The average number of **menstrual cycles** is **12.6**, based on 8 data points.

The average **number of years a person menstruates** is assumed to be **37.5 years**. The NHS doesn’t explicitly say the number of years a person menstruates, but the data they report suggests a similar value.

## Number of units

##### Single-use products

The average number of **pads per cycle** is **19.1**, based on 6 data points.

The average number of **tampons per cycle** is **20.0**, based on 4 data points.

The **average number of single use items** used in the modelling is **20.0 items per cycle** – this is an average of 10 pads and 10 tampons.

Multiplied by 12.6 cycles per year (see Section 1), this equates to **253 items per year**.

Multiplied by 10 years, this equates to **2,526 items per 10 years**.

Multiplied by 37.5 years of menstruation per lifetime (see Section 1), this equates to **9,472 items per lifetime**.

##### Cup

The average number of **years per menstrual cup** is **7.5**, based on 13 data points.

This equates to **0.13 cups per year**.

Multiplied by 10 years, this equates to **1.3 cups per 10 years**.

Multiplied by 37.5 years of menstruation per lifetime (see Section 1), this equates to **5.0 cups per lifetime**.

##### Reusable pads

The average number of **reusable pads per year** is **2.4**, based on 3 data points.

Multiplied by 10 years, this equates to **24 reusable pads per 10 years**.

Multiplied by 37.5 years of menstruation per lifetime (see Section 1), this equates to **90 reusable pads per lifetime**.

##### Underwear

The average number of period **underwear per year** is **1.9**, based on 5 data points.

Multiplied by 10 years, this equates to **19 underwear per 10 years**.

Multiplied by 37.5 years of menstruation per lifetime (see Section 1), this equates to **69 underwear per lifetime**.

## Price

##### Single-use products

The average unit price per single-use pad is £0.16, based on 164 data points.

The average unit price per tampon is £0.13, based on 88 data points.

The average **unit price per single-use item** used in the modelling is **£0.14**.

Multiplying the number of units from Section 2 by this unit price gives:

**£38.57 per year**(= £0.14 * 253 units per)**£385.71 per 10 years**(= £0.14 * 2,526 units)**£1,446.40 per lifetime**(= £0.14 * 9,472 units)

##### Cup

The average **unit price per cup** is **£25.47**, based on 12 data points.

Multiplying the number of units from Section 2 by this unit price gives:

**£3.40 per year**(= £25.47 * 0.13 units)**£33.96 per 10 years**(= £25.47 * 1.3 units)**£127.35 per lifetime**(= £25.47 * 5.0 units)

##### Reusable pads

The average **unit price per reusable pad** is **£7.46**, based on 19 data points.

Multiplying the number of units from Section 2 by this unit price gives:

**£17.90 per year**(= £7.46 * 2.4 units)**£178.99 per 10 years**(= £7.46 * 24 units)**£671.27 per lifetime**(= £7.46 * 90 units)

##### Underwear

The average **unit price per underwear **is **£17.25**, based on 132 data points.

Multiplying the number of units from Section 2 by this unit price gives:

**£31.93 per year**(= £17.25 * 1.9 units)**£319.26 per 10 years**(= £17.25 * 19 units)**£1,197.24 per lifetime**(= £17.25 * 69 units)

## Waste

All weights exclude packaging.

Reusable products are assumed to be disposed of clean (r.g., underwear are washed to be put in a textiles recycling bin), while disposable products include the menstrual fluid.

##### Single-use products

The weight of each single use product is based on:

- The weight of an unused product
- Plus the maximum weight of menstrual fluid that a product can absorb
- Scaled to 80% under the assumption that not all products are completely maxed out

The average **weight of an unused pad **is **6.7 grams**, based on 5 data points.

The average **weight of a disposed pad **is **13.0 grams**.

The average **weight of an unused tampon** is **2.3 grams**, based on 5 data points.

The average **weight of a disposed tampon** is **9.2 grams**.

The **average weight of disposed single use items** used in the modelling is **11.1 grams**.

Multiplying the number of units from Section 2 by this average weight gives:

**2.8 kg per year**(= 11.1 g * 253 units per)**27.9 kg per 10 years**(= 11.1 g * 2,526 units)**104.8 kg per lifetime**(= 11.1 g * 9,472 units)

##### Cup

The average **weight of a cup** is **13.4 grams**, based on 15 data points.

Multiplying the number of units from Section 2 by this average weight gives:

**0.002 kg per year**(= 13.4 g * 0.13 units)**0.018 kg per 10 years**(= 13.4 g * 1.3 units)**0.067 kg per lifetime**(= 13.4 g * 5.0 units)

##### Reusable pads

The average **weight of a reusable pad** is **35 grams**, based on 5 data points.

Multiplying the number of units from Section 2 by this average weight gives:

**0.08 kg per year**(= 35 g * 2.4 units)**0.84 kg per 10 years**(= 35 g * 24 units)**3.1 kg per lifetime**(= 35 g * 90 units)

##### Underwear

The average **weight of underwear** is **71.2 grams**, based on 10 data points.

Multiplying the number of units from Section 2 by this average weight gives:

**0.13 kg per year**(= 71.2 g * 1.9 units)**1.32 kg per 10 years**(= 71.2 g * 19 units)**4.9 kg per lifetime**(= 71.2 g * 69 units)

## Greenhouse Gases (GHG)

##### Single-use products

The average **GHG emissions per single-use pad** is **0.029 kg CO2e**, based on 11 data points.

The average **GHG emissions per tampon** is **0.021 kg CO2e**, based on 13 data points.

The average **GHG emissions per single use item** used in the modelling is **0.025 kg CO2e per item**.

Multiplying the number of units from Section 2 by this average GHG emissions gives:

**6.4 kg CO2e per year**(= 0.025 kg CO2e * 253 units per)**63.6 kg CO2e per 10 years**(= 0.025 kg CO2e * 2,526 units)**238.6 kg CO2e per lifetime**(= 0.025 kg CO2e * 9,472 units)

##### Cup

The average **GHG emissions per cup** is **0.7 kg CO2e per year of use**, based on 8 data points.

Multiplied by 10 years, this equates to **7.5 kg CO2e per 10 years**.

Multiplied by 37.5 years of menstruation per lifetime (see Section 1), this equates to **28.1 kg CO2e per lifetime**.

##### Reusable pads

The average **GHG emissions per reusable pad** is **1.3 kg CO2e per year of use**, based on 4 data points.

Multiplied by 10 years, this equates to **13.1 kg CO2e per 10 years**.

Multiplied by 37.5 years of menstruation per lifetime (see Section 1), this equates to **49.1 kg CO2e per lifetime**.

##### Underwear

The average **GHG emissions per underwear **is **2.4 kg CO2e per year of use**, based on 5 data points.

Multiplied by 10 years, this equates to **24.1 kg CO2e per 10 years**.

Multiplied by 37.5 years of menstruation per lifetime (see Section 1), this equates to **90.4 kg CO2e per lifetime**.