'duration will be' is correct and usable in written English.
You can use it to describe a timeframe for something in the future. For example, "The duration will be two weeks."
The duration will be at least 14 days.
Hard bargaining over price and duration will be essential.
Mean follow-up duration will be 4 years.
The mission duration will be one Martian year.
Rather, its duration will be directly linked to the jobs picture.
To obtain the optimal solution, optimizing sensing duration and transmission duration will be first performed separately.
Its duration will be nearly two minutes longer at peak: four minutes and 28 seconds vs. two minutes and 41 seconds.
The accumulation of cases and follow-up of greater duration will be necessary to precisely confirm the efficacy of this new technique.
Ultimately, controlled feeding studies of at least 6 to 12 months duration will be needed to answer this fundamental question in nutrition.
"The period of transition" and its "form and duration will be determined later," said the declaration, which was drafted and signed after senior officers met with the joint chief of staff on Saturday.
In reality, the duration will be affected due to parents' concern for adult children and the money flows between them.
