Mike Sievert
President and Chief Executive Officer at T-Mobile US
Okay. Thanks, Jud. Hi, everybody. It is so great to be coming to you live from our Bellevue, Washington headquarters here, all gathered together with increasing numbers of our employees with each passing week. And it's just great to feel the energy of this team. And it's no doubt fueled by this quarter's fantastic results.
T-Mobile delivered another outstanding quarter of profitable and industry-leading growth, beating our numbers across the board and leading the industry in postpaid net subscriber growth and service revenue growth yet again. And we did it while simultaneously delivering record core adjusted EBITDA and free cash flow above expectations, all of this while accelerating the transition of Sprint customer traffic onto the T-Mobile network, further extending our 5G network lead and increasing our expected merger synergies for the year. And these results all culminate in a 16% year-over-year increase in free cash flow, 16%, which is just the beginning of our rapid free cash flow expansion journey and the unlocking of massive shareholder value.
Listen, we're just past halftime in the game here for 2021 and our team is feeling more confident than ever. So we're increasing our guidance expectations across the board with today's announcement. Net additions, core EBITDA, synergies, capex investments and cash flow outlooks for the year are all being increased today. These results stem from our focus on executing on our three core ambitions that I talked with you about before, delivering industry-leading profitable growth by expanding our addressable market and growing customer relationships, delivering substantial enterprise value by realizing merger synergies faster and bigger while transforming our business and positioning the company for long-term success with sustained 5G leadership, our strong brand and the best customer experiences.
Let's start by talking about growth. Our 1.3 million postpaid nets were the best in the industry and we continue to lead the industry in postpaid phone growth year-to-date as well, adding another 627,000 postpaid phone net adds in Q2, above our plan and consensus. This include another strong quarter of growth from T-Mobile for business, driven by customer wins in key industries, including airlines, automotive and retail and government agencies such as the Department of Veteran Affairs and the US Army.
But importantly, our reliable profitable growth is the product of our progress on churn. T-Mobile again produced the biggest sequential improvement in postpaid phone churn compared to all other wireless operators this quarter, delivering 0.87%. We continue to make great strides in improving churn for both our T-Mobile and Sprint customers by providing them with best-in-class experiences. And we continue to see the lowest churn in the entire industry from our loyalty mobile branded customers. Our T-Mobile brand's consumer churn is lower than Verizon's and this quarter, so is our business journey [Phonetic].
This achievement is a testament to our awesome customer-loving team and also to our synergy-backed model, which allows us to sustainably deliver the best value, while rapidly building fame as America's best 5G network. And unlike the other guys, we've got room to run our higher Sprint churn is rapidly improving, giving us ongoing potential tailwinds in this area.
Speaking of our customer-loving team, just this morning, we were awarded the number one ranking from J.D. Power in US Customer Care Performance for the 22nd time. And our Net Promoter Score for customer care among our Sprint customers is up 48% year-over-year. The way we care for our customers is part of our secret sauce and it's important moat around our business.
Now with all the line growth we've been seeing in the industry, another strong metric to watch is postpaid accounts, which represents new overall customer building relationships. As we said during our Analyst Day, our strategy is built upon establishing new account relationships and growing them over time with additional products and services to drive ARPA growth.
This quarter, we delivered our highest ever postpaid account growth at 349,000 and we continue to focus on capturing quality profitable growth. I'll say it again. This quarter's account growth was our highest ever at least in all the years I've been here. That's over 600,000 net postpaid accounts added year-to-date compared to Verizon, which is still negatives for so far this year and AT&T who doesn't want to share account growth information.
In addition, we are a largest prepaid provider in the country. And we're consistently growing and delivering strong ARPUs in this valuable customer segment despite our size and despite the ongoing industry growth of postpaid at the expense of prepaid. In Q2, we delivered 76,000 net adds, which reflected record low industry-leading prepaid churn of just 2.62%.
Okay, let's discuss the financial outcomes. One thing that continues to distinguish us as an investment is that only T-Mobile is converting that record service revenue and our synergy-backed model in the industry-leading core EBITDA -- adjusted EBITDA, free cash flow growth. What's even more exciting is that we are delivering these results before we begin to fully capitalize on our 5G leadership and before we fully tap into the new market opportunities and underpenetrated segments we've been discussing.
Peter will tell you more about our financial results here in a minute, but what I'll say is that T-Mobile showed again today that we consistently deliver smart growth on the top-line metrics, while consistently leading on financial outcomes like core EBITDA and cash flow, pacing nicely to unlock the massive cash flows we outlined in our five-year plan, a plan that promised outcomes we are reiterating here today, built around consistent disciplined market-leading profitable growth.
Our opportunities are enabled by the fact that we already have America's largest, fastest and most reliable 5G network. And as we continue to pull further away from the pack with the pace of our network build, we're clearly beginning to differentiate ourselves not just on 5G but on network performance overall. Already this year, seven third-party network report show that T-Mobile customers get the fastest 5G speeds and spend the most time connected to 5G. While others are touching to the work of a single paid consultant to support their network claims, our 5G leadership is showing up loud and clear time and again and reports that are coming from multiple, independent, industry-leading firms that look at real customer usage from billions of device measurements.
