Filet Crochet Guide: Open Blocks, Filled Blocks, and Reading the Mesh
Filet crochet builds pictures from just two things — solid blocks and holes. Learn what the mesh blocks mean, how to read a chart row by row, and how to chart your own design.
Filet crochet is a lace technique built from a grid of mesh blocks. A filled block is solid fabric — traditionally three double crochet. An open block is a hole — two chains worked over skipped stitches, capped with a double crochet. Alternate the two across a grid and the filled squares draw a picture against the open background: silhouettes, lettering, borders, whole pictorial panels. Crocheters have charted filet this way for over a century, which is why antique filet charts still work perfectly today.
The chart is a two-color grid — one color means filled, the other means open. That simplicity is the technique's whole charm and its one hard rule: there is no shading. Everything the design says, it says through which squares are solid. One subtlety hides in the math: neighboring blocks share their edge stitch, so each block costs three stitches but the first stitch of a run belongs to the block before it. Ten blocks in a row is thirty-one double crochet, not thirty.
Because a filet chart is literally two states per square, it's the most automatable of all crochet chart types — any image can be thresholded into filled and open blocks, and the legend can count both exactly. Those counts double as a yardage estimate for your thread or yarn.
How to read a filet chart, row by row
Start at the bottom-right
Filet charts are read bottom-up. Row 1 is the bottom row of the grid, read right-to-left. The turning chain at the start of a row counts as the edge stitch of the first block.
Work filled blocks as double crochet
A filled square is solid mesh: double crochet into every stitch or space it covers — three double crochet per block, with the edge stitch shared between neighbors. Solid runs are the easy part; just keep count.
Work open blocks as chains
An open square is a hole: chain 2, skip the two stitches or space below, and double crochet into the next edge stitch. Consistent chain tension is what keeps the holes square instead of sagging.
Turn, and read the next row backward
Row 2 reads left-to-right because the fabric is flipped. Keep a marker on the chart row you're on — losing the reading direction halfway through a motif mirrors half of it.
Count against the chart
At the end of each row, verify: every block on the chart row should correspond to three stitches minus the shared edges. A two-minute count per row beats frogging forty rows of shifted mesh.
Filet instructions are short but dense with abbreviations — dc, ch, sk. The crochet abbreviations decoder expands them in plain English, and the crochet symbols chart covers the drawn-symbol versions you'll meet in older filet patterns.
Beginner mistakes that blur the picture
Forgetting the shared edge stitch
Adjacent blocks share one double crochet, so ten blocks are 31 stitches, not 30. Worked naively, every block adds a phantom stitch and the fabric fans out wider with each row.
A turning chain of the wrong height
The turning chain stands in for the first double crochet of the first block. Chain too few and the edge cinches; chain too many and the edge scallops. For double-crochet filet, chain 3 (plus 2 more if the first block is open).
Loose open blocks
Open blocks are only chains, and loose chains make holes that sag and drift, blurring the motif. Keep chain tension a touch tighter than your double crochet; the holes should be square, not teardrops.
Choosing a shaded source image
Filet keeps two states — filled or open — so gradients and soft detail vanish by design. A photo of a face becomes an abstract blob; a silhouette of the same face becomes a beautiful chart. Pick subjects that survive pixelation to two colors.
Thread finer than the chart
Fine thread shows detail, but a 120-block chart in size 20 thread is a long commitment. Swatch a 10-block square, measure it, and do the finished-size math before choosing materials.
Make your own filet chart
The free filet crochet pattern generator converts any image into a classic two-color mesh chart: upload a silhouette, monogram, or bold graphic, set the grid anywhere from 20 to 120 blocks wide, and download a printable PNG with exact filled-vs-open block counts in the legend. A quality score tells you up front whether your image has enough contrast to survive two-color conversion. For ready-made practice charts, the free filet pattern library is a good place to learn the rhythm before designing your own.
Feed the block counts into the yarn calculator for a thread estimate, and if the idea of pictures-from-grids appeals to you, the mosaic crochet guide covers a neighboring technique that builds geometric designs from a chart worked one color per round.
Common questions
What is the difference between open and filled blocks in filet crochet?
A filled block is solid fabric — typically three double crochet. An open block is a hole — typically two chains worked over skipped stitches, topped with one double crochet. On the chart, filled squares form the motif and open squares form the background. The whole technique is just these two states repeated across a grid.
How many stitches are in a filet crochet block?
Usually three stitches per block, with a catch: adjacent blocks share their edge stitch. A run of four filled blocks is 3 + 3 + 3 + 3 plus one shared edge, so thirteen double crochet, not twelve. Forgetting the shared edge is the classic reason filet pieces gain a stitch per block.
Which way do you read a filet crochet chart?
Bottom up, one grid row per crochet row. Read odd rows right-to-left and even rows left-to-right when working flat, because you're turning the fabric each row. Each square is one mesh block: filled means double crochet, open means chains over the space below.
What yarn or thread is best for filet crochet?
Traditional filet uses size 10–20 cotton thread with a 1.5–2 mm hook for curtains, doilies, and table runners — fine thread shows more detail at the same block count. Worsted yarn and a 5 mm hook turns the same charts into blankets and wall hangings. Match the material to how much detail your chart needs to show.
Why does my filet crochet keep gaining stitches?
Almost always the shared edge stitch. Each block after the first shares one double crochet with its neighbor, so a row of ten blocks is 31 stitches, not 30. Count your double crochet against the chart at the end of every row for the first dozen rows — the habit sticks after that.
Can you make a filet crochet pattern from a photo?
Yes — filet is the easiest technique to automate because the chart has exactly two states. A filet generator thresholds the image into filled and open blocks and counts both. Silhouettes, monograms, and bold line art convert cleanly; shaded photos turn abstract, so pick sources with strong shapes.