ESG Score Calculator

This calculator combines Environmental, Social and Governance scores into a single figure, weighted however you choose. Scores of 75, 60 and 80 weighted 33%, 33% and 34% give a composite of 71.8 out of 100. Composite ESG scores are used to screen holdings, to track a company's own progress, and by employees weighing up an employer; MSCI, Sustainalytics, Refinitiv, ISS and Bloomberg all publish their own.

A worked example

Take a company scoring 75 on environmental measures, 60 on social and 80 on governance. At the default 33/33/34 weighting the composite is 71.8, which falls in the B band. Shift the weighting toward governance and the composite rises, because governance is the strongest of its three scores. That sensitivity is the point: providers weight by industry materiality, so an oil company's environmental score carries more weight in their composite than a software company's does, and the same underlying scores produce different headline numbers.

Where composite scores are used

Sustainable and ESG-aligned assets run into the tens of trillions globally, though industry estimates vary widely with the definition used. The field spans active ESG funds, ESG ETFs and exclusion-based funds that screen out sectors such as tobacco or weapons. Two problems recur. Greenwashing describes claims made without substance behind them. Rating inconsistency describes the same company receiving materially different scores from different providers, which is the subject of the next section.

Why the same company scores differently across providers

The same issuer can score well with one provider and poorly with another, and the disagreement is structural rather than a data error. Providers differ in three ways that this calculator makes visible. They apply different materiality maps, weighting pillars differently by industry; the weights here are the input that models that. They emphasise different underlying data, so the component scores that feed the weighting differ before any weighting is applied. And they treat disclosure gaps differently, some scoring a non-disclosing company as unknown and others as poor. The composite here captures only the first of those three: it takes whatever component scores are entered and applies whatever weights are entered. The variation that arises before the weighting is outside it.

Which inputs matter most

Each component score moves the composite by its own weight divided by 100. At the default weighting that is 0.33 points per point of Environmental score, 0.33 for Social and 0.34 for Governance, so a ten-point improvement in governance adds 3.4 to the composite. The weights work differently, because one cannot move alone: the three must still sum to 100, so a weight change is always a shift between two pillars. Moving one percentage point from Social to Governance moves the composite by the gap between those two scores divided by 100: at 60 and 80 that is 0.20 points. Moving a point from Governance to Environmental moves it by (75 − 80)/100, or −0.05. So the weight lever is governed by the gap between the two pillars being traded, not by either score on its own, and it does nothing at all when the two scores are equal.

What's happening under the hood

The composite is the weighted average of the three scores: each score multiplied by its weight, summed, and divided by 100 because the weights are entered as percentages. The three weights must sum to 100 and the calculator returns an error rather than a score if they do not, so weights of 33, 33 and 33 are rejected rather than quietly rescaled. That also means an exactly equal split is not enterable at whole-number weights; 33/33/34 is the closest available.