Reporting Methodology & The Saturday Anchor Rule
The BLK Bestsellers List compiles point-of-sale retail book sales data in 7-day cycles starting on Sunday morning and ending at Saturday midnight.
The Saturday Anchor Rule
Because sales figures are aggregated in weekly chunks, a single week's sales are never split across calendar months. An entire week's sales volume is assigned to the reporting month anchored by the ending Saturday. For example, the July 2026 BLK list reflects sales tracked from June 07, 2026 through July 04, 2026, while the August 2026 list covers July 05, 2026 through August 01, 2026.
Key Calendar Rules for Publishers & Authors:
- 4-Week vs. 5-Week Months: Depending on how Saturdays land in the calendar, a BLK Bestseller reporting period consists of either 4 weeks (28 days) or 5 weeks (35 days).
- Cross-Month Weeks: A sales week running from June 28 to July 04 is counted in the July reporting period because July 4th is the Saturday anchor date.
- Standardization: AALBC's monthly BLK Bestsellers list aligns strictly with these periods to guarantee complete data fidelity across point-of-sale reports.
BLK Reporting Periods (February 2024 – December 2028)
Select a year to view exact sales tracking date ranges and weekly counts:
| BLK Bestseller Month | Sales Tracking Period (Sun – Sat) | Reporting Weeks |
|---|---|---|
| January 2025 | Dec 08, 2024 – Jan 04, 2025 | 4 Weeks |
| February 2025 | Jan 05, 2025 – Feb 01, 2025 | 4 Weeks |
| March 2025 | Feb 02, 2025 – Mar 01, 2025 | 4 Weeks |
| April 2025 | Mar 02, 2025 – Apr 05, 2025 | 5 Weeks |
| May 2025 | Apr 06, 2025 – May 03, 2025 | 4 Weeks |
| June 2025 | May 04, 2025 – Jun 07, 2025 | 5 Weeks |
| July 2025 | Jun 08, 2025 – Jul 05, 2025 | 4 Weeks |
| August 2025 | Jul 06, 2025 – Aug 02, 2025 | 4 Weeks |
| September 2025 | Aug 03, 2025 – Sep 06, 2025 | 5 Weeks |
| October 2025 | Sep 07, 2025 – Oct 04, 2025 | 4 Weeks |
| November 2025 | Oct 05, 2025 – Nov 01, 2025 | 4 Weeks |
| December 2025 | Nov 02, 2025 – Dec 06, 2025 | 5 Weeks |
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