Doors and windows calculator
Counted, not measured. Openings price per unit, with the trim and hardware that follow each one.
Doors & windows
Counted, not measured. Openings price per unit, with the trim and hardware that follow each one.
Waste does not apply to counted units. Order one spare hinge set per five doors.
$1,482
19.0 units of hollow-core door slab at $78.00 / unit
Free. No signup. The quantities carry over as line items.
How this doors & windows calculator works
Doors and windows are counted, not measured. Each one carries casing and hardware behind it, which is where the real per-opening cost lives.
The formula
units = doors + windows · casing = units × trim per opening · hardware sets = doors
Assumptions and defaults
| Casing per opening | 17 ft |
| Waste | not applied to counted units |
| Hardware | one hinge set and lockset per door |
Pro tips
Order one spare hinge set per five doors. They get damaged, mismatched and lost between delivery and hanging.
Prehung units cost more than slabs and save more than the difference in labour, unless you are reusing existing jambs.
Measure every rough opening before ordering windows, not just one of each type. Builders are not as consistent as their plans.
Common questions
How do I price doors and windows?
Per unit, with casing and hardware as their own lines. This calculator counts openings and works out the casing footage behind them.
How much casing per door?
About 17 linear feet for a standard interior door with both sides cased. A window is similar once you include the apron and stool.
Slab or prehung doors?
Prehung for new openings — jamb, hinges and swing are set for you. Slabs only when the existing jamb is good and you are matching a swing.
Why does waste not apply here?
Because you cannot buy 8.8 doors. Counted units order exactly; the spares you carry are a stocking decision, not a waste percentage.