Explore guide
How many granny squares do you need?
Turn a blocked, joined square measurement into rows, columns, and a separate spare count.
Related lessons and tools
Start with the joined repeat
For a 120 × 180 cm motif area and a 12 × 12 cm blocked, joined repeat, plan 10 columns × 15 rows = 150 squares. A 5% spare allowance means making 158 squares. The eight spares do not enlarge the blanket.
Gather these measurements
Measure a sample after the finishing method you intend to use. Join several squares with the actual seam or join-as-you-go method. Measure the distance between corresponding points in adjacent repeats; a loose square alone does not tell you the finished spacing. Record width and height separately.
Decide whether 120 × 180 cm means the motif area or the entire finished blanket. Subtract the planned border from the finished target before entering the motif area.
Work the example
- Divide target width by repeat width: 120 ÷ 12 = 10 columns.
- Divide target height by repeat height: 180 ÷ 12 = 15 rows.
- Multiply the axes: 10 × 15 = 150 squares in the layout.
- Round spare squares upward: 150 × 5% = 7.5, so keep eight spares.
Use the planner below to change the dimensions. Its cover option rounds each axis upward. With 125 cm of target width, eleven 12 cm repeats give 132 cm. It does not crop or redesign a granny square. Choose ten repeats, adjust the border, or make another sample if that excess is unsuitable.
Check before repeating
This arithmetic assumes a rectangular grid of consistent repeats. Hexagons, mixed sizes, irregular joins, and stretching require a measured layout. Yarn quantities and time need their own samples. Divide the layout into color groups before budgeting each yarn.
The figures are original teaching diagrams; the calculation reuses the motif planner's whole-repeat method. Read the joining guide and tool method linked below. For a measurement or calculation correction, use corrections.
Sources for sampling and terminology
Motif layout planner
Turn a measured, joined motif repeat into rows, columns, and a make count for a rectangular project.
Before you use this tool
Join and finish several sample motifs before measuring the repeat pitch between matching points. Enter the motif field after subtracting borders.
Cover rounds up each axis; complete-only rounds down. Extra motifs are spares outside the layout.
Extra outer-edge allowance is added twice to each target dimension. Internal joins belong in the measured motif pitch.
Method and limits
Formula and assumptions
Required field = target width/height + twice the outer-edge allowance. Divide each axis by the finished joined motif pitch, swapping axes when rotated. Cover rounds up; complete-only rounds down. Multiply rows by columns, then add the rounded-up spare percentage. This model covers aligned rectangular layouts.
Worked example
Example: a 10 × 10 cm joined repeat covering 95 × 135 cm needs 10 columns × 14 rows = 140 motifs; 5% allowance means making 147.
Limits and rounding
Results are planning estimates from the values entered. Displayed decimals are rounded for craft use; whole materials and repeats round up where the method says so. Confirm gauge, material behavior, construction, and finished measurements before committing supplies.