If you do a quick Google search you’ll find lots of calculators that will let you estimate the cost of installing or replacing your vinyl siding.
The formulas are based on square footage and number of floors, but when it comes to the cost of vinyl siding, more than those items comes into play.

Here are 2 items that can affect directly the costs of your project:

– What’s on your house right now?
Depending on the type of siding currently on your home, you may need additional labor or materials.
If your home can be “sided over”, then you can save on removal costs.
Wood siding can be sided over with foam insulation and then vinyl.
If you’re replacing vinyl with vinyl, however, the old vinyl will need to be removed before the new can be installed.

– What’s under your siding?
Perhaps the most difficult cost to factor in is the condition of what’s under your siding.
It’s probably been a long time since you noticed, but that doesn’t mean water hasn’t snuck under there and caused rot or damage.
It’s not always obvious from leaks in the house either, so you probably won’t know whether you need remediation until after the existing siding is removed.
Water damage can require carpentry work, which leads to more materials and labor. Plus, if the substrate material is damaged, that may need to be replaced too.
Since it’s impossible to know what’s under the siding until you look, you may want to budget a little extra just in case you find one these surprises.