Lintel Beam Size Calculator
Estimate preliminary lintel beam size over door, window, garage, and masonry openings using clear opening, bearing length, wall height above, wall material, roof or floor load, lintel type, deflection, and bearing checks.
⚙Door and Window Lintel Presets
📏Lintel Opening Inputs
Preliminary Lintel Check
Calculation Breakdown
🧱Selected Lintel Material Grid
📊Opening Load Reference
| Opening Condition | Typical Clear Opening | Common Load Above | Deflection Target |
|---|---|---|---|
| Interior nonbearing door | 2 ft 8 in to 3 ft | Framed wall only | L/240 to L/360 |
| Exterior window with veneer | 3 ft to 6 ft | Masonry triangle plus roof | L/360 to L/600 |
| Patio door header | 5 ft to 8 ft | Wall and roof load | L/360 |
| Garage door header | 8 ft to 18 ft | Roof, floor, or braced wall | L/360 to L/480 |
| Storefront masonry lintel | 6 ft to 12 ft | Brick, block, stone, or concrete | L/480 to L/600 |
💪Lintel Material Reference
| Lintel Type | Typical Modulus E | Best Fit | Watch Check |
|---|---|---|---|
| SPF or Douglas Fir header | 1.4E to 1.6E psi | Short wood framed openings | Deflection and end bearing |
| LVL or PSL built-up header | 1.9E to 2.0E psi | Wide doors and garage openings | Connection between plies |
| Steel angle lintel | 29.0E psi | Brick veneer support | Rotation and corrosion coating |
| Reinforced concrete lintel | 3.6E psi | Concrete and masonry walls | Rebar cover and cracking |
| Reinforced CMU bond beam | 2.0E psi | Block walls above openings | Grout, rebar, and bearing |
📏Bearing Length Guide
| Support Material | Common Minimum Seat | Bearing Stress Basis | Calculator Use |
|---|---|---|---|
| Wood jack stud or trimmer | 1.5 in to 3.5 in | Compression perpendicular to grain | Enter actual contact length |
| Brick or stone masonry | 4 in to 8 in | Masonry bearing capacity | Use shortest masonry seat |
| CMU block jamb | 6 in to 8 in | Grouted cell or bond beam bearing | Do not count hollow shell only |
| Concrete wall or pilaster | 4 in to 8 in | Concrete bearing surface | Verify edge distance and cover |
| Steel post or plate | Plate by design | Local web or plate bearing | Use plate length in contact |
📋Common Lintel Size Reference
| Preliminary Lintel | Common Opening Range | Typical Wall Load | Comment |
|---|---|---|---|
| Double 2x8 wood header | 3 ft to 5 ft | Light roof or partition | Short span only |
| Double 2x12 wood header | 4 ft to 8 ft | Roof load above | Check sag at patio doors |
| Two 11-7/8 in LVLs | 6 ft to 12 ft | Roof or floor load | Common residential header |
| Steel angle 4 x 3-1/2 x 5/16 | 3 ft to 6 ft | Brick veneer | Needs corrosion protection |
| 8 in reinforced bond beam | 3 ft to 6 ft | CMU wall above | Depends on grout and rebar |
| Precast concrete lintel | 3 ft to 8 ft | Masonry or concrete wall | Use product S and I values |
💡Lintel Sizing Tips
The framing sits on the headers. But the framing sits on the headers. If you want to open up a floor plan by removing one of those walls inside your home, you’re not taking out just the stud work, you’re redistributing weight from a wall that was supporting the roof to a new beam. That beam has to hold the weight without cracking the drywall overhead or worse (without sagging).
So how do most people start? They start by measuring the width of opening. That’s a decent starting point, but it doesn’t address the load. The load represent all of the stuff that would be above the beam. This include the joists, which might have snow on them and whatever sheathing sits atop the joists. It also includes weight of the beam itself.
How to Choose the Right Beam for Your Home
Once you input your dimensions and your material choices, the calculator takes care of all that for you. So you can stop guessing about how much dead load is added by your brick veneer. Know what you are measuring. A light weight wood stud wall with an open door will take less of a load than a solid brick front with exact same size opening. Why? Because masonry is unforgiving and heavy, it doesn’t adjust to your budget.
And if the span is large such as a wide storefront window or a garage door, this is where deflection becomes a big issue. In this case a header may not snap but it could bend so far that it cracks all the finishes surrounding it. That’s when deflection comes into play. There are deflection limits in tool such as L/360 or L/480. These are ratios to make sure the beam stays stiff, the windows won’t get stuck in their frames. The doors will close shut by themselves.
The answer depends a lot on which material is chosen. We are comfortabley working with wood and we know what it does. Wood expands and contracts based off relative humidity. Steel is strong but rigid. If wet, it must be detailed carefully to avoid corrosion. Concrete is tough. Unfortunately concrete weigh a ton and must be reinforced with rebar for tensile applications.
Not all of this means that more wood is better. You cannot just pile up thicker pieces of lumber; at some point, it’s too big to install easily. Manufactured components like glulam and LVL provides the best of both worlds. These engineered products deliver improved strength for their weight. The chart below shows where various materials matches with spans and type of walls.
The one common error is on the side of bearing length. Lintel ends require a good seat. On masonry it is usually four inches. Longer is better if possible. Where does the beam push its load down and how? The load goes down through floor structure or down into the foundation. Crushed or split support material result from insufficient bearing length. The calculator covers that. It will never let the reaction force at either end be more than what the material can handle.
It takes into account wall height above the opening. It limits the masonry load at a forty-five-degree arch angle. This is a typical engineering assumption, that keeps us from overestimating the weight of the wall just above the lintel. This is the depth of the tributary. This is the span of the floor or roof that sits atop the header. The wider the roof, the greater the load per foot of beam. If you live in a heavy snow area, this makes the difference between an acceptable design and a significant increase in load.
Ten or twenty percent design reserve will help account for variation in material quality. It also accounts for unforeseen loads. It is a small buffer but it is important for safety when designing structures. The tool will give you a preliminary size. It is not a building permit. Only a professional can check your final design against local codes that vary by region and change over time. What passed for code in your neighbor’s house five years ago may be outdated now.
Keeping the roof up is one thing, but keeping the roof level is another. If a lintel is big enough for the job you don’t notice it until it’s too late. Then there are door jambs and cracked plaster. These are all the result of getting the size wrong the first time around. Not so now. Now it’s neat and solid looking. Now it’s done right. Now the math is something you could of did yourself.
Running the numbers is easy. Understanding what they mean takes judgment. Make sure you take time to enter in correct data. Confirm the load. Double check the bearing. The house will thank you later.
