UK parcel size checker
Enter package dimensions (length, width, height in cm or mm) and weight (g or kg) to instantly classify your parcel into UK postal bands: Letter, Large Letter, Small Parcel, or Medium Parcel. Identifies oversize packages and alerts you when minor packaging adjustments could qualify your item for a cheaper postal category. Client-side only; estimates based on published Royal Mail consumer guidelines.
Client-side band helper · Royal Mail 2024–2026 limits · No live postage prices
Longest side
Second dimension
Thickness / depth
Scale weight
Large Letter
Allowed up to 750 g for this format.
30 × 21 × 2 cm
2 cm
450 g
750 g
- Fits within all Large Letter physical dimensions and weight limits.
UK Postal Bands Reference (Royal Mail)
Evaluated using cm & g| Band | Max Dimensions (L × W × H) | Max Weight | Typical Items | Fits Your Parcel |
|---|---|---|---|---|
Letter | 24 × 16.5 × 0.5 cm | 100 g | Personal letters, Greeting cards, Invoices | Exceeds |
Large LetterSelected | 35.3 × 25 × 2.5 cm | 750 g | A4 documents, Magazines, Slim books | Fits |
Small Parcel | 45 × 35 × 16 cm | 2000 g | Shoes in box, Folded hoodies, Cosmetics hampers | Fits |
Medium Parcel | 61 × 46 × 46 cm | 20000 g | Winter coats, Kitchen appliances, Bulky toys | Fits |
Oversize / Courier | > 61 × 46 × 46 cm | > 20,000 g | Parcelforce, DPD, Evri Large, Pallets | N/A |
Royal Mail 2024–2026 Consumer Format Specifications & Disclaimer
Size and weight limits are derived from published Royal Mail consumer format standards (royalmail.com/sending/uk/size-weight-limits).
This tool is a physical size and weight band helper, not live postage pricing. Royal Mail and courier postage prices vary by service (1st Class, 2nd Class, Tracked 24/48, Special Delivery) and change over time. Always verify parcel dimensions and check current rates with Royal Mail or your shipping platform before buying postage.
Related Shipping Calculators
Example
A4 padded book mailer
A padded envelope measuring 30 × 21 × 2 cm weighing 450 g fits within the 35.3 × 25 × 2.5 cm and 750 g limits for Royal Mail Large Letter. If thickness expands to 2.8 cm, it steps up to Small Parcel.
Related: Etsy fee calculator, Dimensional weight calculator
FAQ
- What is the difference between a Large Letter and a Small Parcel?
- A Royal Mail Large Letter allows dimensions up to 35.3 × 25 × 2.5 cm and a maximum weight of 750 g, designed to slide through standard UK home letterbox slots (25 mm). A Small Parcel permits up to 45 × 35 × 16 cm and a maximum weight of 2 kg. Large Letter rates are significantly cheaper than Small Parcel, making packaging thickness under 25 mm a key target for e-commerce sellers.
- How should I measure my parcel dimensions?
- Measure the maximum outer length (longest dimension), width (second longest), and thickness or depth (shortest dimension) including all packaging, bubble wrap, tape, and bulging contents. UK postal sorting offices measure the three-dimensional outer bounding box, so any bulge exceeding a limit will cause the parcel to be reclassified.
- What happens if my package is slightly over the size or weight limits?
- Royal Mail and UK sorting hubs use physical measuring gauges (aperture templates) and automated 3D optical volumetric scanners. If an item exceeds a slot by even 1–2 mm or exceeds the weight band, it is flagged as underpaid. The recipient will receive a grey fee-to-pay notification card with a surcharge (the postage difference plus an administrative handling fee), or the item will be returned to the sender.
- Does this checker show live Royal Mail postage prices?
- No. This tool is a size and weight band classification helper, not a live postage pricing calculator. Postal tariffs change periodically across services (1st Class, 2nd Class, Tracked 24, Tracked 48, and Special Delivery Guaranteed). Once you know your parcel band, check Royal Mail's website or your parcel shipping platform (such as Click & Drop) for current rates.
- What is the difference between UK parcel size bands and dimensional (volumetric) weight?
- Royal Mail consumer domestic services classify mail into fixed physical size bands with fixed maximum dimensions and weight caps. In contrast, international couriers (such as FedEx, DHL, and UPS) and air freight calculate dimensional weight (Length × Width × Height / divisor) and charge based on whichever is greater between physical scale weight and volumetric weight.
- Can I send tubes or rolled posters as Small or Medium Parcels?
- Yes. Royal Mail accepts roll and cylinder formats: for Small Parcel, the maximum length is 45 cm and the length plus twice the diameter (L + 2D) must not exceed 104 cm (max 2 kg). For Medium Parcel, the maximum tube length is 90 cm and length plus twice the diameter must not exceed 104 cm (max 20 kg).