Finding “reliable” data about the installed base of Internet of Things (IoT) devices, market size and forecasts is not easy and can be expensive if you have to buy a commercial market report. However, there is quite a bit of free data out there which I have collated here. Creating IoT stats is notoriously difficult depending on accuracy of models, assumptions and definitions. Forecasts need to be treated very cautiously. However, by looking through a range of estimates from different providers it should be possible to get a rough idea of how the IoT market may look in the next few years. I have focused on providing links to the original sources where possible.
Feel free to contact me if I have missed anything and I’ll amend the list. (Updated 5 December 2019)
Internet of Things Statistics
Title: Gartner Says 5.8 Billion Enterprise and Automotive IoT Endpoints Will Be in Use in 2020
Date: 29 August 2019
Author: Gartner
Summary: “Gartner, Inc. forecasts that the enterprise and automotive Internet of Things (IoT) market will grow to 5.8 billion endpoints in 2020, a 21% increase from 2019. By the end of 2019, 4.8 billion endpoints are expected to be in use, up 21.5% from 2018.”
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Title: IDC Forecasts Worldwide Spending on the Internet of Things to Reach $745 Billion in 2019
Date: 3 January 2019
Author: IDC
Summary: “Worldwide spending on the Internet of Things (IoT) is forecast to reach $745 billion in 2019, an increase of 15.4% over the $646 billion spent in 2018, according to a new update to the International Data Corporation (IDC) Worldwide Semiannual Internet of Things Spending Guide. IDC expects worldwide IoT spending will maintain a double-digit annual growth rate throughout the 2017-2022 forecast period and surpass the $1 trillion mark in 2022.”
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Link: https://www.idc.com/getdoc.jsp?containerId=prUS44596319
Title: Gartner Identifies Top 10 Strategic IoT Technologies and Trends
Date: 7 November 2018
Author: Gartner
Summary: “Gartner forecasts that 14.2 billion connected things will be in use in 2019, and that the total will reach 25 billion by 2021, producing immense volume of data.”
Title: IDC Forecasts Worldwide Spending on the Internet of Things to Reach $772 Billion in 2018
Date: 7 December 2017
Author: IDC
Summary: “Worldwide spending on the Internet of Things (IoT) is forecast to reach $772.5 billion in 2018, an increase of 14.6% over the $674 billion that will be spent in 2017. A new update to the International Data Corporation (IDC) Worldwide Semiannual Internet of Things Spending Guide forecasts worldwide IoT spending to sustain a compound annual growth rate (CAGR) of 14.4% through the 2017-2021 forecast period surpassing the $1 trillion mark in 2020 and reaching $1.1 trillion in 2021.”
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Link: https://www.idc.com/getdoc.jsp?containerId=prUS43295217
Title: IDC Says Worldwide Spending on the Internet of Things Forecast to Reach Nearly $1.4 Trillion in 2021
Date: 14 June 2017
Author: IDC
Summary: “Worldwide spending on the Internet of Things (IoT) to grow 16.7% year over year in 2017, reaching just over $800 billion. By 2021, global IoT spending is expected to total nearly $1.4 trillion as organizations continue to invest in the hardware, software, services, and connectivity that enable the IoT.”
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Link: https://www.idc.com/getdoc.jsp?containerId=prUS42799917
Title: Gartner Says 8.4 Billion Connected “Things” Will Be in Use in 2017, Up 31 Percent From 2016
Date: 7 February 2017
Author: Gartner
Summary: “Gartner, Inc. forecasts that 8.4 billion connected things will be in use worldwide in 2017, up 31 percent from 2016, and will reach 20.4 billion by 2020. Total spending on endpoints and services will reach almost $2 trillion in 2017.”
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Link: http://www.gartner.com/newsroom/id/3598917
Title: Winning in IoT: It’s All About the Business Processes
Date: 5 January 2017
Author: Boston Consulting Group (BCG)
Summary: “Our analysis uncovered three major findings. One, there is no such thing as “the” Internet of Things: today’s market is heavily driven by specific use case scenarios. Two, while in the aggregate, companies will spend an incremental €250 billion on IoT in 2020 (over and above their normal technology spending), three industries will account for approximately 50% of that spending. And three, although all layers of the IoT technology stack are poised to grow through 2020, the layers are not equally attractive.”
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Title: Internet of Things Spending Forecast to Grow 17.9% in 2016 Led by Manufacturing, Transportation, and Utilities Investments, According to New IDC Spending Guide
Date: 4 January 2017
Author: IDC
Summary: International Data Corporation (IDC) released an update to its Worldwide Semiannual Internet of Things Spending Guide report, which predicted IoT spending will reach US$1.29 trillion in 2020
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Link: https://www.idc.com/getdoc.jsp?containerId=prUS42209117
Title: Machina Research expands the scope of its IoT forecasts and highlights a USD4 trillion revenue opportunity in 2025
Date: 3 May 2016
Author: Machina Research
Summary: “Machina Research comprehensively extends the coverage of its forecasts to include almost the entirety of the Internet of Things revenue opportunity, predicting it will rise from USD892 billion in 2015 to USD4 trillion in 2025.”
