Methodology & Sources

The US ring size scale is linear in inner circumference: US size = (circumference mm − 36.5) ÷ 2.55, each full size being 2.55 mm of circumference (0.8128 mm of diameter). This matches the ISO 8653 reference system, under which the continental/European size is the inner circumference in millimetres (hence US 7 ≈ EU 54). Quarter sizes are computed from the same formula and rounded to the nearest 0.25. UK/Australian letter sizes and Japanese numbered sizes are mapped from the standard published US↔UK↔JP conversion charts used by jewellery suppliers (e.g. Rio Grande’s ring-size chart); because those scales are not perfectly linear against the US one, UK/JP values are matched to the nearest half-size row. Inside diameter converts via C = π × d. Measurements outside US 3–13 are clamped and flagged.

Binding: length = 2 × (width + length) + corner/join allowance (default 10″, the standard quilter’s slack for four mitered corners plus the diagonal join). Strips = binding length ÷ usable strip length (40″ from a 42″ width-of-fabric, allowing for selvage). Fabric = strips × strip width, converted to yards and rounded up to the nearest ⅛ yard — the standard cutting increment.

Yardage: a packing calculation — pieces per row = floor(bolt ÷ piece width), rows = ceil(quantity ÷ pieces per row), length = rows × piece height. Both orientations are tried for non-directional fabric and the shorter kept; directional prints lock the orientation. Shrinkage inflates piece dimensions by (1 + shrink%) before packing.

Backing and batting: backing = quilt top + 2 × the extra per side (default 4″, a common longarm request) in each direction. Full-width panels are seamed, and each seam takes the seam allowance (default ½″) from both panels, so n panels of usable width u cover n·u − (n − 1)·2s and the panel count is ⌈(backing − 2s) ÷ (u − 2s)⌉. Vertical seams cut each panel to the backing length; horizontal seams cut each panel to the backing width. Both are computed and the shorter total is kept, with vertical winning ties. Directional prints stay vertical. Batting is sized the same as the backing. Usable widths default to 42″ for 44/45″ cotton, 58″ for 60″ fabric and 106″ for 108″ wide backing, and any of them can be overridden.

Half-square triangles: the 2-at-a-time rule is the classic finished + ⅞″ — ¼″ seams on each side plus the bias-diagonal loss. The 8-at-a-time (“magic 8”) method follows the published chart 2 × finished + 1¾″ (two 6¾″ squares yield eight 2½″ HSTs). The 4-at-a-time method follows the geometry of the diagonal cuts: √2 × (finished + 1)″, rounded up to the nearest ⅛″. All methods assume trimming to the exact unfinished size (finished + ½″) with a square ruler.

Working densities (grams per millilitre): soy 0.86, paraffin 0.90, coconut blend 0.92, beeswax 0.96 — standard supplier values; blends vary by a few percent, so weighing a water-filled vessel remains the ground truth. The load convention used throughout the candle industry, and here: fragrance percentage is a percentage of wax weight, not of the finished pour — 10% load in 100 g of wax is 10 g of oil and a 110 g candle. The fill volume holds the whole pour, oil included: pour = fill volume × wax density, wax = pour ÷ (1 + load), oil = wax × load. Weighing the blend at the wax’s density is the usual supplier shortcut; most fragrance oils are slightly denser than wax, so the real blend lands up to about 1% under the fill line rather than over it. Wick suggestions are qualitative starting ranges by vessel diameter (single wick under ~65 mm, medium 65–80 mm, consider double-wicking above 80 mm); wick choice depends on wax, fragrance and dye and always requires a burn test.

Volumes are textbook geometry: box = L × W × H, cylinder = πr²h, sphere = 4/3·πr³, hemisphere = 2/3·πr³, in centimetres giving cm³ = ml. A default 10% mixing-loss allowance covers cups and sticks (adjustable). Mixed-resin density defaults to an approximate 1.15 g/ml, so mass output is a planning estimate; use the product’s technical-data density for an exact separate calculation. The A/B split honours the selected weight or volume basis but deliberately does not convert between them, because that requires product-specific component densities.

Table top / coating mode: volume per coat = area × coat thickness, with area = length × width or π × r² for a round top. Coats and the mixing-loss allowance multiply that volume before the A/B split. Gallons use the exact US definition, 1 US gallon = 231 in³ = 3,785.411784 ml (128 fl oz), and 1 in³ = 16.387064 ml. The figure is the level top surface only; edge run-off, absorption into porous wood and seal coats are left to the allowance or a separate coat.

These are empirical estimates, not standards — the honest part of the site. Stockinette yards per square inch by yarn weight: lace 0.50 (open fabric), fingering 0.85, sport 0.75, DK 0.70, worsted/aran 0.65, bulky 0.55, super bulky 0.45 — chosen as transparent planning coefficients for typical projects of each weight, not measured standards. Stitch factors: stockinette ×1.0, garter and seed ×1.1, cables ×1.2, lace ×0.85. Crochet consumes about 25% more yarn than knitting at the same gauge, so the crochet table (worsted 0.70 yd/in² etc.) runs higher, with openwork ×0.85 and dense stitches ×1.15. An entered stitch gauge adjusts the estimate by (your gauge ÷ reference gauge), a simple sensitivity model that does not capture row gauge or construction. Weigh or unravel a washed swatch for anything where running short matters.

