Plan words per day to hit a deadline.
Deadline planning works from what is left, not the total. Subtract the words already written, divide by the days remaining and you have the daily quota; dividing that by your drafting rate converts it into hours at the desk, which is the figure you can actually schedule. Recompute after every session — the quota falls when you beat it and climbs when you miss, and watching it drift is a far earlier warning than watching the deadline approach.
Words per day to hit a deadline
Words per day = (total words - words written) / days remaining; hours per day = words per day / drafting rate
Measure it rather than guess. Time one honest session and divide words by hours — 500 to 1,000 words per hour is typical for prose you have already outlined, and considerably less for technical or researched writing.
No. Leave the last 15% to 20% of the days for revision and formatting, because a draft finished on the deadline is not a submission. Enter the earlier date as the deadline and treat the difference as revision time.
Because every day you write less than the quota, the same remaining words divide across fewer days. That compounding is why the figure is worth recomputing after each session rather than at the start.