# How do I estimate the emissions from the office paper we buy?

Canonical: https://senseible.earth/answers/office-paper-emissions-per-ream

Convert reams to weight, then apply a paper factor. A ream of 500 A4 sheets at 80 gsm weighs about 2.5 kg. Multiply total kilograms by a factor for virgin or recycled paper from a published table. It is Scope 3 Category 1 and usually small.

## The weight

One A4 sheet is 0.0624 square metres. At 80 gsm that is about 5 g, so 500 sheets weigh about 2.5 kg.

## The factor

Use a paper factor per tonne from a published set such as the UK government conversion factors, and pick recycled where your invoice says so.

## A year of paper

- 400 reams x 2.5 kg = 1,000 kg of paper
- 1 tonne x the paper factor from your chosen table

## What Senseible does here

Senseible reads quantities, dates and units from your bills and invoices and shows the factor and source used on every line.

- [Filling Scope 3 gaps](https://senseible.earth/answers/how-to-fill-gaps-in-scope-3-data)
- [Purchase order or invoice](https://senseible.earth/answers/purchase-order-or-invoice-for-scope-3)

Sources: [GHG Protocol Corporate Value Chain (Scope 3) Standard](https://ghgprotocol.org/corporate-value-chain-scope-3-standard), [UK Government GHG conversion factors for company reporting](https://www.gov.uk/government/collections/government-conversion-factors-for-company-reporting)

Last reviewed 2026-10-22.