Gauge is a plain ratio: stitches per inch = stitches counted ÷ inches measured, rows per inch the same way. Patterns print gauge per 4 inches (10 cm), so the pattern figure you enter is divided by 4 before it is compared with your swatch. A swatch within 0.12 sts/in of the pattern (about half a stitch over 4 inches) counts as a match; tighter means one needle or hook size up, looser one size down, stepping through the standard metric sizes (2–4 mm in 0.25 mm steps, 4–7 mm in 0.5 mm steps, then 8, 9, 10, 11.5, 12.75, 15 and 19 mm) rather than adding a fixed millimetre amount.

Cast-on = target width × stitches per inch, rounded to the nearest multiple of the pattern repeat (never below one repeat). A crochet starting chain adds the turning chain for the first-row stitch — sc +1, hdc +2, dc +3, tr +4 — after that rounding, because the turning chain is not part of the repeat.

Shaping spreads the stitch change across the rows: each shaping row is placed at its ideal fractional position and rounded, so uneven spacing alternates the two nearest intervals instead of bunching at one end. Even placement uses “(k N, k2tog) × M”, where each repeat consumes N + 2 stitches, and the m1 equivalent, which always leaves a stitch after the last m1. Each-end placement pairs the shaping — one stitch at each edge on the same row (k1, ssk … k2tog, k1 or k1, m1 … m1, k1) — with a single edge stitch on a final row when the total is odd. Plans that would need more k2tog decreases than a row can hold, or an m1 without a strand to lift, are refused rather than printed.

Saponification values (grams of lye per gram of oil) follow the standard published SAP chart used by Bramble Berry / Soap Queen and reproduced in most soap-making references — e.g. olive 0.134 NaOH / 0.190 KOH, coconut 76° 0.190 / 0.266, palm 0.141 / 0.199, shea 0.128 / 0.179. Lye = Σ(oil × SAP) × (1 − superfat). KOH is adjusted for the typical ~90% purity of flake potash (÷ 0.90); NaOH is treated as pure. SAP values vary slightly with oil provenance — production soapmakers verify with their supplier’s certificate. Water: either a water:lye ratio (default 2:1) or a percentage of oil weight (default 33%).

American Wire Gauge (Brown & Sharpe) is defined exactly: d(mm) = 0.127 × 92^((36 − AWG)/39), with AWG 36 = 0.127 mm and AWG 0000 = 11.684 mm as the defining anchors. The reference table is computed from this formula, so it cannot be wrong by transcription. Typical-use notes for jewellery gauges reflect standard bench practice (20–21g ear wires, 16–18g jump rings, 24–28g weaving wire); standard pierced earring posts run 20–21 gauge.

Fabric count is threads per inch, or blocks per inch for Aida. Stitches per inch = count ÷ threads covered by each stitch: 1 for Aida, usually 2 for evenweave and linen, so 28-count over two equals 14-count Aida. Finished size = stitches ÷ stitches per inch, for width and height separately, and fabric = finished size + 2 × the margin per side (default 3″). Cut sizes round up to the next ¼″, or whole centimetre in metric, so the piece is never short. Counts labelled per centimetre convert at 2.54 cm per inch.

Floss is an estimate. One skein of DMC Mouliné Spécial six-strand cotton is 8 m, so it holds 48 m of single strand. A full cross on a stitch of side s = 1 ÷ stitches per inch uses two front diagonals and two vertical passes on the back, (2√2 + 2)·s of working thread, plus a 75% allowance for tails, the needle end and travel. Strand length per cross = that × strands in the needle, and skeins = stitches × strand length ÷ 48 m, rounded up. On 14-count with two strands that is about 1,565 full crosses per skein, the cautious end of the commonly quoted 1,500–1,800. Backstitch, knots, fractional stitches and confetti-heavy colours are not modelled.

The Anchor↔DMC conversion chart (608 pairs) is sourced from the published CyberStitchers floss conversion chart (cyberstitchers.com, retrieved 25 July 2026); color names and hex values are DMC’s. Conversion charts are visual matches and compilers disagree on borderline shades — treat pairs as close equivalents. The DMC color chart covers the most-used solid colors with names as printed on the DMC shade card, cross-checked against two further independent published charts; corrections applied from that check include 816 Garnet, 938 Coffee Brown — ultra dark, 3765/3766 Peacock Blue, 3777/3778/3779 Terra Cotta, 3781/3782 Mocha Brown, 327 Violet — dark, 720 Orange Spice — dark, 352 Coral — light, 758 Terra Cotta — very light and 3706 Melon — medium. A phantom entry for code 358 was removed: 358 is not a current DMC color (it appears in no complete chart, including the CyberStitchers conversion data) and the name it carried belongs to 3778. Code 3771 is left as-is because the independent sources disagree on it. Hex values are screen approximations of dyed cotton — independent published charts disagree with each other by a mean RGB distance of ~35, so there is no machine-readable ground truth; use them for palette planning, never for buying decisions.

Anything you buy rounds up: skeins, strips, yards (to the ⅛), squares of fabric. Anything you cut rounds up to the craft’s increment (⅛″ for quilting, ¼″ or a whole centimetre for cross stitch fabric) so units trim down, never short. Lye rounds down if forced — a slight superfat is safe, excess lye is not. Gauge and measurement results are shown to two decimals and never rounded into the advice.