Leathercraft Math: Hide Areas & Yield, Thickness Conversions, Pattern Layouts, Stitch Counts & Thread Length, Edge Finishing and Pricing per Piece

What you'll build

What you will be able to do

Each lab ends with a concrete result that you build yourself and the checker confirms, cell by cell.

• Convert five fictional hide offers from square feet into dm² and m², compare them on price per dm² and let a formula name the cheapest cut.
• Look up the thickness in mm for each leather weight from a fictional supplier table, add up the layers at each seam, flag stacks that exceed a fictional tool limit and turn a caliper reading back into the nearest weight.
• Take off edge losses and marked flaws from five fictional hides, compute the usable share of each, find the real cost per usable dm² and pool the yield over the whole purchase.
• Estimate how many pattern pieces fit on the usable rectangle of a fictional hide in two orientations, keep the better one with MAX and work out how many hides a batch needs.
• Count the stitches on five fictional seams from their length and stitch spacing, estimate the thread with a fictional factor plus tails and work out the thread and spools for a batch.
• Measure the edges to be finished on a fictional card wallet, estimate the edge coat from a fictional label rate and coats, price the hardware and packing with SUMPRODUCT and add them up per item.
• Split each step of making a fictional card wallet into set-up and per-piece minutes, compare a single piece with a batch of 12 and measure the time saved per piece.
• Build the full cost of four fictional products from materials, minutes, labour and overhead, set wholesale prices at a target margin, derive rounded retail prices and chart cost against both prices.