(1500000000+1.00067968)-(1500000000+1.00067961) Out[102]: 2.384185791015625e-07 1.00067968-(1.00067961) Out[103]: 7.000000001866624e-08 above i am showing the two different results,though the two outputs should be same if we do it in copy(the lass one is acceptable value). so my question is how to increase the accuracy(windows7(32bit) ,python2.7.2)