I created a writing tracker for word counts. It's based on 5 days of writing a week, but it adjusts goals if you write more or fewer days. You just enter your book's word goal and end goal date. Then enter your end-of-day word count and date, and it does the rest. It will tell you how many words you need to write per day to reach your goal date (which you can adjust). I know it definitely works in Excel and Zoho Sheet (which has a free online profile). It should also work in Mac Numbers and Google Sheets, but I haven't checked those yet.