Only the rough guess and estimate can be made of it.

对此只能作出一个粗略的测算。

《新英汉大辞典》

We were only able to make a rough estimate of how much fuel would be required.

我们只能对所需燃料的量作一个粗略估计。

《柯林斯英汉双解大词典》

It is important to keep in mind the fact that ROTs are useful only for rough estimating, but not for detailed analysis.

记住这样一个事实很重要，即ROT只对于粗略的估计有用，而对于详细的分析用处不大。

youdao

They were big,rough fellows. They had chosen me as the only 'Dutchman' -- as they called me -- to make them laugh.

VOA: special.2010.08.01

Just to repeat, yes, this is a very rough only method of looking at this change in prices, in relative prices between labour and nails.

FORBES: No, the Price of Nails, Not Adam Smith's Pins

But the rough is only marginally thicker than at some regular Tour events and winning the Players does not require the same level of skill, high-wire daring and mental endurance that winning a major does.

WSJ: Players Championship: The Major That Isn't Yet Major

But banks can make only rough guesses at the value of swaps and thus how much collateral their counterparties need to ante up.

FORBES: Magazine Article