Do you want to know which envelope is best to use to ensure cheap postage? You're not alone - this is a question we get asked a lot! You may be like many of our savvy customers who want to keep postage costs a low as possible. Something as simple as choosing a slightly smaller envelope can take you from a parcel rate to letter rate, saving significantly per item sent! Obvious, yes – but not always the first thing people consider when planning a mailing. Quite often the envelope contents are designed, printed and produced ahead of the envelope decision and this can cost a business thousands in unnecessary expense. Whether it's a direct mail campaign, large scale mailing or general business post, by saving a even a few pence per item sent can make a huge difference over a year. The cheapest way to send mail in the UK is by Royal Mail 2nd Class Letter Post. A 2nd class standard letter stamp costs 56p. To use this mail format, your envelope must be within the following limits when filled and sealed ready to post:

Standard Letter Post

• Envelope Maximum Dimensions = 240mm x 165mm (24cm x 16.5cm)
• Envelope Maximum Thickness = 5mm (0.5cm)
• Envelope Maximum Weight = 100g

The following standard envelope sizes are all suitable for standard letter post:

• C7 Envelopes @ 82mm x 113mm
• C6 Envelopes @ 114mm x 162mm
• DL Envelopes @ 110mm x 220mm (or 114mm x 229mm for oversized DL)
• C5 Envelopes @ 162mm x 229mm

C5 size envelopes are the largest standard envelope size that can be used for Royal Mail standard letter post. If you want to get the most for your money, this is a great envelope choice. Indecently, if you are looking at postage costs ahead of a direct mail campaign, you might be interested to know that coloured envelopes are 9 times more likely to be opened than white envelopes! A great tip to improve open rates (especially great as if you use a C5 envelope you can save on your postage costs too – win win!). Don’t forget you will need to ensure that the total weight is less than 100g and the thickness of the envelope less than 5mm. For more information and guidance on which envelopes to choose for the various Royal Mail postage rates, please see our handy guide page Postage Rates for Envelopes. Information correct as of 23^rd January 2018. Please use this page as a guideline. We always recommend measuring/weighing your postage and checking the Royal Mail website for the most up to date rates & cannot be held responsible for any costs incurred due to the above information.

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