This is the {{convert}} subtemplate for the Irish acre of 7840 square yards. As with the English acre, the Irish acre is 160 square rods.

1 acre  = 1 furlong × 1 chain
= 10 square chains              ∵  1 furlong  = 10 chains
= 10 × (4 rods)2 1 chain  = 4 rods
The Irish rod, however, is 7 yards as opposed to the 5 12-yard English rod.
∴ 1 Irish acre = 10 × (4 × 7 yards)2
= 10 × (4 × 7 × 0.9144 metres)2
= 6555.2385024 square metres