Methodology
How PrintReference Lab calculators work, and the principles that govern every result.
Deterministic Results
Every calculation is performed client-side using the same formula. Identical inputs always produce identical outputs. There is no server-side processing, randomization, or session-dependent state.
Transparent Formulas
All formulas are documented and visible. Weight is calculated as: Area (m²) × Grammage (g/m²) × Sheet Count × Quantity. No hidden adjustments, correction factors, or proprietary modifications are applied.
Standards-Based Dimensions
Paper sizes use ISO 216 (A-series) and ANSI (Letter, Tabloid) standard dimensions. Custom sizes are planned for a future release. Dimensions are stored in millimeters and converted to square meters for calculation.
Precision & Rounding
Per-sheet weight is displayed to 2 decimal places. Per-unit and total weight to 3 decimal places. No intermediate rounding is applied—only the final displayed value is rounded using standard IEEE 754 rounding.
Unit Conventions
Grammage is accepted in g/m² (GSM) as the primary unit. Output weights are in grams (per sheet) and kilograms (per unit and total). Conversions to imperial units use standardized factors.
No Hidden Defaults
GSM and sheet count fields are intentionally left empty by default to prevent accidental calculations with wrong assumptions. Only paper size (A4) and quantity (1) are pre-filled as the most common starting point.