An A4 sales letter is a printed, addressed letter that makes a single offer to a named reader and asks for one action. It works when the reader already has a reason to care and the offer needs more explanation than a postcard can hold.
Overview
A sales letter reads as correspondence rather than an advert. It has a salutation, a headline or opening line that names the reader’s problem, a few paragraphs that explain the offer and its proof, a clear call to action and a signature. The A4 page gives you room to answer the obvious objections before the reader has to ask.
The classic structure still works: attention, interest, desire, action. Open with the reader’s situation, not your company history. Explain what changes for them, show why they can believe it, and end with one specific next step and a deadline if there is a genuine one. A postscript is often the most-read line after the opening, so use it to restate the offer.
Keep the design quiet. A letterhead, generous margins and a readable font make the letter feel personal. Heavy colour and stock photography make it look like a flyer, which undoes the main advantage of the format.
When to use it
How to start, step by step
- Define the reader and the offer. Write one sentence that says who the letter is for and what you are asking them to do. If it takes two offers to fill the page, split them into two mailings.
- Draft the opening line first. Lead with the reader’s problem or goal. The first sentence decides whether the rest gets read.
- Add proof you can stand behind. Use facts you can verify: what the service includes, your guarantee, how long you have operated. Do not invent figures or testimonials.
- Make the action easy. Give one route to respond, such as a short web address, a QR code or a direct phone number, and a reference code so you can count replies.
- Approve the print file. Check names, merge fields and the address window position on the exact print file before you approve it.
Which format to choose
| Use | Format | Why | From, per item |
|---|---|---|---|
| Single offer, one page of copy | Letter — A4 | Reads as a personal letter and fits a full argument on one side. | £1.90 |
| Short teaser that leads to a website | Postcard — A5 enveloped | Arrives in an envelope but carries a briefer, more visual message. | £2.20 |
| Letter plus product images | A3 to A5 Enveloped | Folded pages give room for pictures alongside the copy. | £2.45 |
Prices come from the live AutoLetters price list. They include printing and UK postage, are the same at any quantity, and have no VAT added because AutoLetters is not VAT registered.
Worked example
Illustrative scenario, not a customer case study. A local accountancy practice writes to 500 named small-business owners offering a fixed-fee year-end review. The letter is single-sided, signed by a partner, and carries a reference code for the booking page.
500 × Letter — A4 at £1.90 each = £950.00, printed and posted.
Response depends on your list, offer and timing, so we do not quote response rates. Measure your own with a unique code or web address.
Mistakes to avoid
- Opening with your company story instead of the reader’s problem.
- Two or three offers in one letter, so none of them gets acted on.
- Designing it like a flyer and losing the personal feel.
- No reference code, so you cannot tell which replies came from the letter.
Preparing artwork that prints correctly
Every format has a trim size, a bleed area and a safe zone. Extend background colours and images into the bleed so no white edge appears after cutting, and keep text, logos and QR codes inside the safe zone. Use images at 300 DPI at printed size, and leave the address area clear, because the printer adds the recipient's address there. Each product page lists the exact supplier measurements, and Lenny checks uploaded artwork against them before you approve it.
Building a list you can use
You can send to a list you already hold or to an audience of UK addresses built around a postcode. If you use your own list, include only people you have a lawful basis to contact by post, remove anyone who has asked not to hear from you, and keep a record of where the data came from. The Information Commissioner's Office publishes guidance on direct marketing under UK GDPR. Check that every address is complete and current: incomplete addresses cost money and do not arrive.
Measuring the result
Decide how you will count responses before you send. A unique discount code, a short web address, a dedicated phone number or a simple “how did you hear about us?” question all work. Divide the campaign cost by the number of responses to get a cost per response, then compare it with your other marketing. Where you can, hold back a small group from the mailing, so you can see how many of them would have responded anyway.
How AutoLetters handles it
Lenny, the AutoLetters AI campaign specialist, helps you choose a format, drafts the wording and artwork to the printer's exact measurements, and helps build the audience: either UK addresses around a postcode or a list you already hold. You review a print-accurate preview, then approve the exact print file. Nothing is printed or posted until you approve it.
AutoLetters sends addressed mail to UK addresses only and does not offer unaddressed door drops. Postal delivery timings are not guaranteed.
Questions
How long should a sales letter be?
As long as it needs to answer the reader’s questions and no longer. Many work on one side of A4; use both sides only when the extra space carries useful detail.
Can each letter be personalised?
Yes. Names and other fields from your list can be merged into each letter, and you check them on the print file before approving.
Plan your campaign with Lenny
Describe what you want to promote and who should receive it. Planning is free and needs no account.
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