How we calculate

Every tool’s formula, where it comes from, and where we made a judgement call.

By the Toolkit Cove team · Checked 19 October 2026 · How we calculate

Epoxy resin

Coat: area in sq ft × coverage, default 4 fl oz of mixed resin per sq ft per coat (ArtResin’s figure for its self-levelling coat), × coats. Pour: length × width × depth in cubic inches ÷ 1.8047 (231 cubic inches = 1 US gallon = 128 fl oz; NIST). Round pieces use π × diameter² ÷ 4. Both add the extra you choose (default 10%) and split by the mix ratio by volume. 1 fl oz = 29.5735 mL. The kit suggestion is the smallest common combined size (8, 16, 32, 64, 128, 256 fl oz and up) that covers the total.

Candle wax

Fill weight (oz) = container capacity (fl oz) × 0.86 (GlassNow). Our judgement call: we split the fill weight into wax = fill ÷ (1 + load) and fragrance = fill − wax, so the fragrance stays the chosen percentage of the wax weight without overfilling the container. GlassNow’s own example adds the fragrance on top. From a bag: fragrance = wax weight × load; candles = wax weight ÷ wax per container, rounded down.

Yarn

Yards by project and Craft Yarn Council weight from Lion Brand Yarn’s chart; skeins = yards ÷ yards per skein, rounded up at both ends of the range. Swap: pattern skeins × pattern yards per skein ÷ your yards per skein, rounded up. 1 yd = 0.9144 m.

Fabric yardage

Backing (Missouri Star): top + 4 in per side (you can change it); usable width 40 in for 42–44 in fabric, 52 in for 54 in, 58 in for 60 in, 104 in for 108 in and 114 in for 118 in backing (the 54 and 60 in figures are our assumption: 2 in for selvages). Panels = the fewest that cover one side, each ½ in seam taking 1 in; yardage = panels × the other side ÷ 36, rounded up to ¼ yd. We try both directions and show the smaller. Binding (USU Extension): 2 × (width + length) + 10 in; strips = that ÷ usable width, rounded up; yardage = strips × strip width ÷ 36, rounded up to 1/8 yd. Cut pieces: pieces per row = usable width ÷ piece width, rounded down; rows = pieces ÷ per row, rounded up; yardage = rows × piece height ÷ 36, rounded up to 1/8 yd, trying the pieces both ways round.

Quilt size

Width = mattress width + 2 × drop; length = mattress length + drop + pillow tuck (Missouri Star). Mattress sizes: crib 28 × 52, twin 38 × 75, full 54 × 75, queen 60 × 80, king 76 × 80, California king 72 × 84 in. Batting: the smallest common size at least 2 in larger than the quilt on every side (our minimum; longarm quilters often ask for 4 in). Backing and binding use the fabric formulas above.