Walk the space first
Never bid an office from a phone call. Walk it, measure or estimate the cleanable square feet, count the restrooms and note anything that slows the work: lots of desks, glass, a kitchen, carpet against hard floor.
Hours from a production rate
A production rate is how many square feet one cleaner covers in an hour. Light offices are often 2,500 or more; restroom-heavy or medical spaces 1,200 to 1,800. Divide the square feet by your rate to get hours per visit, and round up to the quarter hour.
Your own rate matters more than any rule of thumb. Time your first few contracts and use what you measured.
Cost per visit
Multiply the hours by the wage, plus payroll costs if you have staff (the calculator starts at 20%; use 0% and your own rate if you work alone). Add supplies (about 3% of labour to start) and overhead (about 25% of labour and supplies).
Price from margin
Price per visit = cost per visit / (1 − target margin). With a 40% target margin, a $100 cost becomes a $167 price. Monthly price = price per visit × visits per week × 4.33.
The calculator flags any bid where the gross margin falls under 45% or the monthly price is under your monthly floor.
Write the schedule into the bid
Say what happens every visit and what happens weekly or monthly. The office checklist is a starting point.