Order the wrong handing and the prehung door that just arrived on the curb either swings into a wall, blocks a light switch, or opens the wrong way for traffic flow. Knowing left handed vs right handed door rules before you check out at Home Depot or order custom from Masonite saves a restocking fee, a return trip, and sometimes a four-week lead time. The test takes ten seconds once you understand the convention used across the US building industry.
The Standard US Handing Test
Stand on the side of the door that swings toward you — the side where the door opens into the room you are standing in. Then look at which side the hinges are on:
- Hinges on your left: it is a left-handed door.
- Hinges on your right: it is a right-handed door.
That side — the side the door swings toward you — is sometimes called the “pull side” or the “inswing side.” Manufacturers like Therma-Tru, Jeld-Wen, and Masonite use this convention on every order form. If you skip the pull-side rule and just stand on a random side, you will flip the answer half the time.
Why the Distinction Matters
Prehung doors come with the hinges already mortised into the jamb and the strike plate cut on the opposite side. You cannot just flip a prehung door upside down to change handing — the door slab itself has the latch bore drilled on one specific side, and the lock face is mortised accordingly. Buying the wrong handing means either returning a 80-pound assembly or paying a carpenter $120 to $200 to re-mortise everything on site.
For slab doors with no jamb, you have a little more flexibility because you can drill new hinge mortises. Even then, the existing latch bore and lock mortise force the handing.
Inswing vs. Outswing
Handing is only half the picture. The other variable is whether the door swings into the room (inswing) or out of it (outswing). Most interior doors and front entry doors in the US are inswing. Outswing is common for:
- Back doors in hurricane-prone coastal zones
- Closets where the inswing would block the contents
- Mechanical or utility rooms with limited floor space
- Storm doors and screen doors
The handing test above assumes inswing. For outswing doors, you stand on the side the door swings toward you — which is now the exterior or hallway side — and use the same hinge rule.
A Faster Field Trick
If you already have a door installed and want to match it, stand with your back to the hinges. The hand you would use to push the door open tells you the handing: push with your right hand, it’s a right-handed door. Push with your left, it’s left-handed. This is the trick most framing carpenters use because they almost always think about doors from the hinge side first.
One more sanity check — look at where the doorknob ends up. A right-handed door has the knob on the left side as you face the pull side, because the latch is opposite the hinge.
Lock and Hardware Implications
Most modern residential deadbolts and knob sets are reversible. Schlage B60, Kwikset 660, and Baldwin Prestige all ship with instructions for flipping the latch bevel to suit either handing. Commercial mortise locks and lever handles with a defined “up” position are not reversible — you order the lock specifically as LH or RH. If you are buying a Baldwin or Emtek mortise lock for an entry door, getting the handing wrong typically means a $80 to $180 special order replacement.
Single-cylinder smart locks like the August Wi-Fi Smart Lock and the Schlage Encode auto-calibrate during setup, so they work with either handing without configuration.
Door Hand Conventions Outside the US
Canada follows the same convention as the US. The UK and much of Europe use the opposite rule — they stand on the side the door swings away from you. If you are ordering from a European manufacturer like Rubinet or buying a door from an architectural salvage yard with imported stock, ask the supplier which standard their paperwork uses. The simplest fix: send a phone photo from the inswing side with the hinges visible.
Common Mistakes Before You Order
Three errors account for almost every wrong-handing return at the lumber yard:
- Standing on the wrong side. Always face the pull side first, then check the hinges.
- Confusing handing with which way you walk through. The room you enter does not determine the handing — the hinge side does.
- Assuming a closet door matches the bedroom door. Many builder-grade homes use opposite handing for the closet specifically so the doors do not collide.
Before you place an order, draw the rough opening on paper, mark the hinge side and latch side with the door swinging in, then walk the drawing through with a partner. Spending two minutes on a sketch beats unloading a 36-inch prehung exterior door from the truck only to discover it swings the wrong way.
When You Genuinely Need Custom Handing
Older homes with non-standard rough openings sometimes force a swap. If a radiator, vent, or staircase blocks the natural swing, ordering the opposite handing is cheaper than relocating the obstruction. Custom interior doors from Simpson or TruStile usually carry no upcharge for handing — you just specify it on the order. Exterior doors with sidelights or transoms may add $60 to $120 to swap because the frame components are not symmetrical.
Once you internalize the pull-side hinge test, the left handed vs right handed door question stops being intimidating. You can spec a whole house of doors in fifteen minutes with a notepad and a tape measure. Many lumber yards will also stamp a small LH or RH on the jamb in pencil at the order desk so the carpenter can confirm the handing once the door arrives on site.
