If you’ve typed “do letters still work in marketing?” or “how effective are letters as a marketing tool in 2026” into Google, you’re probably staring at a marketing budget, wondering whether physical mail is a relic — or the one channel your competitors aren’t using properly.
Here’s the short answer: yes, letters still work — arguably better than they ever have. The 2025 ANA Impact Pulse puts the average direct mail response rate at 4.4%, against email’s 0.12%. That’s not a typo. Direct mail is converting at roughly 37x the rate of email, and open rates sit between 78–90%, compared to the 20% you’ll get from an inbox that’s actively trying to ignore you.
But — and this is the part most “direct mail is back” articles skip — a high response rate on paper doesn’t automatically mean a good return for your business. The real question for a B2B company in the UK isn’t “do letters work?” It’s “do letters work for the money and effort I’m about to put in?” That depends entirely on three things most companies get wrong: who you send to, what you send, and what happens after it lands.
So, How Effective Are Letters as a Marketing Tool in 2026?
More effective than most marketers assume, and considerably more effective than the inbox-fatigued, spam-filtered, AI-generated-newsletter version of email that B2B buyers scroll past without reading.
The numbers that matter:
- 4.4% average response rate for direct mail vs 0.12% for email (ANA/DMA 2025)
- House lists (existing customers) see 5–9% response; cold prospect lists see 2–5%
- 161% ROI for direct mail to house lists — the highest ROI of any paid channel, per ANA
- 84% of consumers read mail the same day it arrives
- 95% of marketing teams are increasing direct mail investment in 2026 (Lob Business Insights)
In a B2B context specifically, this matters even more — a decision-maker’s inbox is defended by spam filters, EAs, and inbox triage habits. A letter on their desk bypasses almost all of that. It’s rare enough now to be noticed, which is exactly why it works.
So no, letters aren’t a nostalgia play. They’re a genuinely under-used channel precisely because everyone assumed digital killed them.
Response rate: direct mail vs. email
Direct mail converts at roughly 37x the rate of email · Source: ANA/DMA 2025
The Real Cost of Sending Letters (And Why DIY Often Doesn’t Pop)
This is where most companies either overspend or underspend into irrelevance. Let’s break down what a letter actually costs in the UK right now:
Postage
Royal Mail 1st Class is now £1.80 per stamp (April 2026 price rise). 2nd Class and bulk/Mailsort rates bring that down significantly — but only at volume, and only if you know how to access the discount tiers.
Envelopes
5–10p each, more for anything branded or windowed.
Print & paper
10–15p per sheet for basic colour print; more for anything that doesn't look like a council tax reminder.
Creative
This is the one people skip, and it's the one that decides whether your letter gets read or binned. A well-designed, well-written piece from a specialist creative costs real money — but a cheap one looks like junk mail, and junk mail gets junk-mail treatment: bin, no second thought.
Do the maths on 1,000 letters sent DIY — stamps alone at £1.80 is £1,800, before envelopes, print, design time, or the hours spent stuffing and queuing at the Post Office. Via bulk mailing discounts that figure can drop to roughly £690–£900 all-in for the same volume. The gap between “sent letters” and “sent letters that actually convert” isn’t the postage — it’s whether the creative behind it was built to be read by a B2B buyer, or thrown together in Canva the night before.
The uncomfortable truth: you can do it yourself. Most companies do. Most of those campaigns underperform, not because letters don’t work, but because a generic, self-designed mailer sent to the wrong 1,000 businesses was never going to pop in the first place.
Letters vs. Email: The Real Engagement Numbers
Here’s the direct comparison, so you’re not choosing blind:
Response rate
Direct Mail: 4.4% average (5–9% house list)
Email: 0.12% average
Open rate
Direct Mail: 78–90%
Email: ~20%
Click / engagement
Direct Mail: Physical action: call, scan, visit
Email: 2.3% unique click rate
Cost per piece
Direct Mail: ~£0.69–£1.80+
Email: ~£0.01–£0.02
Perceived trust
Direct Mail: High — tangible, considered
Email: Low — disposable, filtered
Email wins on cost-per-send by a mile. Letters win on cost-per-response by an even bigger one, because a 0.12% click rate on a free channel still means you’re paying (in time, tooling, and opportunity cost) for 999 ignored emails to get one engaged lead. Letters flip that ratio.
The honest framing: email and letters aren’t competitors, they’re a sequence. The data backs this up — 75% of marketers now run multichannel, and direct mail recipients who also see a digital touchpoint are 31% more likely to engage. The letter opens the door. What happens next decides whether anyone walks through it.
The Problem Nobody Talks About: What Happens After You Post the Letter
This is where most B2B direct mail campaigns quietly die, and it’s rarely the letter’s fault.
- Who do I even send it to? Most companies either buy a generic, bloated prospect list or guess based on postcode and SIC code — spray and pray, dressed up as “targeting.”
- How do I know if it worked? A letter with no tracking mechanism is a black box. You post 2,000 letters and… hope?
- What do I do when someone responds — or doesn’t? A single warm reply with no follow-up system is a wasted £1,800 spend. And a non-response isn’t a “no” — it’s just touchpoint one of many.
Direct mail’s own research backs this: 45% of consumers need two to three mailings before they act, and B2B decision-making cycles are longer still. A single, unfollowed letter is a lottery ticket. A system is a pipeline.
How Mailsource Fixes This
This is the gap Mailsource was built to close — not “send letters,” but make letters actually convert for B2B pipelines:
Precision targeting, not spray and pray
We use a data model to identify your exact customer profile — not a generic SIC-code list, but the businesses that actually match your best customers — so every letter lands on a desk that's worth landing on.
Creative that's built to be read
We work with creatives who specialise specifically in this medium, because a letter designed like a flyer gets binned like one. Direct mail has its own visual language, and it's not the same as a landing page.
Unique QR code tracking on every letter
No more black box. You see exactly who scanned, when, and what they did next — turning a physical mailer into a measurable, trackable channel like any digital one.
The 11–14 touchpoint follow-up system
Drawing on learnings from one of Mailsource's founders, who spent time selling for Revolut and other tech SaaS businesses — most B2B sales happen somewhere between the 11th and 14th touchpoint, not the first. Mailsource doesn't treat the letter as the campaign — it treats it as touchpoint one. Letters open the conversation, but Mailsource's true value add is the effort put into following up on each targeted letter — turning a warm introduction into a sale.
The Bottom Line
Letters still work in 2026 — the response rate data makes that case on its own. But “letters work” and “my letter campaign will work” are two different claims. The companies getting 5–9% response and genuine ROI aren’t the ones who print the nicest card stock. They’re the ones who know exactly who to send to, make sure the letter is designed to be opened, can actually track what happens next, and have a follow-up system that turns one touchpoint into the dozen it usually takes to close a B2B deal.
If you’re asking “do letters still work in marketing?” — the answer is yes, if you treat the letter as the start of a relationship, not the whole pitch.