Radio and audio advertising runs on precision. A 30-second spot is exactly 30 seconds — not 32, not 28. That means your script has to be exactly the right length before it ever goes to the studio. Get the word count wrong and you’re either cutting on the fly in the booth or paying for extra studio time.
This guide gives you the exact word counts for every standard radio ad format, explains what affects timing, and shows you how to check your script before you ever book a session.
Why Radio Ad Timing Is Non-Negotiable
In broadcast, time is literally money. Radio stations sell ad inventory in fixed windows: 15, 30, 45, and 60 seconds. If your spot runs long, it either gets cut off mid-sentence or bumps into the next piece of programming. If it runs short, you’ve wasted paid air time and your call to action sounds rushed.
Beyond station requirements, tight timing makes for better advertising. The discipline of writing exactly to a time slot forces clarity — no fluff, no redundancy, just the message delivered efficiently.
Radio Ad Word Count by Spot Length
These word counts are based on a standard broadcast delivery pace of approximately 160–170 WPM, which is the industry norm for radio commercial voiceover:
15-Second Radio Spot
- Word count: 35–45 words
- What fits: One key message and a call to action. That’s it.
- Common uses: Brand reminders, event announcements, promotional bookends
30-Second Radio Spot
- Word count: 65–85 words
- What fits: A hook, a brief value proposition, and a clear call to action
- Common uses: Most general-purpose retail and service advertising
45-Second Radio Spot
- Word count: 100–125 words
- What fits: A slightly expanded message with one supporting detail
- Common uses: Less common than 30s or 60s, but used in some markets
60-Second Radio Spot
- Word count: 130–165 words
- What fits: A full story arc — setup, problem, solution, and call to action
- Common uses: Campaigns that need more narrative or complex information (legal, medical, financial)
For a precise runtime estimate on your script, use Word Timer’s Radio Script Timer — it’s calibrated specifically for broadcast delivery rates.
What Affects Your Radio Script’s Actual Timing
Word count targets are starting points. Several variables affect the real-world timing of your spot:
Delivery speed of the voice talent. Different voice artists have different natural paces. A script at 75 words might run at :28 with one talent and :31 with another. Always time with your actual talent before finalizing.
Pauses and emphasis. Any deliberate pause — for effect, for a phone number, for a dramatic beat — adds time without adding words. A script that includes a phone number read out loud (“call eight hundred, five five five, twelve twelve”) takes significantly longer than its word count suggests.
Production elements. Music beds that the voice has to talk over, sound effects, or dialogue exchanges all affect pacing and available time for scripted words.
Syllable count, not just word count. “Pharmaceutical” takes longer to say than “drug.” Heavy technical or brand language slows delivery. If your script is loaded with long words, trim to the lower end of the word count range.
Tips for Writing Radio Ad Copy That Works
Lead with the most important thing. Listeners can’t rewind. If your key message is buried in the middle, many will miss it. Put your headline first.
Read it aloud while writing. Radio copy lives in the ear, not on the page. Something that reads cleanly on screen can sound awkward when spoken. Always read your drafts aloud as you write.
Avoid tongue twisters. Alliteration and repeated sounds are a liability in broadcast copy. “Six sleek slim slick silver street signs” may look fine written down and be a disaster in the booth.
Write the phone number or URL last. Contact information always takes longer than its word count suggests. “Visit us at www dot word dash timer dot com” adds time. Budget for it by trimming elsewhere.
Write for one listener. Radio is an intimate medium. Don’t write “listeners” or “customers” — write “you.” The best radio copy sounds like one person talking to one other person.
How to Check Your Radio Script Length Before the Session
The fastest way to confirm your timing before going into the studio is to use a dedicated radio script timer.
Word Timer’s Radio Script Timer is built for exactly this — paste your script, and it gives you an estimated runtime using broadcast-standard delivery rates.
For voiceover projects more broadly, the Voiceover Script Timer covers different delivery styles. For podcast audio, the Podcast Script Timer provides estimates calibrated for conversational delivery.
You can also use the general Word Timer and set your preferred speaking rate manually if your talent runs faster or slower than the broadcast average.
Frequently Asked Questions
How many words is a 30-second radio ad? A standard 30-second radio ad runs 65–85 words at typical broadcast delivery speeds of 160–170 WPM.
How many words is a 60-second radio ad? A 60-second radio spot contains roughly 130–165 words at standard broadcast pace.
How many words is a 15-second spot? A 15-second radio ad is typically 35–45 words — enough for a single focused message and a call to action.
How do I time a radio script? Paste your script into Word Timer’s Radio Script Timer for an instant estimate, then do a timed read-aloud to confirm before your studio session.
What is the standard speaking rate for radio ads? Most broadcast radio copy is delivered at 160–170 WPM. High-energy retail or fast-paced spots can push 180–190 WPM. Informational or legal spots may run closer to 140–150 WPM.