PROBLEM TO BE SOLVED : 1 as a basis for determining how much of the area or accurate, real estate prices large difference is generated, the transaction for the situation is not concerned can be overlooked. Therefore, an accurate or precise area calculator for calculating a real estate area. SOLUTION : with the housing, the input part and the surface of the casing and is provided with a display part in the calculator, the basis of the input part 1 as an input means for an accurate centare value is provided. 1 as a basis of accurate centare value 3. 305124 is adopted. 1 on the basis of the above accurate centare value (basis conversion factor) is inputted from the input means is calculated from the value of real estate centare area, or area and from centare value. Selected drawing : fig. 1