Perfectly Elastic Demand

Readers Question: What is the elasticity, if demand is perfectly elastic?

Diagram of Elastic Demand

If demand is perfectly elastic, it means that at a certain price demand is infinite (A good with a very high elasticity of demand). In other words if a firm increased price by 1%, it would see all its demand evaporate.

If demand is perfectly elastic, then demand will be horizontal.

Diagram of Perfect Competition

In a perfectly competitive market it is assumed a firm would have a perfectly elastic demand. This is because if they increased the price, the consumers with perfect information would switch to other firms who offer the identical product.

In perfect competition, we say a firm is a price taker. This means it’s demand curve is perfectly elastic, it has to accept the market price.

Examples of Perfectly Elastic Demand

Foreign currency exchange. If you are buying foreign currency, it is likely to exhibit the features of perfect competition. A buyer could choose from many different sellers. The product (e.g. dollars) is identical. Perfect information about cheapest would be easy to find.
Therefore, if one firm increased the price of dollars, above market equilibrium – no one would buy from that firm. They would buy from cheaper alternatives.

Similarly if you are buying potatoes from Covent garden, it is easy to check prices. Therefore, if a farmer increases price above the equilibrium demand will fall significantly, meaning demand is very elastic.

12 Responses to Perfectly Elastic Demand

  1. sisi May 21, 2009 at 4:01 pm #

    very helpful! thanks!

  2. janine rosalijos July 21, 2009 at 10:36 am #

    thanks! very helpful…..

  3. janine rosalijos July 21, 2009 at 10:37 am #


  4. NTHABI July 30, 2009 at 10:34 am #

    perfect answers thax

  5. NTHABI July 30, 2009 at 10:35 am #

    very much thnx i was kinda confused nd u helpd a lot,keep it up.

  6. arvejhun August 2, 2010 at 12:27 pm #

    it’s hard to know all of these because it can help you<<?

  7. Chipreader September 29, 2010 at 7:21 pm #

    So — good definition, however WHAT IS A PERFECTLY ELASTIC PRODUCT — I can get the concept of perfectly inelastic (ie, insulin), but what product closely resembles perfectly elastic?

  8. nadir ali November 1, 2010 at 7:56 am #

    i agree but my question is this that why the line is straight for price if there is a slight diffrance in price that should also be shown?

    thanks if i am answered

  9. Chris March 7, 2011 at 2:27 pm #

    why on a straight line demand curve where Qd is 0, that we say the Ed is perfectly elastic?

  10. cho October 10, 2011 at 2:22 pm #

    What happens if we decrease the price? Why does the demand evaporate?

  11. riz can February 6, 2013 at 3:21 am #

    thanks for this post. It added knowledge to, it helped me, especially on my report. Thanks again.


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