How do I calculate the carbon footprint of a plastic lunch box?
Weigh each box and lid, multiply the PP or other resin by the supplier's figure, and add seals and any steel containers inside. Add moulding and assembly energy, then divide the plant's energy by boxes made.
Material
- PP or other food-grade resin.
- Silicone seals and clips.
- Steel inner containers in some models.
Process
- Injection moulding.
- Printing or in-mould labelling.
- Assembly and packing.
Per box
Report per box by capacity and weight.
Worked example: plant energy per box (one month)
- Electricity: 50,000 kWh x 0.710 = 35,500 kg CO2
- Boxes made: 200,000
- Plant total: 35,500 / 200,000 = 0.177 kg CO2 per box
- Add resin and any steel parts for the full figure
Inputs are illustrative; use your own bills and production records.
What Senseible does here
Senseible reads the plant's electricity bills (CEA grid factor 0.710 kg CO2 per kWh, CO2 Baseline Database version 21.0) and fuel invoices (IPCC 2006 defaults) into a fingerprinted Scope 1 and 2 record, the plant-level input to a per-unit figure. Bought-in materials go to the supplier evidence trail; product reports are self-declared drafts.
- Product carbon footprint calculator
- Injection moulding footprint
- Thermoformed container footprint
- Chemical industry
Sources: GHG Protocol Product Standard, ISO 14067:2018, Carbon footprint of products (iso.org), IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults), CEA CO2 Baseline Database, version 21.0
Last reviewed 2026-10-21.