Rise of consumer prices as measured by CPI?  Net increase in money supply?  Gross increase in money supply?  Excess increase in money supply over some criteria?  (And what does "Excess" mean?)

Each of these have their uses for reasons too long to get into here.  

The usual figure used to estimate inflation in quantification analysis is the Consumer Price Index more to keep things somewhat simple than the superiority of the (political massaged) figure.  As I shall attempt to show.  

To really get at inflation you need to take the total rise of M3 minus the amount of increase used for long and medium term investment (> 1 year) as adjusted by the rise (if any) in the cost of goods and services caused by that increase in M3, the overall price affect by the increase, minus the amount of loss actually realized during the time period in any investment, the velocity of the money (how fast the currency changes hands)  ... and I'm sure I've forgotten something(s).  This indicates why M3 is so important as it is the basis from which any further calculation must start.

I like to use the M3 figure as a stand-in for how much the plutocrats have had to play with, as they are first in line to get the additional money, and the yield on the 10 year bond for the market consensus prediction of inflation over the time to maturity (1 month, 3 years, 7.5 years ... whatever.)  

The difference between these two figures should, roughly, agree with GDP if the money supply is 'stable.'  Over the last 4 years they have not agreed intimating Greenspan has been pumping more money into the economy than is actually required causing the excess to flow into the housing and other bubbles.

MHO.  YMMV.