01 UNIT & YIELD WORKSHEET
Film thickness, gauge, basis weight and yield worksheet
Thickness, gauge, basis weight and yield can describe related quantities, but they are not interchangeable measurements. This worksheet starts from the buyer’s values, uses the exact NIST conversion of one mil to 25.4 micrometres, and leaves density and gauge convention blank until the user supplies them.
02 DECISION FRAME
Convert units first; keep measurement and calculation separate
ISO 4591 and ASTM D4321 address average thickness or package-yield decisions, ISO 1183-1 addresses plastic density, and flexible-packaging thickness standards define measurement context. A formula result based on nominal thickness and entered density is theoretical; it is not an actual basis-weight, roll-mass or delivered-yield measurement.
- Normalizing a supplier quote that uses micrometres, millimetres, mils or a declared gauge convention
- Building a planning estimate from identified thickness, density, width and length inputs
- Finding which measurement source or commercial tolerance is still missing from an RFQ
- That “gauge” has one universal numeric convention across every market or supplier
- That nominal polymer density represents a coated, filled, voided, printed or laminated web
- That theoretical area yield or roll mass is a delivery guarantee or acceptance result
03 COMPARISON MAP
Name the input, formula, unit and evidence boundary
The formulas below are transparent planning relationships. Empty inputs stay empty in the worksheet.
Swipe or scroll horizontally to review every evidence column.
| Output | Required buyer inputs | Displayed formula | Do not confuse with |
|---|---|---|---|
| Thickness in millimetres | Thickness in micrometres | mm = µm ÷ 1,000 | A new thickness measurement |
| Thickness in mils | Thickness in micrometres | mil = µm ÷ 25.4 | A supplier-specific gauge convention |
| Gauge under declared convention | Thickness in µm and gauge units per mil | gauge = (µm ÷ 25.4) × entered factor | A universal gauge definition |
| Theoretical basis weight | Thickness in µm and density in g/cm³ | g/m² = µm × g/cm³ | A gravimetric basis-weight result |
| Theoretical area yield | Theoretical basis weight | m²/kg = 1,000 ÷ g/m² | Actual package yield or saleable area |
| Theoretical length or roll mass | Basis weight plus width and, for mass, length | m/kg = m²/kg ÷ width; kg = g/m² × width × length ÷ 1,000 | Delivered net weight, core weight or usable roll length |
03A BROWSER-ONLY WORKSHEET
Convert buyer inputs without inventing a film specification.
Leave unknown fields blank. The worksheet does not send, save or measure anything; it applies the displayed formulas only to the values you enter.
Unit basis: a one-micrometre layer over one square metre has a volume of one cubic centimetre, so thickness in µm multiplied by density in g/cm³ gives a theoretical mass in g/m².
Actual average thickness, density, coatings, inks, adhesives, fillers, voids, moisture, core and roll construction can change the measured mass or delivered yield. Confirm the thickness method, density source, gauge convention, sampling plan and commercial tolerance with the responsible parties. Do not use this worksheet as an acceptance test or quantity guarantee.
04 SELECTION SEQUENCE
Move from a broad comparison to an approvable decision.
Name each input source
Distinguish nominal thickness from measured average thickness, and material density from a measured value for the exact construction.
Keep the formula and units visible
Do not hide gauge conventions or density assumptions. Leave an unknown field blank and ask the responsible supplier, converter or laboratory.
Reconcile against actual delivery
Compare planning estimates with the agreed test, sampling, net-mass, core and usable-length definitions before setting a commercial acceptance rule.
05 RFQ INPUTS
Thickness, basis-weight and yield worksheet checklist
Record the calculation inputs beside the measurement and commercial definitions they cannot replace.
Open the RFQ brief builder ↗- 01
Material, grade, construction, coating or print status and supplier data revision
- 02
Nominal or measured thickness, unit, method, instrument and sampling locations
- 03
Gauge term exactly as used by each party and confirmed gauge units per mil
- 04
Density value, unit, source, specimen identity, method and test condition
- 05
Web width, unit, tolerance, measurement method and usable-edge definition
- 06
Roll length basis, splice treatment, start / end allowance and measurement method
- 07
Gross mass, net material mass, core mass and packaging-mass definitions
- 08
Theoretical basis weight, area yield, length per kilogram and roll-mass formulas used
- 09
Actual roll or lot reconciliation, rounding rule and tolerance owner
- 10
Commercial acceptance, dispute method and record retained with the order
06 EVIDENCE BOUNDARY
The worksheet calculates; it does not measure or guarantee
NIST supports the unit conversion, while ISO and ASTM sources define separate thickness, density and yield contexts. ASTM D4321 provides an actual package-yield test-method context; this worksheet does not perform that measurement. It calculates nominal theoretical area yield from entered thickness and density, uses only entered values and does not reproduce paid procedures. Coatings, fillers, voids, moisture, thickness variation, core and unusable material can make actual delivery differ from a theoretical result.
07 BUYER QUESTIONS
Resolve the assumptions that make quotes diverge.
01Does film gauge always mean the same value?+
No convention is assumed here. Confirm how many gauge units the buyer or supplier assigns to one mil, record that factor, and retain the original thickness unit in the RFQ.
02Is calculated basis weight the same as a measured basis weight?+
No. The worksheet multiplies entered thickness by entered density. An actual construction can differ because of thickness variation, layers, coatings, inks, fillers, voids, moisture and the selected measurement method.
03Can theoretical yield be used to approve a delivered roll?+
Not by itself. Define actual net mass, core, usable width and length, splices, allowances, measurement methods, sampling and commercial tolerances before accepting or disputing delivery.
04Does the worksheet save or submit entered values?+
No. It performs the displayed calculations in the browser. Keep the source values and agreed acceptance record in the buyer’s controlled RFQ or quality system.