Name the expense and the date
A future car repair, move, tuition bill, or annual premium is easier to plan when it has a clear name and an approximate month. Start with the best information you have and update it when the estimate changes.
Divide the gap
Subtract what you already have from the amount you expect to need, then divide the remainder by the number of months available. If the monthly amount is too high, adjust the timeline, the scope, or the source of the money before the bill arrives.
Protect the emergency fund
A planned cost deserves a planned account. Keeping it separate from emergency savings makes it less likely that a predictable expense will consume money reserved for a genuine disruption.