Calculadora de Colcha de Retalhos (Quilt)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
blocos = ceil(L/b) × ceil(A/b); tecido/bloco = b² × 1.15
About this calculator
This calculator helps you plan the making of a quilt, also known as a patchwork blanket. It calculates how many fabric blocks are needed to assemble the quilt, considering the desired dimensions (width and height) and the size of each square block. Additionally, it estimates the fabric quantity required per block, including a 15% margin for waste and seams, ensuring you buy enough material for the project.
The calculation works in two steps. First, the number of blocks in each direction is determined: divide the total quilt width by the block size and round up, same for the height. Multiplying these values gives the total number of blocks. Second, the fabric area per block is calculated: the block side squared, multiplied by 1.15 (safety factor). The result is given in square units (e.g., cm² or inches²), and you can adjust according to the unit used.
Use this tool when starting a quilt project, whether for a bed, throw, or decoration. It is useful for correctly sizing the number of blocks and fabric, avoiding overbuying or shortages. For example, if you want a quilt 200 cm by 150 cm with 20 cm blocks, the calculator shows how many blocks are needed and the total fabric. Remember that the final size may vary with seam allowances; consider adding borders if you want a finished edge.
Important caveats: the calculation assumes square blocks and does not account for losses due to cutting patterns or diagonal seams. Always buy extra fabric (beyond the 15%) if the fabric has a directional print or if you are a beginner. Ensure units are consistent (all in cm or all in inches). This calculator does not replace detailed layout planning; for complex designs, consult a quilting tutorial.
Frequently asked questions
Do I need to buy extra fabric beyond the 15%?
Yes, it is recommended to buy 10% to 20% extra on top of the 15% margin, especially if you are a beginner or if the fabric has a pattern that requires matching.
What if I want rectangular blocks instead of square?
This calculator only considers square blocks. For rectangular blocks, you will need to manually calculate the number of blocks in each direction and the area of each block.
Does the calculator account for seam allowances?
Not directly. The 15% margin helps compensate for losses, but the finished block size will be smaller than the cut size. Consider adding a 1.5 cm seam allowance per side when cutting.
Can I mix units (cm and inches)?
No, all measurements must be in the same unit (centimeters or inches) for correct calculation. The calculator does not automatically convert.
What if the number of blocks is not an integer?
The calculator rounds up automatically. You can adjust the block size or quilt dimensions to get a whole number if you prefer.