A header size chart shows the minimum structural member required to span an opening in a bearing wall. Headers carry the load from framing above the opening — windows, doors, and garage bays — down to the jack and king studs on each side. Sizing depends on the span width, story load condition, and whether the wall is exterior or interior bearing.
Header Size Lookup
Clear span between supports
Stories supported above
Bearing wall type
Full Header Size Reference Table
IRC R602.7 — Bearing wall headers, solid sawn lumber (Douglas Fir-Larch No. 2 or better)
| Span | Load Condition | Exterior Bearing | Interior Bearing |
|---|
Engineered Lumber (LVL) Header Alternatives
LVL headers can span wider openings with less depth — ideal for tight header spaces
| Opening Span | Solid Lumber (2-Story Exterior) | 1-3/4" LVL Replacement |
|---|---|---|
| Up to 4' | Double 2×4 | 1-3/4" × 3-1/2" LVL |
| 4'–6' | Double 2×6 | 1-3/4" × 5-1/2" LVL |
| 6'–8' | Double 2×8 | 1-3/4" × 7-1/4" LVL |
| 8'–10' | Double 2×10 | 1-3/4" × 9-1/4" LVL |
| 10'–12' | Double 2×12 | 1-3/4" × 11-1/4" LVL |
| 12'–16' | Engineered design required | Double 1-3/4" × 11-1/4" LVL or beam |
| Over 16' | Engineer design only | Custom beam per engineer |
Code Reference Notes (IRC R602.7)
Assumptions in This Table
- • Lumber species: Douglas Fir-Larch #2 or Hem-Fir #2
- • Roof load: 20 psf dead + 20 psf live (40 psf total)
- • Floor load: 10 psf dead + 40 psf live (50 psf total)
- • Wall type: Standard 2×4 or 2×6 platform framing
- • Double headers: Two members nailed together throughout
When to Get an Engineer
- • Spans over 12 feet in bearing walls
- • Heavy snow loads (over 30 psf ground snow)
- • Unusually wide tributary width above header
- • Removing an existing wall or changing loads
- • Any span over 16 feet (requires engineered design)
- • Local amendments may require engineer stamp earlier
Disclaimer: This chart is for reference and planning purposes only. Always verify header sizes with your local building official and consult a licensed structural engineer for final design. Local jurisdictions may adopt amendments to the IRC that affect minimum header sizes.
How to Use the Header Size Chart
This free structural header size chart helps you quickly identify the minimum lumber size needed for window and door openings in residential bearing walls. Whether you're framing a new home, adding a window, or replacing a door, selecting the correct header prevents deflection, settling, and structural failure over time.
Step 1: Measure the Clear Span
The span is the clear horizontal distance between the jack studs (trimmer studs) that support the header. This is the rough opening width — not the window or door unit size, which is typically 1 inch smaller. For a standard 36-inch door, the rough opening is about 38 inches and the header span is measured jack-stud to jack-stud.
Step 2: Identify the Load Condition
The load condition tells you how many floors and the roof are bearing on this header. A 1-story header is below a roof only — typical for the top floor of a house or a single-story structure. A 2-story header is on the first floor, carrying a second floor's framing plus the roof — the highest load category. A floor-only condition applies to interior headers that carry only a floor deck above, with no roof load path through that wall.
Step 3: Select Exterior or Interior Bearing
An exterior bearing wall runs along the perimeter of the building and carries both the roof and floor loads from above. It typically requires a larger header size chart member than an interior wall. An interior bearing wall carries loads from the floor above but typically has a smaller tributary width. Non-bearing partition walls do not require structurally sized headers.
Step 4: Read the Minimum Header Size
Use the lookup tool or find your span row in the reference table. The result shows the minimum solid sawn lumber header (e.g., Double 2×10) and an equivalent LVL alternative. "Double" means two members nailed together face-to-face. For a standard 2×4 wall, a double header fills the 3-1/2" wall depth. For a 2×6 exterior wall, add a 1/2" plywood spacer between the two members to fill the 5-1/2" depth.
Understanding LVL Header Alternatives
LVL (Laminated Veneer Lumber) is an engineered wood product made from thin wood veneers bonded with adhesive. It is stronger and more consistent than solid sawn lumber, making it ideal for wide spans and situations with limited header depth. A single 1-3/4" LVL can replace a doubled 2× solid header in many cases, though you must verify with the manufacturer's span table for the specific product and loading. LVL is also more resistant to warping, twisting, and checking compared to green or air-dried dimensional lumber.
Building Code Reference: IRC R602.7
The International Residential Code (IRC) Section R602.7 provides prescriptive header size tables for wood frame construction. These tables assume standard load conditions, typical lumber species (Douglas Fir-Larch or Hem-Fir No. 2), and standard 2× platform framing. Most US states adopt the IRC with local amendments. Always confirm requirements with your local building department — some jurisdictions require a structural engineer's stamp for headers over a certain span, regardless of the prescriptive tables.
FAQ
Is this header size chart free to use?
Yes, this structural header sizing chart is completely free. It runs entirely in your browser — no signup, no account, and no data is sent to any server. Bookmark it for quick reference on the job site.
Is my data private when using this tool?
Yes. All lookups happen locally in your browser. Nothing is transmitted to any server, and the tool works offline once the page has loaded.
What building code do these header sizes follow?
These sizes are based on IRC Section R602.7 (International Residential Code), Table R602.7. This is the model code adopted by most US states and municipalities for single-family and two-family residential construction. Always verify with your local jurisdiction, as local amendments may apply.
What is the difference between a 1-story, 2-story, and single-floor load?
The load condition determines how much weight the header must carry. A 1-story header supports only the roof above (roof load only). A 2-story header supports a floor plus the roof above — the heaviest load. A single-floor header (interior) supports only one floor deck with no roof load, requiring a smaller member.
When should I use an LVL header instead of dimensional lumber?
LVL (Laminated Veneer Lumber) is preferred for wide spans over 8 feet, situations with limited header depth (low ceilings), and when you need consistent strength without checking for knots. A single 1-3/4" LVL can often replace a doubled solid sawn header, saving depth in the wall assembly. LVL is also more dimensionally stable in wet conditions.
What is a double header versus a single header?
Most residential headers are built as two members nailed together (e.g., Double 2×8) to match the 3-1/2" width of a standard 2×4 stud wall. For 2×6 exterior walls you may use two members plus a 1/2" spacer. A single header is less common and typically only acceptable for small spans in non-bearing walls, or when using thick engineered lumber.
Do I need a header in a non-bearing wall?
In a non-bearing wall, headers are not structurally required to carry a load, but a minimal header (typically a flat 2×4 or single 2×4 on edge) is still installed to provide a nailing surface for trim and to frame the rough opening. The sizes in this chart apply to bearing walls only.
Can I use a larger header than required?
Yes. Using a larger header than the minimum required is always acceptable and provides a safety margin. On complex projects or wide spans, engineers often specify members larger than the IRC prescriptive table minimum. Never use a member smaller than the table requires for the given span and load.