How to Track ROI on Letterbox Drops: The Complete Guide

Gibson has been in the letterbox distribution business for over 20 years. And the question we 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 is not measurement. That is hope.

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

Why cannot most businesses measure letterbox ROI?

The problem is simple: if you put the same phone number on your flyer that is 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 do not know. So you either keep spending on letterbox drops and hope they are working, or you cut them because you cannot prove they are not a waste.

Both of those are bad decisions made without data.

The fix: tracked numbers plus cell-tower geo on every mobile call

Here is what we do differently. Instead of putting your regular business number on the flyer, we use a tracked phone number. Every call to that number is logged with caller ID, duration, time, and (for mobile callers) the cell tower that routed the call. Cell-tower routing tells us the suburb the caller was in when they dialled.

For most medium operators with a local footprint, 2-3 tracked numbers is enough to cover all attribution: one for the letterbox flyer, one for the website (via Dynamic Number Insertion so paid traffic shows a different number to organic), and one for paid ads. The cell-tower data on every mobile call gives you the suburb breakdown without needing a separate number for every postcode.

For high-volume campaigns that need tight split-testing across suburbs (an automotive network running 30+ catchments, an enterprise real estate group testing format-by-suburb), we scale the number setup so each suburb or each format gets its own line. Most operators do not need that overhead.

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+ Sydney suburbs across four directly-operated regions (Sydney CBD, St George, Eastern Suburbs, Inner West). Sutherland Shire and selected outer-Sydney areas are delivered via a partner crew.

2. Set up tracked numbers

Most operators run 2-3 tracked numbers. The flyer gets a clean Australian number (02 landline or 1300/1800), DNI on the website swaps the number based on visitor source, and paid ads carry their own line. All three ring through to your office exactly the same way. The caller sees a normal local number and dials it.

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 have been doing this since 2006 and we know which suburbs respond and which do not.

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 are 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 does not depend on cookies or third-party platforms.

Why does not anyone else do this?

Most letterbox distribution companies are logistics businesses. They print, they walk, they deliver. Measurement is not their thing.

And most call tracking companies do not do letterbox distribution. They track digital channels: websites, Google Ads, social. If you are weighing up whether to run letterbox at all versus putting that budget into social media, read our comparison of letterbox vs social media for Sydney SMBs. The results often surprise people.

We do both. Gibson Promotions combines supervisor-verified Sydney letterbox distribution with tracked-call attribution, including cell-tower geo data on every mobile call. We have 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 cannot deliver: measurable letterbox marketing without the overhead of a number per postcode.

Real numbers from real campaigns

We have 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 is 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 would need to run the same campaign for months before they had enough of a “feeling” about what worked.

Getting started

If you are 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 audit and we will 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.

Letterbox distribution Sydney, made measurable

This is what separates Gibson from a blind drop. Letterbox distribution Sydney, flyer distribution Sydney and leaflet distribution Sydney all run with a tracked number on the artwork, so every letterbox drop and letterbox drop Sydney run reports calls per suburb. Letterbox delivery is photo-verified, flyer printing Sydney and brochure printing Sydney sit in the same shop, and the same tracking measures broader print marketing, letterbox marketing and direct mail Australia campaigns.

Frequently asked questions