Feet, inches
& fractions.

Enter a decimal such as 12.5, a fraction such as 3 1/4, or a measurement with a unit, such as 254 mm. Press Enter or tap equals. You can select and replace an answer to begin a new calculation in its displayed unit. Combined feet-and-inches text and full expressions are not accepted; enter each measurement separately.

Tap Units or the unit name above the display. While entering, this labels your number as inches, feet, millimetres, centimetres or metres. After equals, it converts the same answer. Each new operand returns to inches, just like the app.

For example: enter 2, choose Feet, select ½, tap +, enter 254, choose Millimetres, then =. The result is 40 in. Choose Centimetres to display 101.6 cm.

Choose ¼, ½ or ¾, or open Refine for a slider and all fifteen sixteenths. A fraction replaces the fractional part of the current entry; it does not add to it. Fractions use your selected entry unit, so ½ ft equals 6 in.

Operations run from left to right, like the app: 2 + 3 × 4 gives 20. Percentage divides the current operand by 100. Change sign is in the Units menu.

Like the app, entries are converted to inches before arithmetic. Multiplication and division are numeric operations, not dimensional area or ratio calculations. To scale a measurement, leave the multiplier or divisor in the default inch setting.

Only the inch fraction readout rounds to 1/16. Conversions and further calculations use the underlying value. The decimal readout uses up to ten significant digits. Check your source measurements and cutting allowances independently.

Enter each measurement separately and choose its unit before the next operation. For 2 ft + 6 1/2 in, type 2 ft, press +, type 6 1/2 in and press =. The answer is 30 1/2 in. Combined notation such as 2 ft 6 in is not accepted in a single entry.

The tape reading rounds to the nearest 1/16 inch. A value between sixteenths can therefore have a different decimal readout. Further calculations use the underlying value, not the rounded tape reading.