Calculating roughly is often used to describe an approximate estimation, which means we are trying to guess or estimate a quantity without exact numbers or measurements. Some antonyms of calculating roughly could be, exact calculation, precision, accuracy, meticulousness, or carefulness. If we want to avoid estimating and make sure we have an exact calculation, we need to use precise measurements, tools or techniques, like a ruler, a scale, or a calculator. Similarly, meticulousness and carefulness in our work could ensure the accuracy of the calculations or estimations. Therefore, it is always better to use antonyms of calculating roughly for better results in data analysis, engineering, or scientific research.