Tart Tin Pastry Calculator

Pastry is rolled as one flat sheet that has to reach across the base, climb both walls and leave an overhang for draping and trimming — so the sheet you roll is always larger than the tin itself. This calculator sizes that rolled sheet as the tin dimension plus twice the depth (for the two walls) plus an overhang each side (default 3.5cm, calibrated to published pastry charts). It then converts the rolled-sheet area to weight using a factor of 0.316g per cm² at a standard 3mm rolling thickness — that comes from rolled dough having a density of about 1.05g per cm³, so a 3mm (0.3cm) sheet weighs 1.05 × 0.3 ≈ 0.316g for every square centimetre.

For a round tin the rolled circle has diameter = tin diameter + 2 × depth + 2 × overhang, and its area is pi × radius². For a square tin the rolled square has side = width + 2 × depth + 2 × overhang. The weight is then split into flour, butter and water (or egg yolk and sugar) by pastry type: shortcrust uses half-fat-to-flour (2:1 flour:fat), pâte sucrée uses the classic 2:1:0.8 flour:butter:sugar (butter ≈ ½ flour, sugar ≈ 0.4 × flour, bound with egg yolk), and pâte brisée is a richer shortcrust. As a sense-check, a 23cm round tin, 3cm deep, works out at roughly 320g of dough (about 215g flour and 107g butter), in line with published charts that give 300-315g of shortcrust to line a 23cm case. The headline "tin surface area" figure reports the actual base + sides area of the tin for reference (pi × r² + pi × diameter × depth for round tins).