Makita BL4040 40V max XGT battery

BL4040 is a single 40V max XGT 4.0Ah pack. Single pack: BL4040F.

Published manufacturer specifications; sources last checked 2026-10-25.

Specifications

Voltage What this means Voltage identifies the battery platform. Some makers quote a peak (max) figure at the start of discharge while others quote nominal, so 18 V nominal and 20 V max packs usually have the same cell count. Higher-voltage platforms typically serve more demanding tools. Batteries only fit tools from the matching line.	40 V
Battery capacity (each) What this means Amp-hours (Ah) is the battery's charge capacity. At the same voltage, a higher Ah pack runs longer between charges but is usually larger and heavier. Smaller packs keep the tool lighter for overhead and light work; larger packs suit saws, grinders and other high-draw tools.	4.0 Ah
Battery line What this means Battery line is the maker's platform name, which determines which tools and chargers the pack fits. Makers generally keep one battery design across a platform, but batteries from different makers are not interchangeable. Buying into a line is often a longer-term choice than buying a single tool.	40 V max XGT
Dimensions (L x W x H)	5-1/4 x 3-1/4 x 2-13/16 in
UPC barcode	088381583664

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The battery itself. Makita's page does not list box contents.

Part of the Makita 40V max XGT system. See "Works with" for the maker's own compatibility statement.

Which tools does the BL4040 fit?: It is a Makita 40V max XGT system battery. Which batteries fit Makita 40V max XGT tools?
What voltage is the BL4040?: 40 V, as Makita publishes it.
How many Ah is the BL4040?: 4.0 Ah per battery, as Makita publishes it.
Which kits include the BL4040?: 3 kits on this site list the BL4040 by model number in Makita's box list: GAG01M1, GRJ02M1, GSH01M1.

Kits whose maker box list names the BL4040 by model number.

Every Makita 40V max XGT tool takes this system's batteries; capacity (Ah) changes run time, not fit.

Spotted a wrong number? Report a spec error (opens an email with the model filled in). We re-check against the maker's page and correct the page.