Graphic: n/a
Title: Gartner Says Worldwide IoT Security Spending to Reach $348 Million in 2016
Date: 25 April 2016
Author: Gartner
Summary: IoT security expenditure to 2018
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Link: http://www.gartner.com/newsroom/id/3291817
Title: Machina Research expands the scope of its IoT forecasts and highlights a USD4 trillion revenue opportunity in 2025
Date: 3 May 2016
Author: Machina Research
Summary: “Machina Research comprehensively extends the coverage of its forecasts to include almost the entirety of the Internet of Things revenue opportunity, predicting it will rise from USD892 billion in 2015 to USD4 trillion in 2025.”
Graphic: n/a
Title: IoT platforms: enabling the Internet of Things
Date: March 2016
Author: IHS
Summary: Forecast of global IoT installed base from 2015 to 2025
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Link: https://www.ihs.com/Info/0416/internet-of-things.html
Title: Cloud Index White Paper
Date: 21 April 2016
Author: Cisco
Summary: “Globally, the data created by Internet of Everything (IoE) devices will reach 507.5 ZB per year (42.3 ZB per month) by 2019, up from 134.5 ZB per year (11.2 ZB per month) in 2014.
● Globally, the data created by IoE devices will be 269 times higher than the amount of data being transmitted to data centers from end-user devices and 49 times higher than total data center traffic by 2019.”
Graphic: n/a
Title: IDC Forecasts Worldwide Shipments of Wearables to Surpass 200 Million in 2019, Driven by Strong Smartwatch Growth and the Emergence of Smarter Watches
Date: 17 March 2016
Author: IDC
Summary: “Worldwide shipments of wearable devices are expected to reach 110 million by the end of 2016 with 38.2% growth over the previous year. An expanding lineup of vendors combined with fast-growing consumer awareness and demand will generate double-digit growth throughout the 2015-2020 forecast period, culminating in shipments of 237.1 million wearable devices in 2020. The market will also be driven forward by the proliferation of new and different wearable products. Watch and wristband shipments will reach a combined total of 100 million shipments in 2016, up from 72.2 million in 2015.”
Graphic: n/a
Link: https://www.idc.com/getdoc.jsp?containerId=prUS41100116
Title: Gartner Says 6.4 Billion Connected “Things” Will Be in Use in 2016, Up 30 Percent From 2015
Date: 10 November 2015
Author: Gartner
Summary: “Gartner, Inc. forecasts that 6.4 billion connected things will be in use worldwide in 2016, up 30 percent from 2015, and will reach 20.8 billion by 2020. In 2016, 5.5 million new things will get connected every day.
Gartner estimates that the Internet of Things (IoT) will support total services spending of $235 billion in 2016, up 22 percent from 2015.”
Graphic: n/a
Link: http://www.gartner.com/newsroom/id/3165317
Title: IC Insights Raises Growth Forecast for IoT
Date: 16 July 2015
Author: IC Insights
Summary: Global IoT revenues by segment from 2012 to 2015
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Link: http://www.icinsights.com/news/bulletins/Internet-Of-Things-Market-To-Nearly-Double-By-2019-/
Title: The Internet of Things: “Smart” Products Demand a Smart Strategy
Date: March 2015
Author: Woodside Capital Partners
Summary: Large (101 pages) PDF with lots of data from different sources.
Graphic: 
Link: http://www.woodsidecap.com/wp-content/uploads/2015/03/WCP-IOT-M_and_A-REPORT-2015-3.pdf
Title: Internet of things: making the most of the second digital revolution
Date: 18 December 2014
Author: UK Government
Summary: The downloadable PDF contains some useful comparisons of estimates from the main IoT vendors and analysts. See pages 14 and 20
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Link: https://www.gov.uk/government/publications/internet-of-things-blackett-review
Title: The Internet of Things: Sizing up the opportunity
Date: December 2014
Author: McKinsey & Co.
Summary: Installed base forecast to 2020 and value to global economy for 2025
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Link: http://www.mckinsey.com/industries/high-tech/our-insights/the-internet-of-things-sizing-up-the-opportunity
Title: The ‘Internet of Things’ Will Be The World’s Most Massive Device Market And Save Companies Billions Of Dollars
Date: 18 November 2014
Author: Business Insider
Summary: Estimates of global installed base and annual growth to 2019
Graphic: 
Link: http://uk.businessinsider.com/how-the-internet-of-things-market-will-grow-2014-10?r=US&IR=T
Title: What Exactly is the Internet of Things?
Date: March 2014
Author: Harbor Research
Summary: Slideshare deck with data on IoT devices shipments by sector and revenue estimates for those segments to 2020.
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Title: The Internet of Things: How the Next Evolution of the Internet Is Changing Everything
Date: April 2011
Author: Cisco
Summary: Downloadable PDF. Forecasts 50 billion connected devices by 2020
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Link: http://www.cisco.com/c/dam/en_us/about/ac79/docs/innov/IoT_IBSG_0411FINAL.pdf
Other Resources:
[…] deal of data is available that speculates on the rate at which the worldwide market may continue to grow. The International Data Corporation estimates, for example, that the worldwide IoT market of […]