SI is the accepted abbreviation for the metric system and stands for the international system. Suggested orders of accuracy are as follows:


Building Plans are measured to the nearest millimetre.
Building area to nearest .1 of a square metre


$/m2 per annum for commercial and $/m2 per week for residential


Recommended scale ratios are 1:50, 1:100, 1:200, and decimal multiples of these. 1:20000 is a useful scale for typical rural properties.


1m 100cm 1000mm
1km 1000 m
1cm 10mm
1 foot 0.305 m
1 mile .61km.

Mortar gap between bricks: 9.525 mm

1m 3.28'
10' 3.048m
15' 4.572m
20' 6.096m
25' 7.62m
30' 9.144m
33' 10.06m
40' 12.19m
45' 13.72m
50' 15.24m
55' 16.76m
60' 18.29m
65' 19.81m
66' 20.12m
70' 21.34m
80' 24.38m
90' 27.43m
99' 30.18m
100' 30.48m
1chain 20.12m
1m 3.28'
1link 20.12cm
1km 1000m
1mile 1.609km


1ha 10000m2 2.471 acres
1km2 100ha 100000 m2
1ft2 0.0929 m2
1perch 25.3 m2
1rood 1012 m2
1acre 4047 m2
1mile2 2.59 km2
1m2 10.764 ft2
2acres 0.8094ha
5 acres 20235m2 2.0235ha
1square (100ft2) 9.29m2


1m3 1kl 1000l
1l 1000ml
1ft3 0.0283m2
1gal 4.55l


1kg 1000g
1t (tonne) 1000kg
1lb 453.6g
1ton 1.02t

Note it is illegal and unprofessional to advertise in imperial units. If an agent must use the old measurements then he/she should at least show both metric and imperial measurements.