Formula used
| Calculation | Formula |
|---|---|
| Horizontal projection | P = L × cos(θ) |
| Vertical drop | D = L × sin(θ) |
| Sloped awning length | L = P ÷ cos(θ) |
| Installation angle | θ = arctan(D ÷ P) |
| Solar projection | P = (Hm − Ht) ÷ tan(α) |
Here, P is projection, L is sloped length, D is drop, θ is pitch angle, and α is solar altitude.
How to use this calculator
- Select the calculation mode that matches the known measurements.
- Choose one unit and enter every length using that unit.
- Enter the awning angle or solar altitude when required.
- Add installation clearance, overhang, and a safety margin.
- Enter arm and space limits to activate planning warnings.
- Add candidate projection sizes for a direct comparison table.
- Calculate, review the diagram, and export the result.
Example data
| Input | Example value | Purpose |
|---|---|---|
| Sloped awning length | 2.20 m | Defines the fabric or arm length. |
| Installation angle | 20° | Controls projection and vertical drop. |
| Clearance | 0.10 m | Adds room for practical installation. |
| Fabric overhang | 0.05 m | Adds useful front-edge coverage. |
| Safety margin | 5% | Reduces under-sizing risk. |
| Arm limit | 3.00 m | Checks hardware extension limits. |
Awning projection planning guide
An awning projection is the horizontal distance from the mounting surface to the front edge. It is not always equal to the fabric length. A pitched awning uses a longer sloped length.
The installation angle affects both shade and drainage. A shallow pitch gives more horizontal reach. A steeper pitch creates more vertical coverage.
Start with reliable site measurements. Record the mounting height, opening height, available depth, and any obstacles. Include lights, doors, gutters, signs, and nearby structures.
Retractable awnings also have mechanical limits. Arm geometry, cassette design, and fabric tension can restrict usable projection. Manufacturer instructions should control the final selection.
Solar shading changes during the day. It also changes by season, latitude, wall orientation, and local obstructions. Generic solar presets are useful only for early planning.
For a solar calculation, use a verified solar altitude angle. Subtract the target shade height from the mounting height. Divide that difference by the tangent of the solar altitude.
Clearance and overhang can prevent under-sizing. The calculator adds both values after the base geometry. A percentage safety margin can provide additional planning room.
The nearest standard size is selected at or above the recommendation. This approach favors adequate coverage. Confirm that the selected size still fits the installation space.
Vertical coverage combines geometric drop, front drop, and valance depth. The percentage is only a simple opening comparison. Wind and sunlight can still enter from both sides.
A fixed awning may use different pitch limits than a retractable model. Commercial installations can also require permits or engineering review. Local rules should be checked before installation.
Use the comparison table to test several common projections. A negative difference means the candidate is too short. A positive difference shows extra planning depth.
This calculator supports early design and product comparison. It does not verify wall anchors, wind loading, drainage, or structural capacity. Final dimensions should follow professional and manufacturer guidance.
Frequently asked questions
What is awning projection?
It is the horizontal distance from the mounting wall to the awning front edge.
Is projection the same as awning length?
No. Sloped length follows the angled fabric or arm, while projection is horizontal.
Which angle should I use?
Use the installed pitch specified by the awning manufacturer or measured on site.
How does solar altitude affect projection?
Lower sun angles generally require more projection to shade the same target height.
Why add a safety margin?
It helps avoid selecting a projection that is barely sufficient after real installation tolerances.
What does the arm-limit warning mean?
The calculated recommendation is larger than the maximum extension entered for the hardware.
Can I use feet and inches?
The calculator supports feet or inches as separate decimal units. Convert mixed measurements first.
Are the seasonal solar presets exact?
No. They are generic planning values. Accurate work needs location-specific solar data.
Does this calculator check structural safety?
No. It does not calculate anchors, wind loads, wall strength, or engineering capacity.