# The estimated length of a future event is / will be ... (tense)?

Say, I am travelling in Thailand next month, and I estimate that it will take me 1 week for the travel.

What tense should I use to describe the estimated length of the travel : "The estimated length of the travel is (present tense) / will be (future tense) 1 week." ?

Why I am asking this question is that I think the proper tense to be the future tense because the travel (including its length) is a future event. An example from the Internet: "... the estimated population will be 1.5-1.8 billion in 2050 ...", however, I have found on the Internet that the present tense may also be possible, for example, "What is (present tense) the estimated length of the hearing, for which the hearing dates will be fixed)？"

The estimate in question already exists (one week), so there is nothing wrong with

A The estimated length of the actual travelling is 1 week.

This is in line with

A' My estimate for how long the actual travelling will take is one week.

Note that this variant (justified here as you say "I estimate that ... ") comes across as less of an arrogation; 'my' estimate may be way out. I prefer present tense here, and the concession that my estimate is not peer-reviewed and certainly not guaranteed accurate.

..........................

But, for some reason, I prefer future tense in

B ... the estimated population will be 1.5-1.8 billion in 2050 ...,

even though again the estimate already exists. This is probably because this is an idiomatic (over 60 000 Google hits for "estimated population will be") if not strictly logical shortening of

B' It is estimated that the population will be 1.5-1.8 billion in 2050 ...

or

B" Present estimates are that the population will be 1.5-1.8 billion in 2050 ...

[bolding just to highlight tense] etc.