With the use of a construction calculator, you can get a fairly accurate estimate, but it depends on the quality of the data you put into the machine. Costs can vary due to local inflation, material expenses, the difficulty of the project and market conditions. Many professionals will use a construction calculator as a starting point, and then make adjustments to the estimate according to the conditions at hand. It doesn't forecast each and every expenditure, however it gives valuable data for spending and planning. Estimates using a calculator along with expert advice can usually give a more precise prediction of project costs.