"an idea of when" is correct and usable in written English.
You can use it when you want to refer to a possible or suggested time frame. For example, "I have an idea of when the project should be completed."
"That'll give me an idea of when I can be ready".
"He was a wreck, he really was, because he likes to have an idea of when he's pitching and just lock in and get in the zone".
The minister also recently suggested that people should be given an idea of when they might die in order to help them plan their finances for retirement.
The plan, drawn up at the government's order, is meant to give residents evacuated from the area around the plant an idea of when they might be able to return home.
This involves no physical effort, but rather watching some free runners on the screen and concentrating on my breathing to get an idea of when I might be focused enough to try the game.
INSIDE PITCH The injured reliever Brian Bruney tossed a 30-pitch bullpen session Sunday and said he was finally able to throw without pain, though he still did not have an idea of when he might return.
"There is an idea of termination when you have a lifetime achievement," said the Bronx-born Mr. Azenberg — Manny to everyone in the theater world.
It's essential to understand the local city laws or have an idea of them when first arriving.
He said there was more work to be done and, when the court meets again on 4 June, they will have a better idea of when a trial can be held.
We were able to make sure she was healthy and perform the necessary scans to give her an accurate idea of when her baby would be born.
By entering search queries related to your nonprofit into the tool, you can get an exact idea of when and how much people are searching.
