Granny Square Hat Layout Planner

Granny Square Hat Layout Planner

Enter the wearer’s head, washed square and joined-pair measurements. The planner compares four, five and six side panels, matches the crown shape and calculates any missing depth.













The five-panel layout is workableIts predicted ring is close to the target and the fabric has usable stretch reserve.
Selected construction5 squares + pentagon6 motifs total
Predicted side ring21.00 in4.5% actual negative ease
Square decisionKeep 4.25 in squareRequired width 4.27 in
4 side squares16.80 in ringNeeds 5.33 in squares
5 side squares21.00 in ringNeeds 4.27 in squares
6 side squares25.20 in ringNeeds 3.57 in squares

Make five matching side squares and one granny pentagon whose five finished edges match the square edge. Join the five side seams, attach one crown edge to each square, try on, then add four band rounds before the brim.

Target hat circumference
21.12 in
Join effect per seam
−0.05 in
Closing seams included
5 seams
Required selected-square width
4.27 in
Current-to-required difference
+0.02 in needed
Measured growth of one square round
0.70 in
Comfortable fabric stretch
20.0%
Residual growth after recovery
2.5%
Stretch reserve after actual ease
15.5 points
Missing shell depth
0.90 in
Band plan
4 rounds / 0.89 in
Predicted pre-brim depth
8.49 in

Construction instruction: Make 5 side squares at the accepted washed width. Make one granny pentagon with five equal edges matching one square edge. Use the measured join for all 5 side seams and all crown edges. Add 4 even band rounds after the wearer checkpoint, then begin the brim.

Physical checkpoint wins: the calculation predicts the ring from the samples, but the assembled crown changes how the shell settles over the head. Try on the complete shell before adding band depth or brim rounds.