Now I know we all spend a lot of time talking about 5G and for good reason, but we have also quietly eliminated the legacy advantages that AT&T and Verizon previously enjoyed on LTE, which is where most traffic remains today. In fact, the latest Ookla data shows that T-Mobile customers get the fastest overall network speeds nationwide and T-Mobile swept every mobile category in Ookla's latest report. This is in addition to OpenSignal's latest findings that T-Mobile delivers the best 4G availability. And Umlaut's latest report, which highlights again that T-Mobile has the most reliable network overall. So whether customers are on 4G LTE or 5G, they're covered by a far-reaching and speedy network at T-Mobile.
Speaking of far-reaching, did all of you touched Neville's blog earlier this week, he announced that T-Mobile's extended range 5G now reaches 305 million people, that's nearly everybody. And we surpassed our year-end milestone roughly six months ahead of schedule, thanks to the terrific momentum of our team. Think of it this way. Our 5G network covers 92% of Interstate Highway miles across 5G -- across America. With 5G, 92% today compared to just 68% for AT&T and only 51% for Verizon as an example. However, where we are really unlocking transformative experiences for our customers is with our game-changing Ultra Capacity 5G, which as you know, we are rolling out at an unprecedented pace.
We already cover half of the US population delivering average download speeds of 350 megabits per second to 165 million people with Ultra Capacity 5G. And we continue to increase both the breadth and depth of our mid-band deployment providing a 50% increase in our customers' average 5G download speeds just since the beginning of this year, according to billions of real-time device measurements by OpenSignal. That's because we're not just rolling out Ultra Capacity 5G to more of the population targeting 200 million people by year-end, but we are also adding spectrum targeting 100 megahertz before year-end, about what AT&T and Verizon will light up sometime next year with C-band combined.
We're well ahead in our 5G leadership. But what I hope is also becoming increasingly clear is that T-Mobile is positioned to maintain our 5G leadership for the duration of the 5G era, thanks to our superior spectrum portfolio, our unprecedented deployment momentum and our synergy-backed model. We're doing just what we've said we would do during the merger process, leading America into the 5G era and doing it without leaving rural areas behind. And this leadership is beginning to really matter to customers. The 5G era is here and seven out of 10 customers say they're excited about it. T-Mobile's 5G network perception is rapidly changing. And just since March, T-Mobile has seen a 25% increase in people viewing us as the leader in 5G. Now at 26%, we're closing in on Verizon's stagnant 35% number on this metric. And we're way ahead of AT&T.
And as for business customers, already over 40% of enterprise decision makers think of T-Mobile as a leader in 5G with 5G quickly becoming one of the top things that customers say they're looking for in their next wireless provider. Our network is increasingly becoming a catalyst for them to choose T-Mobile. This network progress is also helping to fuel the rapid realization of merger synergies and our continued progress on integration. For the second quarter in a row, we're raising our synergy guidance for 2021. This progress includes continuing to migrate Sprint customers to the T-Mobile network and improve their experience, which is key to unlocking synergies. We've already moved one-third of Sprint customers to the T-Mobile network. And this is important. We're now carrying approximately 80% of the total Sprint customer traffic on the T-Mobile network. This is all within just five quarters of closing the merger.
And as planned, we're also expanding into new and underpenetrated businesses. We commercially launched our broad 5G Home Internet offering at the beginning of the second quarter. We continue to see great customer satisfaction and product demand continues to put us on track for our target of 500,000 Home Internet customers this year even with demand exceeding our supply for modems at times earlier this year. And we're already seeing third-party recognition, including PC Magazine recently publishing it's Readers' Choice Awards, where T-Mobile Home Internet is ranked higher than every single cable provider by actual customers for overall satisfaction and likelihood to recommend.
For enterprise and government, our plan is built on taking share in core wireless, and it's well on track as I discussed earlier. But in addition, our 5G network creates a platform for growth beyond core wireless. And we are focused on helping customers realize value from emerging technologies such as private networks and mobile edge compute, which are exciting potential upsides to our plan. We're already in trial programs with major enterprises in these areas, including 12 of the Fortune 50, even though we don't issue empty press releases about it every week. Meanwhile, we're building our best value, best network, best customer experiences formula to smaller markets and rural areas as well, which make up 40% of US households.
We've kicked off initiatives to add significantly more points of distribution to reach beyond urban areas as well as new initiatives and offers. We're already seeing some early success as smaller markets and rural areas drove nearly one-third of our new postpaid account activations in Q2, up from about a quarter last year. The potential here is super-exciting.
So, if I get ready to turn it over to Peter to take you through our financials, I want to take a moment to thank our team for delivering another remarkable quarter, delivering the highest postpaid customer growth and service revenue growth in the industry, while translating that into the highest core adjusted EBITDA and free cash flow growth in the industry. We continue to execute our integration playbook to unlock merger synergies ahead of schedule and we further expanded our 5G lead with the nation's largest, fastest and most reliable 5G network, planting the seeds for our future success.
So, okay, let me turn it over to Peter to take you through the financials and our guidance.