world radio use — not recycled summaries.