Count what each operation uses and makes
A normal working sc, hdc, dc, tr or slst uses one available base position and produces one new unit in this tool. An inc uses one base and produces two single-crochet units. A dec consumes two bases and produces one unit. The three-stitch variants and double-crochet variants follow their definitions in the symbol key. The checker totals both sides independently rather than guessing a net change from the number of drawn symbols.
For example, a row of six inc symbols consumes six base units and produces twelve. A following sequence of (sc, inc)*6 consumes twelve and produces eighteen. A row of six dec symbols would consume twelve but produce only six. These are accounting statements, not instructions for where every hook insertion belongs.
Start from available foundation positions
Enter the foundation positions that are actually available to the first working row. A chain used only for turning should not be included as an available position by accident. When planning an adjustable-ring start, the first round does not have a fixed number of prior stitches; the checker labels that first input count as unchecked and starts comparing subsequent rounds normally.
If a row consumes fewer units than are available, some bases are unaccounted for. Add explicit skip marks when that is your intention or correct the stitch sequence. If it consumes too many, the row asks for positions the model does not supply. An optional expected-output value provides a separate check against your planned total.
Treat a pass as a narrow result
Equal totals can hide different constructions. A shell, a chain space and several stitches in one shared attachment can require information that a linear count does not contain. This editor supports a bounded symbol set and declares its assumptions rather than claiming to reconstruct those relationships.
Use the count ledger to catch arithmetic mistakes early, then read the chart as a crocheter. Check stitch height, where the row begins and ends, which loops or spaces are used, whether the fabric should lie flat and whether the result matches your swatch. A visually tidy chart is still an untested plan until that construction has been checked.