You may hear us refer to a term called "QCI" in discussions about data plans, throughput, and priorities when using various SIM cards and plans. Let's dig into what QCI levels are and how they affect your mobile experience.
Quality of Service Class Identifier (QCI) levels are how mobile networks manage and prioritize different types of data traffic, making sure critical services get the performance they need. In 5G, the equivalent is called 5QI (5G QoS Identifier). So far, the 5QI value on a given plan has matched its LTE QCI, so the two can be treated the same for now.
How QCI works
QCI is a set of predefined values that determine how traffic is prioritized on the network. Each value maps to a quality-of-service class defining things like latency, packet loss, and error rates, so the network can tell voice calls apart from video, browsing, and background apps. Traffic falls into two broad categories:
- Guaranteed Bit Rate (GBR): for services that need a dedicated slice of bandwidth (for example, VoLTE voice).
- Non-Guaranteed Bit Rate (Non-GBR): for services that tolerate fluctuating bandwidth (for example, web browsing or background apps).
Common QCI levels
- QCI 1: VoLTE voice. GBR, high priority, low latency.
- QCI 5: IMS signaling (call setup and messaging). Non-GBR, high priority.
- QCI 6: high-priority data on some carriers (see T-Mobile below).
- QCI 7: conversational/real-time data and premium data tiers on some carriers.
- QCI 8 and 9: general mobile internet (browsing, social, apps). QCI 9 is the lowest, default priority for general traffic.
The key rule: higher QCI numbers mean lower priority. Beyond these, higher-priority classes exist for things like phone calls and are generally universal across a carrier's plans.
Important: deprioritization is not a throttle
This is the part people most often misunderstand. Being on a lower-priority QCI (like QCI 9) is not a speed cap. It only matters when the tower in your area is congested. If nobody else is competing for the airwaves, a QCI 9 plan can hit the full speed the network can deliver. When the cell is busy, higher-priority traffic goes first.
QCI also affects latency, not just speed. Under congestion it's common to see prioritized traffic at roughly 20 to 50 ms while deprioritized traffic on the same tower sees 100 to 150 ms, even when both post similar speed-test numbers, because the prioritized packets are served first.
Data prioritization by carrier
Heads up: this is crowdsourced information that can and will change. The carrier, plan, and QCI details in this article are compiled from community-maintained sources, primarily u/Ethrem's data prioritization guide on r/NoContract. Carriers change plan priorities frequently, often without any announcement, so treat everything below as a helpful reference rather than a guarantee. If a specific plan's priority level is critical to you, verify it directly with the carrier.
Below is a current breakdown of how the three major U.S. networks assign QCI to consumer, business, first-responder, and MVNO plans. Business and MVNO plans change frequently, so treat this as a strong guide rather than a guarantee, and verify for a specific plan if it's critical.
Verizon (uses QCI 7, 8, 9)
- QCI 7: reserved exclusively for Verizon Frontline (first responders). For everyone else, this level effectively doesn't exist.
- QCI 8: Verizon Business Plus 5G, Business Pro 5G, and My Biz with the Premium Network Experience add-on; consumer postpaid plans (except Welcome Unlimited); Xfinity Mobile; Spectrum Mobile. US Mobile Warp 5G gives QCI 8 on 5G devices if you have Unlimited Premium (or were a customer before 8/18/2025). Visible+ and Visible+ Pro are unlimited QCI 8. Total Wireless Total 5G Unlimited and Total 5G+ Unlimited include unlimited priority data. MobileX offers a paid QCI 8 add-on (it is QCI 9 without it).
- QCI 9: everything else. The Start 5G business plan, My Biz without the add-on, branded prepaid (except Unlimited Plus), Visible's base plan, US Mobile Warp 5G Unlimited Starter (a QCI 8 add-on is coming), Unlimited Flex and By the Gig without the QCI 8 add-on, Mobi, and other prepaid brands on Verizon's network. Anyone who exhausts their premium data bucket drops to QCI 9.
TracFone brands (SafeLink, Straight Talk, etc.) are inconsistent: some lines get priority data and others are deprioritized, seemingly at random, so don't count on priority data there if you truly need it.
AT&T (uses QCI 6, 7, 8, 9)
- QCI 6: FirstNet with primary status, grandfathered Business Unlimited Premium, and some corporate-responsibility plans.
- QCI 7: Business Unlimited Premium 2.0 with Turbo; Unlimited Premium PL, Unlimited Extra EL, and AT&T Prepaid Unlimited Max Plus lines that pay $7 for AT&T Turbo; and FirstNet extended-primary plans. (US Mobile is adding QCI 7 as a paid add-on for Unlimited Premium.)
- QCI 8: Business Unlimited Advanced, Business Unlimited Premium 2.0 (without Turbo), Unlimited Extra EL, Unlimited Premium PL, Prepaid Unlimited Max, Prepaid Unlimited Max Plus, the $300 AT&T Prepaid annual plan (16GB high-speed), Cricket Supreme Unlimited, Cricket Sensible 10GB, and plans from H2O, Consumer Cellular, and PureTalk. US Mobile Dark Unlimited Premium is also QCI 8.
- QCI 9: Business Unlimited Starter, the base Unlimited plans (postpaid and AT&T Prepaid), Cricket Select Unlimited, Cricket Smart Unlimited, other known MVNOs, and all AT&T brands once their premium data buckets are exhausted. US Mobile Dark Star plans (other than Unlimited Premium) default to QCI 9, though Unlimited Flex and By the Gig have paid QCI 8 add-ons.
T-Mobile (uses QCI 6, 7, 9 for phone plans)
- QCI 6: all branded plans, postpaid and prepaid, except those with "Essentials" in the name. Google Fi is QCI 6 as well.
- QCI 7: Essentials-branded plans and all other known MVNOs.
- QCI 8: not used for phone plans. It's used for on-device hotspot and for data-only plans with 30GB or more.
- QCI 9: lines that have exhausted their data bucket. The T-Mobile Mobile Internet 30GB plan is also QCI 9.
5G and 5QI
On 5G, QCI is replaced by 5QI (5G QoS Identifier), which follows the same principles with more granularity and supports advanced 5G use cases (ultra-reliable low-latency, massive IoT, enhanced mobile broadband). In practice, the plans we've seen assign the same 5QI value as their LTE QCI, so the tables above still apply.
Why this matters for your connectivity
If you rely on cellular for critical connectivity, especially in busy areas or at events, the QCI of your SIM plan can matter as much as the "unlimited" label on it. When bonding or failing over multiple cellular links on a Peplink device, mixing plans with different priority levels affects how each link performs under congestion. Llama Networks can help you match SIMs and plans to your priority needs. Reach out to sales[at]llamanetworks[dot]com.