How we calculate our food waste figure


The methodology outlined below is used to calculate the total tonnes of food wasted in our Irish operations for the full Tesco financial year2020/21. The information provided is in conformance with the Food Loss and Waste Accounting Standard (FLW Standard).[1]


 In line with our financial reporting, the published figures for food waste covers our 2020/21 financial year, which runs from 1st March 2020 to 27th February 2021 inclusive.

Store Location and Type

The scope of this calculation covers food waste arising only from our depots and stores in Ireland. Food waste arising in customer restaurants and staff canteens in our stores and depots are out of scope, as is any food waste arising in operations owned by Tesco, upstream in the supply chain, such as haulage wastage and committed crop wastage.

The calculation only covers our operations. Therefore, waste arising at our suppliers’ sites and from third party counters in Tesco Ireland stores is not included.

Food Waste Definition

The food waste definition used by Tesco is aligned with that of the UK food waste Reduction Roadmap as well as that adopted by Champions 12.3.

Material types: The scope of the calculation includes food waste and associated inedible parts.

Destinations: While multiple destinations fall under the definition of “food waste” for Tesco Ireland, food waste only goes to Anaerobic Digestion. Zero food waste goes to landfill.

Therefore, food donated to charities via the FoodCloud programme is not considered to be food waste.

Packaging waste is excluded.

Food Categories

All food categories sold at Tesco Ireland are included in the scope[2].

During the calculations, all non-food items are removed from our waste data. The following products are out of scope and therefore excluded from the calculations:

  • All products within Baby, Beauty & Toiletries, and Healthcare, Optician & Pharmacy categories except baby food and nutritional fitness food.
  • All products in the Household & Petcare category except food items.
  • All petcare and incense products in the Grocery category.
  • Plants and flowers in the Produce category.
  • Store transfers were also excluded.
  • Some individual products were excluded in other categories where they were clearly not food, for example: books, glassware.

Data Sources

In order to calculate the amount of food wasted each year we record the following data in our stores and depots.

Retail waste: This dataset contains the number of retail units wasted and the total value of such waste per item, split by waste type –

  • DAM waste: products that are damaged in store, whether on the shop floor or in storage. This also includes waste arising from customer returns and from clearance events.
  • OOC waste: Products that exceed the ‘Best before’ or ‘Use by’ date and can no longer be sold
  • Product Write Off waste: Products that are not suitable for sale. For example, the supplier has sent a request to withdraw the product as it is not safe for consumption.
  • Exceptional Events waste: Products that are damaged during an exceptional event. For example, this waste could be caused by a fridge breakdown or flood.

Depot waste: This dataset contains the number of depot units wasted and the total value of such waste per item. Depot waste figures are reported as a mixture of positive and negative totals. Negative figures are losses, i.e. waste. Positive figures are single items that have been retrieved from wasted packs (e.g. individual cartons retrieved from a broken case). The total waste per item is the sum of losses and gains multiplied by minus one, to align these data with other datasets.

The dataset showed that multiple products had a net negative depot waste, indicating that more stock had been retrieved than initially existed. Tesco identified that stock had been removed due to damage, however the damage transaction had not been completed due to a processing failure. Some of this stock was still retrieved. It was not possible to identify the actual damages, therefore products with net negative depot waste are set to zero to avoid underreporting waste.

Product data: This dataset contains the contents weight and the packaged weight per item. Note that where duplicates are found, a conservative estimate is taken and the highest weight is used.

Bakery Weights data: This dataset contains the weight per item for bakery products that do not have a weight assigned in the product weight data. The product specification weight is provided by our bakery team.

Self-scan data: This dataset contains the packaged weight of items as measured in store self-scan tills. This data is used where product data from the source above is not available. Note that where duplicates are found, a conservative estimate is taken and the highest weight is used. Given these data include packaging, these are only used for items where a more suitable weight is not available and where the weight of packaging is not considered to be significant.

Surplus food donations programme: This dataset contains the number of units and value of food donated to charitable food organisations through our partnership with Irish social enterprise FoodCloud. These donations are also recorded as part of the OOC waste detailed above and are subtracted from these to avoid double counting.

Colleague Shop: This dataset contains the number of units and value of food given to colleagues through our Colleague Shop programme. This food is also recorded as part of the OOC waste detailed above and are subtracted from these to avoid double counting.

Other charity data: FoodCloud provides data for donations from our ambient and fresh depots. Donations from depot include oversupply and rejected food owned by suppliers, where the donation is facilitated by Tesco. These are included in the donations figure and in the total surplus figures.


The bullet points below explain how we have calculated our total food waste tonnage for the full year2020/21:

  • Included in the scope of our calculation is any food that has not been sold in our stores because it is past its best before or use by date, has been damaged, withdrawn from the market or de-ranged. The non-food categories mentioned above are removed at this stage.
  • The number of units wasted per item is converted into a weight measured in tonnes by multiplying the number of units wasted by the per unit weight*.
  • We perform a ‘bottom up’ calculation from the waste tonnages for individual products (e.g. Gala Apples), to the commercial food category (e.g. Produce), to our entire Irish operations.
  • Waste tonnages are summed to obtain totals by category and for our entire Irish operations.
  • We used this calculation method for 84% of the waste products (by weight) from our own operations – in our depots and within our stores.
  • The remaining 16% of waste by weight (equivalent to 21% of total units wasted) occurs in products for which a weight is not available (this could include items such as baguettes in our bakery or food in our deli counters) or where the weight provided is not correct.
  • The following steps are taken to select the best estimate for product contents weights:
    1. Product content weights are checked category by category and are marked as requiring adjustment where the content weight is missing or if it is high or low compared to the category average.
    2. If an adjustment is required, packaged weights are selected where available and if appropriate per expert judgement.
    3. For all items with no packaged weight data available, items are checked on a sub-category basis and either the category or sub-category average is used based on expert judgement.
    4. For the Bakery category, primary data collection was necessary to obtain average weights for several sub-groups.
  • To minimise the risk associated with such estimates, categories with the largest number of waste items are prioritised and checked in more detail as these have the greatest impact on the total waste.
  • In addition, within each category, the products with the highest number of wasted units are checked manually one-by-one as these can also have a significant impact on the total waste tonnage.
  • Where charity donations are included in our waste records we subtract the donated tonnage from our food waste figure as these items are donated for human consumption.

* It is assumed that 1 L is equivalent to 1 Kg where product content weights are listed as volumes.

Food waste intensity figures

0.86% of food was wasted in our ROI operations in 2020/21.  In line with the Food surplus and waste measurement and-reporting UK guidelines from 2020/21 our food waste intensity figure represents our food waste as a percentage of food handled. Restated figures are shown below.

Food handled is the sum of food wasted, donated and sales. The figure for food sales is measured using the same method for food wasted: multiplying the number of units handled by the same per unit weight used in the calculation described above.


Find below the restatement of food waste intensity figures from FY 16/17 to FY 20/21. This restatement accounts for the change in definition of food waste intensity as described above.

Financial Year

Total Food Waste


Food Waste per sales

(by weight)

FY 16/17



FY 17/18



FY 18/19



FY 19/20



FY 20/21




[1] More information available here.

[2] United Nations Central Production Classifications 2.1 Divisions 21 – 24