Units

Type the unit after the number, the way you would say it. Calculeaf reads that as multiplication by the unit. 12 kN/m is twelve kilonewtons per metre, and that dimension travels through every calculation below. It is not a bare 12 with a label stuck on. That is what stops a sheet adding a length to a force.

Attach a unit

A space between the number and the unit is the usual form, though it is not required. 5kN parses the same as 5 kN. Build compound units with /, *, and ^:

w := 12 kN/m =
p := 20 N/mm^2 =
A := 150 mm^2 =

A unit can also follow a closing parenthesis, as in (w * L / 2) kN. That is rarely what you want. If w and L already carry units, the product already has a dimension, and multiplying by kN again gives you kN squared per metre. Reach for to() instead when the intention was to state the answer in kN.

Pick a unit from the ribbon

Clicking beats typing when you are unsure of the exact token. On the Math tab, the Units group offers quick buttons for m, kg, s, N, Pa, J, W, kN, MPa, and deg. Units ▾ opens the full set by category: Length, Mass, Time, Force, Pressure, Energy, Power, Temp, Velocity, Area, Volume, Angle, Electric, and Freq. Either way the token drops into the math region that has focus. The unit reference lists every token Calculeaf accepts.

When the dimensions do not agree

Calculeaf refuses rather than guesses. Add metres to seconds and the region reports Incompatible units, usually with the two units named, as in Incompatible units (meter → second). Pass a length into a logarithm and you get ln() requires a dimensionless argument. Both point at a real modelling error somewhere upstream. Fix the expression rather than stripping the units to make the message go away.

Pin a display unit

Click the unit on the answer chip and choose a compatible one. This changes how that single region displays and nothing else. The stored value is untouched, and every region that uses the name still sees the same quantity. Right-click the region and choose Reset units to drop the pin and go back to the worksheet default. To put the target unit in the expression itself, where a reader of the printed sheet can see it, use to().

Next, unit systems if you need the whole sheet to read in feet and pounds, or conversion with to() to force one answer into a particular unit.