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Letterbox·April 2026·5 min read

How to Track ROI on Letterbox Drops: The Complete Guide

Albert Triolo, Managing Director of Gibson Promotions

Albert Triolo

Managing Director, Gibson Promotions · 20 years in marketing accountability

Key takeaways

  • Printing a unique tracked number on each suburb's flyer tells you exactly which areas are generating calls, not just a total.
  • You get a cost-per-call figure per suburb, so you can double down on what works and fix what doesn't.
  • Gibson Promotions is the only Sydney company combining letterbox distribution with call-level tracking per suburb.
  • We cover 155+ suburbs across Sydney and have been doing tracked distributions since 2006.
  • A tradie can know within two weeks which suburb is worth repeating, instead of guessing after months.

I've been in the letterbox distribution business for over 20 years. And the question I hear most often is: “How do I know if my flyers actually worked?”

Fair question. Most businesses drop 10,000 flyers across a handful of suburbs and then wait to see if the phone rings more than usual. That's not measurement. That's hope.

There's a better way. It's a rare pairing in Sydney: letterbox distribution with tracked, per-suburb call data.

Why can't most businesses measure letterbox ROI?

The problem is simple: if you put the same phone number on your flyer that's on your website, your Google listing, your van signage, and your business card, you have no way of knowing which one made the phone ring.

A call comes in. Was it the flyer? Was it Google? Was it a referral from a neighbour? You don't know. So you either keep spending on letterbox drops and hope they're working, or you cut them because you can't prove they're not a waste.

Both of those are bad decisions made without data.

The fix: unique tracked numbers per suburb

Here's what we do differently. Instead of putting your regular business number on the flyer, we assign a unique tracked phone number to each suburb, or even each campaign drop.

  • Hurstville flyer gets number A
  • Kogarah flyer gets number B
  • Cronulla flyer gets number C

All three numbers ring through to your office, exactly the same way. The caller doesn't notice anything different. They just see a local number and dial it.

But on your end, you can see exactly which suburb generated each call.

Step by step: how it works

1. Plan the drop

We work out which suburbs you want to hit, how many households in each, and the timing. We cover 155+ suburbs across Sydney, from the St George area right through to the Inner West, Sutherland Shire, and Eastern Suburbs.

2. Assign tracked numbers

Each suburb (or batch of suburbs) gets its own tracked phone number. These are real Australian numbers: 02 landlines or 1300/1800 numbers. Nothing looks unusual to the person calling.

3. Print and distribute

The flyer goes out with the tracked number printed on it. We handle the distribution using our own team. No random subcontractors dumping flyers in bins. We've been doing this since 2006 and we know which suburbs respond and which don't.

4. Calls come in with attribution

When someone picks up that flyer and calls the number, the call tracking system logs it automatically. You see the suburb, the time, the call duration, and whether it was a new or repeat caller.

5. Compare cost per call by suburb

This is where it gets powerful. After the campaign, you can see:

  • Hurstville: 5,000 flyers dropped, 14 calls, $1.43 per call
  • Kogarah: 3,000 flyers dropped, 3 calls, $4.00 per call
  • Cronulla: 4,000 flyers dropped, 22 calls, $0.73 per call

Now you know. Cronulla is outperforming the others. Next time, maybe you double down on Cronulla and test a different offer in Kogarah. You're making decisions with numbers, not gut feel.

With first-party data becoming more important as digital ad targeting tightens up, tracked phone calls from physical flyers give you a source of attribution data that doesn't depend on cookies or third-party platforms.

Why doesn't anyone else do this?

Most letterbox distribution companies are logistics businesses. They print, they walk, they deliver. Measurement isn't their thing.

And most call tracking companies don't do letterbox distribution. They track digital channels: websites, Google Ads, social.

We do both. Gibson Promotions combines letterbox distribution with call-level tracking per suburb, a pairing that is rare in the Sydney market. We've been distributing flyers across Sydney for 20+ years and running call tracking for over a decade. Those two things together give you something most campaigns can't deliver: measurable letterbox marketing.

Real numbers from real campaigns

We've run tracked letterbox campaigns for trades businesses, real estate agents, dental clinics, and local service providers across Sydney. The clients who measure consistently outperform the ones who guess, because they can see what's working and do more of it.

A tradie dropping flyers across three suburbs with tracking can see within two weeks which suburb is worth repeating. Without tracking, they'd need to run the same campaign for months before they had enough of a “feeling” about what worked.

Getting started

If you're already doing letterbox drops, or thinking about starting, the tracked number setup adds very little to the cost. You get real data from day one instead of waiting months to “see how it goes.”

Want to see how this would work for your specific suburbs? Book a free call auditand we'll map it out for you.

If you want to understand how the tracking technology works under the hood, read our plain-English guide to call tracking.

Frequently asked questions

Can you really measure the ROI of a letterbox drop?

Yes. By printing a unique tracked phone number on each suburb's flyer, you can see exactly how many calls came from each drop. You end up with a cost-per-call figure for every suburb you ran.

How do tracked numbers work on a letterbox flyer?

Instead of your regular business number, the flyer shows a unique Australian number assigned to that suburb or campaign. Calls to that number ring through to your office as normal, but the system records which flyer triggered the call.

Do I need a different number for every suburb?

For best results, yes: one number per suburb. If your budget is tight, you can group nearby suburbs together and use one number per group, then split them out once you have more data to work with.

How many suburbs does Gibson Promotions cover in Sydney?

We cover 155+ suburbs across Sydney, from the St George area through to the Inner West, Sutherland Shire, and Eastern Suburbs.

How quickly will I see results from a tracked letterbox campaign?

Most campaigns start generating calls within a few days of the drop. You typically have enough data within two weeks to see which suburbs are performing and which need a different approach.

Want to see this in action?

Book a free call audit. Albert will show you how this applies to your business specifically.

Get your free call audit