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# PED | A-Level Economics Notes
- URL: https://www.a-level-economics-tutor.com/ped-a-level-economics-notes/
- Published: 2026-02-12T15:37:49.000Z
- Updated: 2026-06-04T12:22:08.000Z
- Author: Jaisul Naik
- Tags: Y12 Microeconomics Notes

These revision notes cover everything you need to know about **PED** for A-Level Economics. They're designed for students studying AQA A-Level Economics, Edexcel A-Level Economics, and Edexcel International A-Level Economics. Written by Jaisul Naik, UCL Economics graduate and A-Level Economics tutor since 2017.

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### What is the formula for PED?

% change in demand/ % change in price

### What is the definition of PED?

PED is the responsiveness of demand to a change in price.

### What does it mean if PED = 0?

If PED = 0, demand is perfectly inelastic.

This means that, even if the price changes, demand does not change at all.

### What does it mean if PED is between 0 to -1?

If PED is between 0 to -1, demand is relatively inelastic.

### What does it mean if PED is -1?

If PED is -1, demand is unit elastic.

### What does it mean if PED is less than -1?

If PED is less than -1, demand is relatively elastic.

### What does it mean if PED is -ထ?

If PED is ထ, PED is perfectly elastic.

### What are the factors that affect PED?

SANDPIT

- availability of substitutes
- addictiveness
- necessity
- durability
- the price of the good as a proportion of your income
- time

### What is the relevance of PED in terms of a firm's total revenue?

Firms that sell a good or service that is price inelastic in demand can raise prices and their total revenue will increase.

Firms that sell a good or service that price elastic in demand can raise prices but their total revenue will decrease.

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### Summary questions

1. What is the formula for PED?
2. What is the definition of PED?
3. What does it mean if PED = 0?
4. What does it mean if PED is between 0 to -1?
5. What does it mean if PED is -1?
6. What does it mean if PED is less than -1?
7. What does it mean if PED is -ထ?
8. What are the factors that affect PED?
9. What is the relevance of PED in terms of a firm's total revenue?

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