We have tried to be accurate with the above table but cannot be held responsible for in-accuracies.
Go back to first principals and double check your calculations if the result is 'mission critical'.
Even the brilliant brains at NASA have made a conversion error or two !

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

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 prefixes can be found on another 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.