Garage Door Size Calculator — Size & Spring Specs
Recommended Door Size
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Estimated Door Weight
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Spring Recommendation
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Garage Door Sizing and Spring Selection Guide
Choosing the right garage door size starts with accurately measuring your rough opening. Standard single-car doors are 8 or 9 feet wide by 7 feet tall, while double-car doors are typically 16 feet wide by 7 feet tall. Oversized openings for RVs, boats, or commercial vehicles may require doors up to 10 or 12 feet tall. This calculator matches your opening dimensions to the nearest standard door size and estimates the door weight based on your chosen material.
Door weight is critical for selecting the correct spring system. Lightweight aluminum doors weigh about 2.5 pounds per square foot, steel doors about 3 pounds, insulated steel about 4.5 pounds, and solid wood doors up to 6 pounds per square foot. Doors under 150 pounds can use extension springs mounted on either side of the opening, while heavier doors should use torsion springs mounted above the door for smoother, safer operation. Insulated doors with polyurethane or polystyrene cores offer R-values between R-6 and R-18, making them worthwhile in attached garages or climate-controlled spaces.
Standard torsion springs are rated for approximately 10,000 cycles, which translates to roughly 7 to 10 years of typical residential use at 2 to 4 cycles per day. High-cycle springs rated for 25,000 to 50,000 cycles are available and recommended for frequently used doors. Spring replacement is one of the most dangerous DIY home repairs due to the extreme tension involved, so professional installation is strongly recommended whenever springs need to be adjusted or replaced.
Frequently Asked Questions
What is the standard garage door size?
Single car doors are typically 8 or 9 feet wide by 7 feet tall. Double car doors are 16 feet wide by 7 feet tall. RV or oversized doors can be 10-12 feet tall.
Torsion vs extension springs?
Torsion springs mount above the door and are safer, longer-lasting, and smoother. Extension springs mount on both sides and are cheaper but more dangerous if they break. Doors over 150 lbs should use torsion springs.
How often should springs be replaced?
Standard torsion springs last about 10,000 cycles (roughly 7-10 years of normal use). High-cycle springs rated for 25,000-50,000 cycles are available for frequently used doors.