We have tried to be accurate with the above table but cannot be held responsible for inaccuracies.
Go back to first principals and double check your calculations if the result is 'mission critical'.

The scientific notation used in the factors column helps to reduce long numbers to a manageable width. E+01 means moving the decimal point one space to the right so 1.00E+01 is shorthand for 10, then 1.33E+00 stays at 1.33 and 1.33E-01 becomes 0.133. The format tends to be used when the figure gets longer so E+09 or E-09 cuts out a lot of noughts.

Example:-
Task: How many sq.rods in 10 acres.
From the tables: 1 acre = 160 sq.rods, so
10 acres x 160 = 1600 sq.rods
When you want to reverse the conversion,
divide by the factor viz.
1600 sq.rods/160 = 10 acres

Impossible Conversions
Remember that you cannot create energy only convert it. Likewise, you will not find a conversion from pounds to metres - the basic units must remain the same - mass converted to mass, length converted to length, et al.

You won't usually find a conversion from kilograms to grams - the prefix 'kilo' means '1,000' so a kilogram is in fact 1,000 grams in the same way as a kilometer is 1,000 metres [or about 1,000 yards in 'old money']. I have put a few in the table because visitors have asked for them. More examples can be found on the prefix table.

One handy metric link between units to remember is that 1 Litre [1000cc] of pure water weighs 1 kilogram.

If accuracy is critical beware of old versions of MS Excel which had problems rounding off numbers.

Metrication is a great help but has also created anomalies; I have seen pressure gauges changed from a commonly used psi to kg/cm.sq., bar, pascal, kPa and atmos but will no doubt move to a popular metric standard in a few decades.

More information on the SI System (Le Système International d'Unités) base units and definitions.