Rough opening for 30 inch door: exact sizes, framing steps, and common pitfalls 📏

Planning a new interior door and wondering the rough opening for 30 inch door? Here’s the quick, pro-grade answer with a sizing table, framing steps, and how this relates to 3-0 rough door opening and rough opening for 30x80 door specs.

Key idea: Rough opening (RO) must be larger than the door unit to allow for the jambs, shims, and level/plumb adjustment.

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The fast answer (and why)

For a standard 30" × 80" interior prehung door (often written 2-6 × 6-8 or “rough opening for 30x80 door”):

• Typical RO width: 32"

• Typical RO height: 82½" (some manufacturers list 82"–82¼")

That extra space (≈ +2" width, +2–2½" height) gives you room to plumb, level, and shim the unit, and to account for finished flooring. 🪚

Pro tip: Always check the manufacturer’s sheet for your exact prehung unit—ROs can vary by ¼–½".

Table: common interior door sizes and rough openings

Nominal slab (W×H)	Trade size	Typical rough opening (W×H)	Notes
30" × 80"	2-6 × 6-8	32" × 82½"	Most common bedroom/bath size
28" × 80"	2-4 × 6-8	30" × 82½"	Small rooms/closets
32" × 80"	2-8 × 6-8	34" × 82½"	Wider passage
36" × 80"	3-0 × 6-8	38" × 82½"	ADA-friendlier width — this is the 3-0 rough door opening you’ll see on plans

RO height can be 82"–82½" depending on brand, threshold, and finished floor thickness

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Caution: Finished flooring (tile vs. carpet) and thresholds can change your target RO height. Leave headroom, then scribe the jamb legs to final floor.

How to frame the rough opening for 30 inch door (step-by-step)

1. Lay out the opening: Mark 32" clear between king studs for a 30" door.

2. Build the jack studs: Nail jack studs to the king studs, leaving 32" between jacks.

3. Set header height: For an 80" slab prehung, set the header so finished RO height is ≈82½". Use cripples above the header as required.

4. Check plumb and square: Use a level on jacks and check diagonals of the RO; aim for ≤⅛" difference corner to corner.

5. Sheath and prep: Keep the RO clean; don’t crowd it with drywall screws or proud nails that will catch the jamb.

6. Install the unit: Center the prehung, set the hinge-side jamb dead plumb, shim at hinges and latch, then fasten through shims.

7. Gap & reveal: Target a consistent 1/8" reveal around the slab; adjust with shims before trimming.

Pro tip: Hang the door off the hinge side first. If the hinge jamb is perfect, the rest of the reveals fall into place with minimal fuss. 🙂

FAQ

In one sentence: what’s the rough opening for 30 inch door? Typically 32" × 82½" for a prehung 30" × 80" interior door, allowing for shims and leveling.

What if my manufacturer says 82" instead of 82½"? Follow the spec for your exact unit; some frames, thresholds, and flooring stacks reduce the required RO height.

Does wall thickness change the RO? No—RO width/height stay the same. Wall thickness (2×4 vs 2×6) changes the jamb depth (e.g., 4-9/16" vs 6-9/16"), not the RO.

Can I reuse an old RO for a new door? Yes, if it measures correctly and is plumb/square. Plane/scribe jambs or adjust shims to correct minor issues.

Is the 3-0 rough door opening the same formula? Yes—add about +2" width and +2–2½" height to the 36" × 80" nominal, landing near 38" × 82½".

Rough opening for 30 inch door: field checklist

• Width at three heights: 32" ± ⅛"

• Height both sides: 82"–82½" (consistent to within ⅛")

• Plumb: hinge-side jack within 1/16" over 6' level

• Square: diagonal measurements within ⅛" of each other

• Dry run: test fit the prehung before painting or trimming

Field note: If finished floor isn’t down, block under the jamb legs to mimic the final floor height; then you won’t have to trim the door later.

Conclusion

The short version: the rough opening for 30 inch door is 32" × 82½" in most residential builds, with small variations by brand and flooring. Use the table above, confirm the rough opening for 30x80 door on your spec sheet, and remember the same +2"/+2–2½" rule when you read a 3-0 rough door opening on a plan. Get the opening plumb, square, and consistent—and your trim will go on fast and clean. ✅