Royal Mail First Class vs Second Class: Which Should You Use?

Choosing between Royal Mail First Class and Second Class sounds simple, but the right answer depends on what you are sending, how urgently it needs to arrive, and whether you need proof of delivery. Here is a plain-English breakdown of both services.

The basic difference

Royal Mail aims to deliver First Class letters by the next working day after posting. Second Class letters are targeted for delivery within 2 to 3 working days. Both figures exclude Sundays and bank holidays.

These are targets, not guarantees. Royal Mail publishes performance statistics showing that First Class consistently delivers around 93 to 95% of letters on time. Second Class performs similarly at the 2 to 3 day window. Delays are more common in December and around bank holidays.

Cost comparison (2026)

As of 2026, Royal Mail stamp prices for standard letters (up to 100g, DL or C5 envelope) are:

Prices shown are retail stamp prices. Online letter posting services include printing, envelope and postage in a single fee.

When to choose Second Class

Second Class is the right choice when:

• The letter is not time-sensitive (personal correspondence, information letters, non-urgent notices)
• You are sending in bulk and cost per letter matters
• You are sending a card or personal letter to someone within a few miles
• You do not need proof that the letter was received

For most everyday letters, Second Class is entirely adequate. The one-to-two day difference in delivery time rarely makes a practical difference unless there is a deadline involved.

When to choose First Class

First Class makes sense when:

• You are sending close to a deadline (for example, a tax return, a job application, or a response to a legal notice)
• The extra 50p per letter is not a concern relative to the importance of the correspondence
• You want to make a good impression with a professional or business letter

When neither is enough: Tracked services

Neither First Class nor Second Class includes tracking or delivery confirmation. If you are sending anything where you need proof of posting or proof of delivery, standard First or Second Class is not sufficient. You should use:

• Royal Mail Tracked 24 or Tracked 48 for a tracking number and online delivery updates
• Special Delivery Guaranteed for a money-back guarantee on delivery time, signature on delivery and compensation up to £750 (or £2,500 with enhanced compensation)

Legal correspondence, court documents, formal complaints, important financial letters and anything addressed to HMRC, the DVLA or similar bodies should generally use a Tracked or Special Delivery service.

The verdict

For casual, non-urgent correspondence, Second Class is perfectly reliable and saves money. For anything with a deadline or moderate importance, First Class is a sensible upgrade. For anything legally significant or requiring proof of delivery, bypass both and use a Tracked service.