Avoiding Royal Mail surcharges: a practical guide

Royal Mail surcharges are added when mail does not meet the guidelines – usually from the wrong size or format, underpaid postage, poorly affixed labels, or an unreadable frank. You can avoid nearly all of them by measuring and weighing every item before franking and keeping your machine well maintained.

What are Royal Mail surcharges?

Surcharges are additional fees added when mail items do not meet Royal Mail’s guidelines. They typically arise from incorrect sizing, insufficient postage, or packaging issues. Common reasons include:

• Incorrect size or weight.
• Poorly affixed labels.
• Non-machineable items sent as standard.
• Incorrect format (for example Large Letter vs Small Parcel).
• Unreadable barcodes or franks.

Top reasons for surcharges (and how to avoid them)

1. Incorrect sizing or format

One of the most common mistakes is sending an item as a Large Letter when it qualifies as a Small Parcel, which triggers an automatic surcharge. Solution: use a Royal Mail size guide before franking – even 30 seconds spent checking avoids the risk. If you are a Mailcoms customer, we include size guides with every online order. Order your franking supplies here.

2. Overfilled or bulky envelopes

Stuffing envelopes too full can push them into a different size category even when the weight is low. Solution: use your franking machine’s integrated weighing scale to weigh every item, and choose the right envelope for the contents without overstuffing. View our range of business envelopes here.

3. Unreadable or misaligned franks

If the frank or Mailmark impression is smudged, faint or in the wrong position, it may not scan, leading to a surcharge. Solution: keep your machine well maintained, clean the printhead regularly, and use approved franking ink and quality labels.

4. Incorrect weight or postage selection

Guessing postage or selecting the wrong weight band often leads to underpayment – just as costly as overpaying. Solution: weigh on your franking machine’s scale before franking, and double-check you have selected the right class and format.

Tools to help you stay compliant

• Mailcoms size guides – keep one near your franking machine. See how to use it correctly here.
• Your franking machine’s integrated weighing scales – essential for weighing mail correctly every time.
• Approved labels and ink – for clear, scan-ready franks.
• Royal Mail guidelines – check their official site for current franking and sending standards.

Conclusion

Avoiding surcharges does not require a major investment – just better awareness and preparation. With the right tools and habits, your business can reduce waste, save money and ensure smoother deliveries. If you are interested in getting a franking machine or upgrading to Mailmark with lower prices available, please view our franking machine page here or call us today on 01543 572 776. Mailcoms is a Royal Mail Authorised Independent Inspector & Maintainer of postal franking machines, serving over 40,000 customers across the UK.

Frequently asked questions

What causes a Royal Mail surcharge?

Incorrect size or weight, insufficient postage, poorly affixed labels, non-machineable items, or unreadable barcodes and franks.

How do I avoid a surcharge?

Measure with a size guide, weigh every item on your franking machine’s scale, select the correct class and format, and keep the printhead clean for a readable frank.

Can a franking machine help avoid surcharges?

Yes – its integrated scale applies the correct postage every time, removing the guesswork that leads to under- or over-payment.