Spike's Calculators

# Donut Calculate the area and perimeter of a donut shape. This calculator uses feet and or inches for measurements

Donut = a circle with a smaller circle centred inside ### Donut Area and Perimeter

Outer Diameter ft in n
d
Inner Diameter ft in n
d
Decimal Precision

#### Results:

Inner Area ft²
Total Area (Donut + Inner) ft²
###### Area of the Donut
Decimal Square Feet ft²
Square Feet ft² in²
Decimal Square Inches in²
Square Inches in²
Square Metres
###### Outer Perimeter of the Donut
Decimal Feet ft
Feet ft in
Decimal Inches in
Inches in
Metres m
###### Inner Perimeter of the Donut
Decimal Feet ft
Feet ft in
Decimal Inches in
Inches in
Metres m

#### Calculation

1. outer diameter in feet and or inches
2. inner diameter in feet and or inches
3. decimal precision, the number of digits after the decimal point

#### Results

1. the inner area in square feet
2. total area (donut area plus inner area) in square feet and inches
3. the area of the donut in square feet
4. the area in decimal square inches
5. the area in square inches
6. the area in square metres
7. the outer perimeter of the donut in decimal feet
8. the outer perimeter in lineal feet and inches
9. the outer perimeter in decimal inches
10. the outer perimeter in inches
11. the outer perimeter in metres
12. the inner perimeter of the donut in decimal feet
13. the inner perimeter in lineal feet and inches
14. the inner perimeter in decimal inches
15. the inner perimeter in inches
16. the inner perimeter in metres
##### Formula
```A = ta-ti
ta = 𝛑D²
ti = 𝛑d²
𝛑 = 3.14159265
PO = 𝛑D
PI = 𝛑d
PO the outer perimeter of the donut
PI the inner perimeter of the donut
```

##### Conversions
```one square foot ( ft²) = 144 square inches (in²)
one square inch (in²) = 0.00694444444444443 square feet (ft²)
one square foot ( ft²) = 0.09290304 square metres (m²)
square inch (in²) = 0.00064516 square metres (m²)
```