Yes, I can and do estimate accurately, as can many others. Estimation is a basic engineering skill. McConnell's book, linked to by the other contributor, is a

Yes, I can and do estimate accurately, as can many others. Estimation is a basic engineering skill. McConnell's book, linked to by the other contributor, is a sensible introduction to doing reasonably accurate estimates for projects that aren't incredibly huge (10MLOC+). Very accurate estimates (within 5-10%) and estimates of incredibly huge projects are also possible but require specialist estimators with extensive training and practice.