Milwaukee’s FORGE batteries are the latest evolution of the M18 platform, designed to deliver more power, longer life, and better durability than standard REDLITHIUM packs. Here’s everything you need to know about the FORGE lineup and whether it’s worth upgrading.
What Is Milwaukee FORGE?
FORGE is Milwaukee’s premium battery line within the M18 system. The key innovation is a new cell format — FORGE batteries use larger-format cells with tabless cell architecture, which reduces internal resistance. Lower resistance means less heat, more efficient power delivery, and a longer overall lifespan.
Milwaukee positions FORGE as the successor to their HIGH OUTPUT batteries, targeting professional tradespeople who push their tools hard every day.
FORGE Battery Lineup
M18 FORGE 6.0Ah (48-11-1861):
Capacity: 6.0Ah
Weight: 0.77 kg
Best for: All-day use on high-drain tools — rotary hammers, grinders, circular saws
Key feature: Up to 50% more power than standard M18 6.0Ah REDLITHIUM
M18 FORGE 8.0Ah (48-11-1880):
Capacity: 8.0Ah
Weight: 0.95 kg
Best for: Maximum runtime for sustained high-demand work
Key feature: Highest capacity M18 battery available
M18 FORGE 3.0Ah Compact:
Capacity: 3.0Ah
Weight: 0.45 kg
Best for: Compact tools, overhead work, impact drivers
Key feature: FORGE performance in a compact form factor
FORGE vs REDLITHIUM HIGH OUTPUT vs Standard REDLITHIUM
Milwaukee now has three tiers of M18 battery:
Standard REDLITHIUM — The baseline. Reliable, affordable, good for light to moderate use. These are the batteries typically bundled with tool kits.
REDLITHIUM HIGH OUTPUT (HD) — Upgraded cells that deliver more sustained power. Noticeable improvement on demanding tools like circular saws and angle grinders. The current mid-range option.
FORGE — The premium tier. New cell architecture delivers the most power and longest lifespan. Up to 50% more power than standard REDLITHIUM and designed to maintain performance longer as the battery ages.
Are FORGE Batteries Compatible with Existing M18 Tools?
Yes — fully backward compatible. FORGE batteries use the same M18 battery interface as every Milwaukee M18 tool ever made. They work in any M18 tool, from a first-generation drill to the latest M18 FUEL models. Your existing M18 batteries also continue to work in all your tools — FORGE is simply an additional option, not a replacement platform.
Is FORGE Worth the Upgrade?
Upgrade to FORGE if:
- You’re a professional using M18 FUEL tools daily and want the best possible performance
- You use high-drain tools (grinders, rotary hammers, circular saws) and notice performance drop-off with current batteries
- You want batteries that maintain their capacity longer over years of use
Stick with HIGH OUTPUT or standard REDLITHIUM if:
- You’re a DIYer or light-use professional — the performance gains won’t be noticeable on drills and impact drivers
- You need batteries in bulk and want to keep costs manageable
- Your current HIGH OUTPUT batteries are still performing well
Where to Buy
Search for Milwaukee FORGE batteries on Amazon UK
For a full comparison of every M18 battery option, see our guide: Every Milwaukee M18 Battery Compared.
Related Guides
- Every Milwaukee M18 Battery Compared
- Every Milwaukee M18 Tool and Which Batteries Fit
- Milwaukee M18 Charger Compatibility Guide
- Milwaukee M18 vs M18 FUEL
Video Guide
Frequently Asked Questions
FORGE vs Standard M18 Batteries in Practice
Milwaukee FORGE batteries represent the next generation of M18 battery technology. Using large-format cells instead of the standard 18650 cylindrical cells found in traditional M18 batteries, FORGE packs deliver substantially more power and better thermal management.
The most immediate real-world difference is sustained performance under heavy load. When pushing a FUEL circular saw through hardwood or running a FUEL grinder continuously, FORGE batteries maintain peak power delivery significantly longer than equivalent-capacity High Output batteries. This translates to faster cuts, fewer slowdowns, and more work completed per charge.
FORGE batteries also charge faster due to their improved thermal characteristics. The larger cell format dissipates heat more efficiently, allowing the charger to push more current without triggering thermal protection cutbacks. A FORGE battery reaches full charge noticeably faster than a standard High Output battery of the same capacity.
Should You Upgrade to FORGE?
Upgrade if: You use M18 FUEL tools professionally for demanding applications like concrete cutting, sustained grinding, heavy framing, or all-day site work. The improved power delivery and faster charging directly translate to productivity gains that justify the premium cost.
Wait if: You primarily use M18 tools for standard drilling, driving, and light cutting tasks. Current High Output and XC batteries deliver excellent performance for these applications, and the FORGE premium is harder to justify for lighter-duty use.
All FORGE batteries are fully backwards-compatible with existing M18 and M18 FUEL tools. You do not need new tools to benefit from FORGE batteries. However, Milwaukee is releasing FORGE-optimised tools that take full advantage of the improved power delivery, so the performance gap between FORGE and standard batteries may widen as the platform matures.
What makes Milwaukee FORGE batteries different?
FORGE batteries use a new cell format and chemistry that delivers higher sustained power output, faster charging, and better thermal management than previous REDLITHIUM batteries. The cells are designed for extreme-demand applications and can sustain higher current draw for longer periods without overheating or throttling.
Are FORGE batteries compatible with older M18 tools?
Yes. FORGE batteries are fully backward compatible with every M18 tool ever made. You get improved performance in FUEL tools and at least equivalent performance in standard M18 tools. There is no compatibility concern — FORGE is a drop-in upgrade for any M18 battery.
Is FORGE replacing REDLITHIUM HIGH OUTPUT?
FORGE is the newest tier in Milwaukee’s battery lineup and sits above HIGH OUTPUT. Milwaukee has not announced discontinuation of HIGH OUTPUT batteries. For most users, HIGH OUTPUT batteries remain an excellent choice. FORGE is targeted at professionals with the most demanding applications who need every bit of extra performance.
Frequently Asked Questions
No single brand wins across every category. Your best choice depends on which tools you already own — switching platforms is rarely worth the cost.
Is Milwaukee FORGE worth the extra cost?
For professionals using high-demand tools daily, yes. FORGE batteries deliver significantly more power and longer life than standard REDLITHIUM. For occasional users, standard M18 batteries offer better value.
Do FORGE batteries work in all M18 tools?
Yes. FORGE batteries are fully backward-compatible with all Milwaukee M18 tools. They provide the biggest performance gains in high-draw tools like grinders and circular saws.
How long do FORGE batteries last?
Milwaukee claims FORGE batteries last significantly longer than standard packs, with improved cycle life and better performance retention over time thanks to their tabless cell design.
