Mercury

1. Oct 2026

First measured October 2026.

1. Toast Electric, 0.78 MB
2. Electric Kiwi, 1.55 MB
3. Powershop, 1.57 MB
4. Meridian, 1.63 MB
5. Contact, 1.68 MB
6. Octopus Energy, 1.74 MB
7. Lodestone, 1.78 MB
8. Ecotricity, 2.01 MB
9. Grey Power Electricity, 2.32 MB
10. Genesis, 2.96 MB
11. Pulse, 3.75 MB
12. Nova, 3.93 MB
13. Mercury, 7.18 MB

1. B
2. D
3. D
4. D
5. D
6. D
7. D
8. E
9. E
10. F
11. F
12. F
13. G

LightestHeaviest

• Mercury

• Phone

  9.3 MB

• Laptop

  9.4 MB

First visitiReturningi

1. Homepage

   /

   First visit

   Phone 9.3 MB

   Laptop 9.4 MB

   Returning

   Phone 0.66 MB

   Laptop 0.45 MB

2. Plans

   /electricity

   First visit

   Phone 9.4 MB

   Laptop 9.4 MB

   Returning

   Phone 0.58 MB

   Laptop 0.45 MB

3. Moving house

   /moving-house

   First visit

   Phone 9.0 MB

   Laptop 9.4 MB

   Returning

   Phone 0.27 MB

   Laptop 0.21 MB

4. Power outages

   /help-and-support/outages-and-faults

   First visit

   Phone 9.4 MB

   Laptop 9.9 MB

   Returning

   Phone 0.59 MB

   Laptop 0.71 MB

5. Contact

   /help-and-support

   First visit

   Phone 9.0 MB

   Laptop 9.3 MB

   Returning

   Phone 0.11 MB

   Laptop 0.13 MB

• Mercury’s own files

  This website

  1.2 MB13%

• PowerFront

  Chat

  7.0 MB75%

• Google Tag Manager

  Tag manager

  0.53 MB6%

• Facebook

  Advertising and social

  0.28 MB3%

• 3 more companies

  ContentSquare, Analytics, 0.18 MB
  Evergage, Analytics, 0.05 MB
  The Trade Desk, Advertising and social, 0.02 MB

  0.24 MB3%

• Unknown source

  0.01 MB0%

• Images

  7.3 MB

• Scripts

  1.7 MB

• Styles

  0.17 MB

• Fonts

  0.13 MB

• Other

  0.05 MB

1. Image · PowerFront

   2-mercury-bot-idle.gif

   Every page

   4.1 MB

2. Image · PowerFront

   2-mercury-bot-intro.gif

   Every page

   1.1 MB

3. Image · PowerFront

   2-mercury-bot-outro.gif

   Every page

   0.92 MB

4. Image · Mercury

   Mercury-Award-Winning-Electricity-Provider-1400x293.png

   Electricity

   0.40 MB

5. Script · Google Maps

   maps.googleapis.com/maps/api/js

   Outages and Faults

   0.39 MB

Fix

Nothing a visitor would notice

Choice

Removes or delays something

Worked out on a phone and a laptop. The icons show where each saving applies.

1. Choice

   Load the chat only when someone opens it

   Every page · PowerFront

   up to 5.3 MB

2. Choice

   Google Maps (Utility): you choose whether it loads

   Outages and Faults · Google Maps

   0.49 MB

3. Choice

   Check every marketing tag still earns its place: 6 companies

   Every page · several companies

   up to 0.40 MB

4. Fix

   Ship less of your own code: scripts and styles that did not run while the homepage loaded

   Every page · Mercury

   up to 0.32 MB

5. Fix

   Resize 9 images to the size screens show them

   Every page · Mercury

   at least 0.13 MB

If this website had 100,000 page views a year, they would cause about 65 kg of carbon emissions.

Built to grade A (under 0.53 MB a page), the same page views would cause about 4.8 kg.

A grade C badge needs a typical page under 1.41 MB. Mercury’s is 7.18 MB.