Hectares to Mẫu (Northern Vietnam): the quick answer
1 ha = 2.77778 mẫu-b
1 hectare equals 2.77778 mẫu (northern Vietnam)
To convert hectares to mẫu (northern Vietnam), multiply the value by 2.77778. To go the other way, multiply mẫu (northern Vietnam) by 0.36 to get hectares.