Size and weight requirements

Each Registered Mail™ item must meet the size and weight specifications shown below.

Please note:

  • The metric unit is the official measure. We only provide Imperial equivalents for reference and convenience.
  • The longest dimension is the length, the second longest dimension is the width.

Standard Registered Mail 

Metric
Imperial
Requirement Minimum Maximum
Length
140 mm
5.6 inches
245 mm
9.6 inches
Width
90 mm
3.6 inches 
156 mm
6.1 inches
Thickness
0.18 mm
0.007 inches
5 mm
0.2 inches
Aspect ratio 1
1.3 to 1
1.3 to 1
2.6 to 1
2.6 to 1
Weight
2 g
0.07 ounces
50 g
1.76 ounces

1 The aspect ratio is the relationship between the length and the width. Standard Lettermail must be rectangular. Items that don’t meet this ratio (for example, square items) are subject to Other Lettermail prices.

Other Registered Mail

Metric
Imperial
Requirement Minimum Maximum
Length
140 mm
5.6 inches
380 mm
14.9 inches
Width
90 mm
3.6 inches
270 mm
10.6 inches
Thickness
0.18 mm
0.007 inches
20 mm
0.8 inches
Weight
5 g
0.17 ounces
500 g
17.6 ounces

Prepaid Registered Mail envelopes

Metric
Imperial
Requirement Standard letter Other letter
Length
240 mm
9.4 inches
318 mm
12.5 inches
Width
150 mm
5.9 inches
241mm
9.5 inches
Weight
50 g
1.76 ounces
200 g
7.1 ounces