Door Calculator

Estimate door quantity, hardware, and total replacement cost.

Estimate door quantity, hardware, and total replacement cost.

Door Material Guide

Selecting the right doors affects your home’s appearance, sound insulation, security, and energy efficiency.

Type Cost Best For Lifespan
Hollow Core $50-150 Interior, closets 20-30 yrs
Solid Core $150-500 Bedrooms, offices 30+ yrs
Fiberglass (ext) $200-600 Front entry 20-30 yrs
Steel (ext) $150-400 Security, garage entry 20-30 yrs
Solid Wood (ext) $500-2,000 Premium entry 30+ yrs

Frequently Asked Questions

How much does a new door cost?
Interior hollow core: $50-150. Interior solid core: $150-500. Exterior fiberglass: $200-600. Exterior steel: $150-400. Solid wood entry: $500-2,000+. Installation adds $100-300 per door.
What is a standard door size?
Standard interior doors: 80 inches tall × 28-36 inches wide (most common is 80×32 or 80×36). Standard exterior doors: 80×36 inches. Double entry doors: 80×72 inches. Custom sizes are available at higher cost.
What is the difference between hollow core and solid core doors?
Hollow core doors have a cardboard honeycomb interior — lightweight and inexpensive. Solid core doors have a composite or wood interior — heavier, better sound insulation, more durable, and required for fire ratings.
How do I measure for a replacement door?
Measure the width and height of the existing door (not the frame). For pre-hung doors, measure the rough opening: width between studs and height from floor to header. Standard rough openings are 2 inches wider and taller than the door.
Do I need a pre-hung or slab door?
Pre-hung doors come with the frame attached — ideal for new openings or frame replacement. Slab doors are just the door panel — used to replace a door in an existing frame. Pre-hung is easier; slab is cheaper.
What is the best exterior door material?
Fiberglass: best overall (durable, insulating, low maintenance). Steel: most secure and affordable. Wood: most beautiful but requires maintenance. Fiberglass can mimic wood grain without the upkeep.
How long does door installation take?
Pre-hung interior door: 1-2 hours. Slab door (re-hang): 1-3 hours. Exterior pre-hung: 2-4 hours. Entry door with sidelights: 4-6 hours. Times vary with experience and complexity.
What R-value should an exterior door have?
Exterior doors should have an R-value of 5-6 minimum. Insulated fiberglass and steel doors typically have R-5 to R-15. Wood doors range R-2 to R-5. Higher R-values mean better energy efficiency.
Do I need a storm door?
Storm doors protect entry doors from weather, improve insulation, and allow ventilation. They’re most beneficial in extreme climates. Skip if you have a protected entryway or a high-quality insulated entry door.
How many doors does an average house have?
An average 3-bedroom house has 12-18 doors: 8-12 interior passage doors, 1-2 exterior doors, 1-2 closet doors, and possibly a garage entry door. Larger homes may have 20-30+.