What I've learnt sending 10,000 letters

Did you know that the average response rate for a letter campaign in 2017 was 5.1%? That’s compared to a response rate of 0.6% for email, 0.2% for display, and 0.4% for Social Media. It’s clear therefore, that direct mail blows most other marketing channels out of the water in terms of engagement.

But letter campaigns are hard to get right. They are finicky, expensive things that have the very real possibility of netting zero results. Small mistakes can completely derail your campaign, but information on the subject is relatively thin on the ground compared to email.

Here, I share what I’ve learnt sending 10,000+ letters.

What are the pros and cons of a letter campaign?

Letter campaigns are not for everyone. In-fact, only a small percentage of businesses should think about launching one.

The fact of the matter is, that there are a number disadvantages compared to most other online marketing channels.

Probably the most significant is the difficulty of tracking results.

For this reason it is absolutely vital to include a short, unique URL or coupon code in your letter. This will help you identify the sessions generated by the letter campaign.

Unfortunately, this tracking method is far from perfect. Especially for services which do not lend themselves to coupons and discounts, recording on-site engagement is tough. The vast majority of readers will enter your brand name into Google and go from there. Only very few will take the time to enter a specific URL.

Additionally, you have little-to-no information about how people perceived your letter. What kind of impression did it make? Did the recipient read all the way through? Was there a part that he particularly liked? How can you optimize it going forward?

Whereas tools like Google Analytics and Hotjar give us an incredibly granular view of visitor engagement, much of offline marketing is left up to the imagination.

Finally, it’s worth noting that letter campaigns are expensive. You can expect to pay €0.50-0.80 per domestic letter, and €1.00-1.50 for internationals. Of course, it’s much more if you only calculate those that are actually opened and read.

But that’s enough about the negatives, let’s talk about the positives.

Apart from the excitingly high response rate, letter campaigns work well as an initial touch point in a larger acquisition funnel. Retargeting letter campaigns with ads on Adwords and Facebook yield a 28% higher conversion rate. They also do a much better job at reactivating dormant, existing users than any other channel out there.


  1. High average response rate
  2. Particularly effective as a touch point in a multi-channel acquisition funnel


  1. Very hard to track the results
  2. Relatively expensive

When is a letter campaign the right choice?

With these pros and cons in mind, when does it make sense to send out a letter campaign?

I think the most important thing in this regard, is your customer lifetime value (CLV). If your CLV is below €500 you should avoid sending letters to cold leads. Even if your product has a large ticket size, it will be very tough to get a positive ROI.

If your CLV is below this threshold, I would suggest experimenting with inactive users. If you have their postal address, send a hyper-targeted campaign addressing a specific pain point and offering a discount/coupon.

For those of you with a CLV above €500, direct mail is definitely still in play. The question now becomes: can you generate targeted, high quality leads for your letter campaign?

Getting great contact information

Getting contact information for businesses, including postal addresses, is relatively easy. In most cases, your best bet is your national company house. In most countries, there are company houses/directories like this one, maintained and updated by the government. These are a great starting point, as they provide exactly the kind of information you need for your letter campaign.

Companies like Moneyhouse and Bisnode are paid services which provide a similar, but more bespoke service.

Another approach involves using Builtwith. This is a massive technology directory which allows you to find highly targeted websites. As an example, Builtwith could show you every UK-based domain, which uses WooCommerce, and provide you with an appropriate email address.

Once you have a list of websites that fit your audience, head over to Fiverr, Upwork or PeoplePerHour. Here you will find freelancers to visit the domains, navigate to the about section, and write down the postal address. Once the postal addresses have been added, you’re ready to send off your campaign.

Finding the right mail provider

Which mail provider is best suited to you, will depend on your requirements. For domestic letter campaigns, your national post service will most likely be the cheapest option. In Germany, the Deutsche Post services enterprise customers from Mailingfactory.

The average price for single-page, coloured letter is about €0.72. This includes the possibility of personalisation which is vital to the success of your campaign. Always address your recipients by name, and never with a generic catch-all phrase.

In the UK, there are a number of services which offer high volume letter campaigns. DirectMailings for example offers attractive prices, with just £0.57 each for 3,000 letters.

For international direct mail campaigns my favourite solution is Lob. This service isn’t quite as straightforward in terms of user experience, but ultimately offers decent prices and great personalization.

Nailing your messaging

You’ve got to be aware of the fact that the vast majority of recipients will not even open your letter. Thus it’s absolutely crucial that the small percentage of people who do see it are wowed by it.

To increase the chances of that happening, try to consider the following things:

  • Always address the recipient by their name (ideally formal)
  • Include bullet points which summarize your value proposition
  • Choose a large font-size (16px or higher)
  • Ensure the letter is understandable at a glance (bold important sentences, numbers, include sub-headings)
  • Include trust symbols, like review aggregators and awards
  • Include a discount and create urgency by making it time sensitive
  • End it with a signature

Keeping these points in mind will significantly increase your chances of launching a successful letter campaign.

Conclusion - What I’ve learnt sending 10,000+ letters

Letter campaigns are the hardest acquisition channel to get right. The lack of an effective feedback loop, and lacklustre data make it incredibly difficult to optimize.

But if done right, direct mail can be the life-blood of your business. Letters hold a gravitas that emails and other forms of advertising simply don’t. The astronomical response rates confirm this.

To make direct mail a success, you need to embrace one word: “testing”. Spend some time designing 3-4 different versions of the same letter and send them out in small batches. Each should contain a unique coupon code. 2 weeks after the expected delivery, head over to Google Analytics and identify the letter with the highest engagement rate.

Then create 3-4 versions of the successful letter and send out some new campaigns. Only this way, can you tentatively optimize and build a scalable direct marketing strategy with a positive ROI.

Thanks for reading and see you next week.