> For the complete documentation index, see [llms.txt](https://knowledge.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://knowledge.illumina.com/instrumentation/general/instrumentation-general-reference_material-list/000008320.md).

# RTA4 Q Score Bin Ranges on the NovaSeq X Series

**Background**

The NovaSeq X Series utilizes Real Time Analysis v4 (RTA4) for base calling and quality scoring. There are three Q score bins used on the NovaSeq X Series, and these Q score calls are reported as an average for the range of called scores. See below for the relevant Q Score Bins and Ranges, depending on Control Software version.

**Table 1.** Control Software v1.4 ([NovaSeq X Series Software 1.4.0 Customer Release Notes](https://support.illumina.com/content/dam/illumina-support/documents/downloads/software/novaseq-x-series/200079828_00_NovaSeq_X_Series_1_4_0_Release_Notes.pdf))

<table data-header-hidden><thead><tr><th valign="top"></th><th valign="top"></th></tr></thead><tbody><tr><td valign="top">Bin</td><td valign="top">Q Score Range</td></tr><tr><td valign="top">2</td><td valign="top">NoCall, 0-2</td></tr><tr><td valign="top">9</td><td valign="top">3-17</td></tr><tr><td valign="top">24</td><td valign="top">18-29</td></tr><tr><td valign="top">41</td><td valign="top">30+</td></tr></tbody></table>

**Table 2.** Control Software v1.3 ([NovaSeq X Series Software 1.3.0 Customer Release Notes](https://support.illumina.com/content/dam/illumina-support/documents/downloads/software/novaseq-x-series/200063726_00_NovaSeq_X_Series_Sequencing_System_1_3_0_Release_Notes.pdf))

<table data-header-hidden><thead><tr><th valign="top"></th><th valign="top"></th></tr></thead><tbody><tr><td valign="top">Bin</td><td valign="top">Q Score Range</td></tr><tr><td valign="top">2</td><td valign="top">NoCall, 0-2</td></tr><tr><td valign="top">9</td><td valign="top">3-17</td></tr><tr><td valign="top">24</td><td valign="top">18-29</td></tr><tr><td valign="top">40</td><td valign="top">30+</td></tr></tbody></table>

**Table 3.** Control Software v1.2 and v1.2.2

<table data-header-hidden><thead><tr><th valign="top"></th><th valign="top"></th></tr></thead><tbody><tr><td valign="top">Bin</td><td valign="top">Q Score Range</td></tr><tr><td valign="top">2</td><td valign="top">NoCall, 0-2</td></tr><tr><td valign="top">12</td><td valign="top">3-17</td></tr><tr><td valign="top">24</td><td valign="top">18-29</td></tr><tr><td valign="top">40</td><td valign="top">30+</td></tr></tbody></table>

For more information on changes to Q Score bins with Control Software v1.2, see the following Illumina article: [NovaSeq X v1.2 software enables sequencing with 80% of bases >= Q40](https://www.illumina.com/science/genomics-research/articles/data-quality-q-scores.html)

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