How to use the window replacement cost estimator
- List each kind of window under Windows: a type or room, the count, the unit price and the install price each. The first row starts as an example of 10 windows.
- Add one-time extras for the whole job, such as permits, disposal or trim.
- Enter the sales tax rate for your area. It starts at 0, so nothing is assumed. Tick the box if tax also applies to installation and extras.
- Optionally add a cushion for surprises as a percent. Read the estimated total, the cost per window and the breakdown by window type. Use Copy, Print or CSV to keep it.
Formula
Line total = count x (unit price + install price each)
Sales tax = rate x units (or rate x units + installation + extras if ticked)
Subtotal = units + installation + extras + sales tax
Total = subtotal + cushion percent x subtotal
The calculator adds up the prices you enter. It does not know local prices or tax rules.
Ten windows at $450 plus $150 install
Ten windows at $450 each cost $4,500. Installation at $150 each is $1,500. Together that is $6,000, or $600 per window. With $200 of permits and disposal and a 7% tax rate on the units, tax is $315 and the total is $6,515.
If tax also applied to installation and extras, it would be 7% of $6,200, which is $434, and a 10% cushion on the new subtotal of $6,634 adds $663.40, for a final total of $7,297.40. Changing the tick box is a quick way to see how much the tax rule matters on your quote.
Collecting quotes you can compare
Window quotes come in different shapes. One company may give a single price per window including installation, while another separates the unit, the labor and the trim. Enter each quote the same way, as a unit price and an install price, so the totals can be compared line by line. If a quote gives one all in price, put it in the unit price and leave the install price at 0.
Check what each quote includes: removal and disposal of the old window, repair of the frame or wall, inside and outside trim, screens and any warranty. Costs that are missing from one quote often show up as extras later.
Planning the whole project
Window projects often reveal other work, such as rotted framing or damaged siding, which is the reason to add a cushion if you want one. The percent is your own choice and the tool does not suggest one.
Measure the openings before ordering: the rough opening calculator helps with the frame size, and the window blind size calculator is useful for coverings afterward. For the wider budget, the renovation budget planner tracks costs across rooms, and the DIY materials list builder gathers supplies.
Assumptions and limits
- Prices are the figures you enter. They are examples at first and are not price lists or regional costs.
- Sales tax is whatever rate you enter, with a default of 0. Whether installation is taxed depends on your area, so a tick box lets you test both.
- Rebates, tax credits and financing costs are not modeled.
- The cushion is a percent of everything before it, applied once.
Frequently asked questions
How do I estimate the cost to replace windows?
Get quotes, then enter the count, the price of each unit and the install price for each type of window. The tool multiplies, adds the extras and tax, and gives a total and a cost per window.
Should I include a cushion?
A cushion covers surprises such as rot behind old frames. The right percent depends on your home and how much risk you are comfortable with, which is why it is your own entry and starts at 0.
Is installation taxed?
That depends on where you live and the rules for the type of work. Tick the box to include installation and extras in the taxed amount and untick it to tax only the windows.
Can I mix different sizes and styles?
Yes. Add a row for each type, up to 12, with its own count and prices, and the totals combine them.