Free Window Replacement Cost Calculator (+ Guide)

What is a window replacement cost calculator?

A window replacement cost calculator adds up every cost of new windows, from the installer's quote to the trim and finishing inside.

It shows the total with a contingency, the cost per window and what's left of your budget.

How it works

The cheapest of your quotes goes in the total, next to the costs it doesn't cover.

Which windows save energy

ENERGY STAR says certified windows lower household energy bills by an average of up to 13% nationwide when they replace single-pane windows.

Look for the label made for your climate zone, since the ratings differ from north to south.

The IRS energy efficient home improvement credit paid up to $600 a year for qualifying windows, but only for work done through December 31, 2025.

Lead paint in homes built before 1978

The EPA's Renovation, Repair and Painting Rule has applied since April 22, 2010.

• Any firm you pay for work that disturbs lead-based paint in a home built before 1978 must be EPA- or state-certified
• It must use certified renovators who follow lead-safe work practices
• The rule generally doesn't cover homeowners working on their own home, unless they rent it out, run a child care center in it or flip houses

So in an older home, ask each contractor for their lead-safe certification before you compare prices.

How to compare contractors' quotes

The Federal Trade Commission gives this advice before you hire anyone.

• Hire only licensed and insured contractors, and check the license with your state or county
• Get several written estimates, each with the work, the materials, the completion date and the price
• Don't automatically pick the lowest bid, and ask why if the estimates differ a lot
• Get a written contract with the contractor's license number and the start and finish dates
• Never pay the full amount up front, and make the final payment only when the work is done

It also warns that a contractor who asks you to get the permits, or who only takes cash, may be running a scam.

How much contingency to add

A contingency is money set aside for what you find once the walls or the ground are open.

HUD requires one on its 203(k) renovation loans: 10% to 20% of the repair costs on a home 30 years or older, and at least 15% when the utilities don't work.

On a newer home, it's up to the lender, to a maximum of 20%.

A worked example

Here's the example the calculator loads: 12 windows with three quotes of $14,400, $16,800 and $13,200, plus interior finishing and the permit.

The cheapest of the three quotes is $13,200, $3,600 less than the dearest. Your other costs add $850, so the window replacement comes to $14,050 before the contingency.

A 10% contingency adds $1,405, for a total of $15,455. That's $1,287.92 per window, and $2,545 left of a $18,000 budget.

Mistakes to avoid

These are the slips that come up most.

• Comparing quotes for different windows or different installs
• Hiring an installer for a pre-1978 home without asking for lead-safe certification
• Counting on the federal window credit for work done after 2025

Who is the window replacement cost calculator for?

It's for anyone replacing a few windows or every one, and these tools help around it.

• Home renovation calculator – for a bigger project
• Electricity cost calculator – for running costs
• Home equity loan calculator – if you borrow for it

Compare the cost per window for the same windows, and the cheapest quote is a real saving.