Hidden Square

Making Hidden Square Blocks

Pros and Cons

(compared to cutting rectangles)


– Accuracy
– Less sewing on the bias

– Extravagant with Fabric
– Slower


Most often used with:

Hidden Corner
Hidden Corner

Birds in Air
Birds in the Air


HC measure

Size of square for Hidden Square:
The length of the triangle’s side
plus ½”.


Sew the squares together:

HC use squares

HC sew squares R

Mark the wrong side of the unit with a pencil line aligning the corners of the squares and the intersection of the seams.

HC sew squares W


Line up the corner of square (a square can be used in the same manner as Covered Corners) or triangle you will add to the corner of the unit:

HC sew tri

Sew a seam one thread’s width from the marked/ironed line. This tiny allowance makes room for the fold of the fabric so that the ‘point’ isn’t cut off the triangle.


FIRST, fold the triangle into position, using the squares to assist alignment. Press.

HC fold tri W align

Trim away the excess fabric to reduce bulk, leaving a ¼” seam. Trim the ‘ears’ (there will be no ‘ears’ if Covered Corners measurements are used).

HC fold tri W trim

HC fold tri R