Wing Aspect Ratio Calculator
How long and slender a wing is: AR = b² / S, the span squared over the wing area.
Inputs
Enter the wing span (tip to tip) and the planform area. Use the total area of both wings, including the part inside the fuselage. Drag the handle (or focus it and press ↑/↓) to reorder. Scientific notation such as 1.2e1 is accepted, and any unit converts automatically.
Results
Enter values and press Calculate. Your answer will appear here.
Induced drag vs. aspect ratio
The induced-drag coefficient is CDi = CL² / (π · e · AR), so for a given lift coefficient it falls in inverse proportion to the aspect ratio. This is a straight line of slope −1 on log-log axes. The dot is your wing.
What is being calculated
Reference values
| Aircraft class (approximate) | Span b | Area S | Aspect ratio |
|---|
Typical aspect ratios
| Wing type | Typical AR |
|---|---|
| Delta wing supersonic transport | 1.5 to 2 |
| Fighter aircraft | 2 to 5 |
| General aviation and trainers | 6 to 8 |
| Jet airliners | 7 to 10 |
| Long-range and surveillance aircraft | 10 to 15 |
| Sailplanes (gliders) | 15 to 40 |
High AR gives low induced drag and a high lift-curve slope, but a long wing is heavier, more flexible and harder to roll.
Unit conversions
| Quantity | Conversion |
|---|---|
| Length | 1 m = 100 cm = 1,000 mm · 1 ft = 0.3048 m · 1 in = 0.0254 m |
| Area | 1 m² = 10,000 cm² · 1 ft² = 0.092903 m² · 1 in² = 6.4516×10⁻⁴ m² · 1 dm² = 0.01 m² |
| Force | 1 kN = 1,000 N · 1 lbf = 4.44822 N · 1 kgf = 9.80665 N |
| Wing loading | 1 N/m² = 0.0208854 lbf/ft² · 1 kgf/m² = 9.80665 N/m² |
Formula
- AR: aspect ratio (dimensionless)
- b: wing span, tip to tip (m)
- S: wing planform area (m²)
- c̄ = S / b: mean chord, so AR = b / c̄
Example: A wing with span b = 11 m and area S = 16.2 m² has AR = 11² ÷ 16.2 = 121 ÷ 16.2 ≈ 7.47. The mean chord is 16.2 ÷ 11 ≈ 1.47 m.
Rearranged: b = √(AR · S) and S = b² / AR. For a straight-tapered wing with taper ratio λ = tip chord ÷ root chord, the root chord is c_r = 2S / (b · (1 + λ)) and the tip chord is λ · c_r. Advanced mode also estimates the induced-drag coefficient CDi = CL² / (π · e · AR) and the finite-wing lift-curve slope a = 2π · e · AR / (e · AR + 2) per radian, where e is the Oswald efficiency factor (1 is the ideal elliptical lift distribution; real wings are usually 0.7 to 0.9). These are low-speed, straight-wing estimates and become less accurate for very low aspect ratio, strong sweep or compressible flow. Wing loading is the weight divided by S.
References
- Wikipedia, Aspect ratio (aeronautics): definition and effect on performance
- NASA Glenn, Wing Geometry Definitions: span, area, chord and aspect ratio
- Wikipedia, Lift-induced drag: CDi = CL² / (π · e · AR)
- Wikipedia, Oswald efficiency number: the factor e
How to Use This Tool
- Pick a preset, or enter the wing span b and the wing area S with their units.
- In Advanced, you can instead solve for the span or the area from a known aspect ratio.
- In Advanced, add a taper ratio, lift coefficient, Oswald efficiency or weight for chords, induced drag and wing loading.
- Click Calculate.
- Read AR in the highlighted result, then check the table and the chart.
What This Tool Offers
- Basic and Advanced modes on one calculation engine
- Span from mm to m and ft, area from mm² to m² and ft², with automatic conversion
- Aspect ratio and mean chord, with a comparison to typical aircraft
- Solve for span or area, root and tip chord, induced drag, lift-curve slope and wing loading (Advanced)
- Induced-drag chart and a labelled wing-planform diagram
- Reorderable inputs, presets and a mobile-friendly layout
Variables
| Symbol | Quantity | Unit |
|---|---|---|
| AR | Aspect ratio | |
| b | Wingspan | m |
| S | Wing area | m2 |
What it means
Aspect ratio is a geometric parameter that significantly influences induced drag. High AR wings (e.g., gliders) have lower induced drag but higher structural weight. It is defined as the square of the span divided by the area. For a rectangular wing, AR = span/chord. The aspect ratio appears in the induced drag equation: C_Di = C_L²/(π e AR). Increasing AR improves aerodynamic efficiency, which is why high‑altitude long‑endurance aircraft have large spans. However, high AR can cause structural issues and require more complex wing designs. Understanding AR is essential for wing optimisation and trade‑off studies.
Worked example
Wing Aspect Ratio – Two Examples
Real‑World| Parameter | Value |
|---|---|
| b | 20 m |
| S | 30 m² |
| Parameter | Value |
|---|---|
| b | 12 m |
| S | 25 m² |
Common mistakes
- Aspect ratio AR: AR = b² / S – dimensionless.
- Wingspan b: In metres.
- Wing area S: In m².
- High AR: Indicates slender wing (e.g., gliders) – reduces induced drag.
- Geometric vs. effective: Effective AR may be reduced by winglets or endplates – use geometric for standard.
Applications
Wing aspect ratio, AR = b²/S, is the ratio of wingspan squared to wing area. High aspect ratio wings are long and slender, offering lower induced drag, while low aspect ratio wings are stubby and provide higher structural strength and roll rates. This parameter is a primary driver of aerodynamic efficiency and structural design. Engineers use AR to optimise wings for specific missions: gliders have high AR for endurance, while fighters have low AR for manoeuvrability. Aspect ratio also affects spanwise lift distribution, wingtip vortices, and wake turbulence. By selecting the appropriate AR, aerospace engineers balance aerodynamic performance, structural weight, and manufacturability to meet design requirements.
- Wing planform design for desired lift‑to‑drag ratio
- Trade‑off between induced drag and structural weight
- Design of gliders, UAVs, and high‑endurance aircraft
- Fighter aircraft wing design for agility
- Wake turbulence and airport spacing regulations
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