Imperial to metric conversions

(approximate)

To change:                Into:                              Multiply by:

1 inch                      millimetres                     25.4
1 inch                      centimetres                    2.54
1 foot                      millimetres                     305
1 foot                      centimetres                    30.5 
1 foot                      metres                           0.305  
1 yard                     millimetres                     914
1 yard                     centimetres                    91.4
1 yard                     metres                           0.914
1 chain                    metres                          20
1 furlong                  metres                          200
1 mile                      metres                          1609
1 mile                      kilometres                    1.61
1 nautical mile          kilometres                    1.85
 

5 links = 1 .0058 metres

1 chain = 20.1168 metres

1 perch = 25.293 square metres

1 rood = 1011.68 square metres

Quick conversions

Inches to millimetres - multiply by 25; or add two zeros and divide by 4.

Yards to metres - deduct 10 per cent.

Miles to kilometres - multiply by 8, divide by 5.

Note:

Horses are measured in hands (units of about 10 centimetres). A pony is a horse measuring under 14 hands in height.

The altitude of an aircraft is measured in feet: a Boeing 737 generally cruises at 25-35,000 feet, except for short journeys, when it would cruise at 9-11,000 feet.

Area

square millimetre (mm2)

square centimetre (cm2) = 100 mm2

square decimetre (dm2) = 100 cm2

square metre. (m2) = 1,000,000 mm2 or 100 dm2

are (a) = l00m2

decare (daa) = 10 a

hectare (ha) = 10,000 m2 or 10 daa

square kilometre (km2) = 1,000,000 m2 or 100 ha

(approximate)

To change:                   Into:                              Multiply By :

1 square inch               square millimetres           645

1 square inch              Square centimetres         6.45

1 square foot                square metres               0.092

1square yard                square metres                0.836

1 rood                          ares                             10.1

1 acre                          hectares                          0.405

I square mile                 hectares                          259

I square mile                  square kilometres            2.59

Quick conversions:

Square inches to square centimetres multiply by 6.5

Square yards to square metres: multiply by 5, divide by 6.

Perches to square metres multiply by 25

Acres to hectares: multiply by 2, divide by 5.

Square miles to square kilometres: multiply by 5, divide by 2.

milligram (mg)

gram (g} = 1000 mg

kilogram (kg) = 1000 g

megagram (Mg) = 1000 kg

tonne (t) = 1 Mg or 1,000 kg

To Change                      Into                      Muiltiply by

1 dram                            grams                     1.77

l ounce                            grams                     28.3

1 pound                           kilograms                0.45

1 stone                           kilograms                 6.35

1 hundredweight               kilograms               50.8

1 ton                               kilograms                 1016

1 ton                                tonnes                      1.01

Quick Conversions

Ounces to grams: multiply by 30.

Pounds to kilograms: deduct 10 percent and divide by 2.

Hundredweights to kilograms: multiply by 50.

Volume

Cubic millimetre (mm3)

Cubic centimetre (cm3) = 1000 mm3

Cubic decimetre (dm3) = 1000 cm3

Cubic metre (m3) = 1000 dm3

Tochange:                   Into:                             Multiply by:

I cubic inch                 cubic centimetres          16.4

1 cubic foot                cubic metres                  0.028

1 cubic yard.                 Cubic metres               0. 765

220 gallons                    cubic metres                1

Quick conversion

Cubic yards to cubic metres: multiply by 3, divide by 4

Capacity (liquid volume)

A teaspoon holds about 5 millilitres.

A dessertspoon holds about 10 millilitres.

A tablespoon holds about 15 millilitres.

Quick conversions Pints to litres: multiply by 0.6:

Gallons to litres: multiply by 4.5.

To change                       Into:                      Multiply by

1 fluid ounce                    millilitres                28.4

1 pint                              millilitres                    568

1 pint                                  litres                     0.57

1 quart                              litres                       1.14

1 gallon                             litres                       4.55

1 bushel                             litres                     36.3

1 US pint                            millilitres                473

1 US quart                          millilitres               946

1 US gallon                        litres                     3.78