I’m trying to write a Sci-Fi novel in one year and I’m wondering how many words I should write per week. I’m shooting for a total of ~90,000 words by the end of the year. In terms of when I can write I’ll say no Sundays, not till after 4pm on weekdays and all day from July through September. This will be my first novel and longest written work.
BEWARE THE PITFALLS:
Unless you need the deadline for motivation, I wouldn't be so rigid. Figure out how much time you can spare from your life, then cut that in half, and do that. Set writing time goals that are achievable and sustainable. Time is constant, but productivity (in the form of words) can be extremely variable depending on research, revisions, etc. You will resent your writing if you spend all your free time doing it. I personally was using writing as a kind-of therapy to work through the death of my parents (providing motivation), but I find it harder to give up free time now that I accomplished my goal.
Explain your goals to the important people in your life and get their buy-in. You won't get far if your (parent/husband/kids) are angry and resentful of your time demands. Most of those people love you and will understand, IF they get buy-in first. If I had followed my own advice, I would have had a happier family.
DON'T put off revisions (IMOHO). You will need to change the story as plot elements shift (especially if you don't have a perfectly fixed vision of the story). Those revisions affect the WHOLE story, and you will need to do ten times the amount of work rewriting ALL your story just because the events in chapter 3 changed and affect the rest of the novel. OR you will be unwilling to make the changes needed afterwards because of the amount of work involved to fix them.
Otherwise I think it's quite achievable. I did 127K words to beta-reader-ready state in about 13 months for my first novel while working full time.
It is not that simple. Do you want a very rough draft or a finished novel?
And it will depend on your experience and your process. So what is your writing background and knowledge of methods to do a novel?
Writing will not be able to be predicted in exact amounts as 'X' words/week. It is much harder to write all day than for an hour or two at a time. And more so when days in some weeks will be 4-5x as long than others considering the actual time available to write.
Abe Lincoln said that if he had an hour to cut down a tree he would spend 50 minutes sharpening his axe.
So how much time will you spend first on planning so you will not waste every so much very more time later with rewrites and detours down dead ends that you throw away? Do you have the ability to NOT edit while you go, but do that last? If not then plan to write a lot more words that end up in the trashcan.
If this is your first novel, I would suggest that you first plan it carefully so you know where the story goes and how it ends. Then be satisfied with finishing a decent novel at all whether you can do it in 6 months or two years. There are many writers who never finish a novel at all. There are many more bottom drawers full of unfinished mss by pantsers as well as too many by planners who gave up. Can you stick it out and not quit?
Anyway, to answer the question in the OP you will need, in my estimation as a paid professional writer, to write as many as 7000 to 15,000 words a week, on the average to end up with a 90k novel in a year, if you do it like so many new writers attempt; down to a low of 3500/wk if you are experienced and actually do it in only 6 months, or you could do it in 12 months with doing less than 2000 words/week.
Context: I easily write 1500 words , or more, at one sitting -- IF I have an idea what I need to say. As most of my published writing is relatively short, it does not need nearly as much planning or preparation as a long novel.
If I were to try a novel I would do sufficient planning so I know at least the way points on the journey from start to finish and then expect to write 3000-6000 words/week without any stress. To finish in a year I would expect to spend about 8-9 months planning, and then write for 3-4 months ending up with a good clean first draft ready for editing.