4.0Ah vs 5.0Ah vs 5.5Ah
Same fit: these run the same tools
Lowest price we track at UK retailers, updated daily. We may earn a commission
They differ in 4 of 5 areas
Same tools, so this is about size, weight and cost. No overall winner: pick the size that suits the job.
EnergyThe 5.5Ah stores 38% more than the 4.0Ah: 99Wh vs 72Wh.
WeightThe 4.0Ah is the lightest at 0.7kg, the 5.5Ah the heaviest at 1.1kg.
PriceThe 4.0Ah is the cheapest of the three today, at £57.95.
Price per Ah5.0Ah £11.99, 4.0Ah £14.49, 5.5Ah £18.17.
Good to know
Same toolsAll three fit every Milwaukee M18 tool.
Same chargersM12-18FC, M18DFC, M18PC6, M18DBSC, M18MDBSC, M18MPC6, M12-18GBC4, M12-18AC, M1418C6, M1418C6-110V and M18TC charge all three. Charge times are in the specs below.
Energy
M18B4
72Wh
M18B5
90Wh
M18HB5.5
99Wh
Maker figure, or volts × Ah where they don't publish one. Ah and Wh explained ›
Weight
M18B4
0.7kg
M18B5
0.7kg
M18HB5.5
1.1kg
Price per Ah
M18B4
£14.49
M18B5
£11.99
M18HB5.5
£18.17
Lowest price we track ÷ Ah. Full specs
M18B4M18B5M18HB5.5
Voltage18V18V18V
Capacity4.0Ah5.0Ah5.5Ah
Energy72Wh90Wh99Wh
Weight0.7kg0.7kg1.1kg
Energy for its weight103Wh/kg (worked out)129Wh/kg (worked out)90Wh/kg (worked out)
ChemistryLi-ion (cylindrical)Li-ion (cylindrical)Li-ion (cylindrical)
Cell typeNot listedNot listedNot listed
Fuel gaugeYesYesYes
Size (L × W × H)Not listedNot listedNot listed
Charge time, M12-18FC, M18DFC, M18PC6, M18MPC6, M12-18GBC452 min59 min1 hr
Charge time, M18DBSC, M18MDBSC52 min59 min35 min
Charge time, M12-18AC1 hr 20 min1 hr 40 min2 hr 10 min
Charge time, M1418C6, M1418C6-110V1 hr 20 min1 hr 40 min2 hr 5 min
Lowest price£57.95£59.95£99.95
Specs from each maker's own documentation. "Not listed" means the maker doesn't publish it or we haven't found it yet; it never counts as a difference.
Battery guides
Not sure what the numbers mean, or which platform to buy into? Start here.
Power Tool Battery Ah and Wh ExplainedEvery battery gives an "Ah" number: 2.0Ah, 5.0Ah, 8.0Ah. People treat it like a power rating, buy the biggest one they can,…5 Min Read min read ›
Cordless Battery Platforms Explained: Which Should You Buy Into?Here is the thing no one tells you when you buy your first power tool: you are not really choosing a tool.…8 min read min read ›
Corded vs Cordless Power Tools: Which to Buy?Cordless has taken over site and workshop, and for good reason, but corded tools are not dead, and for some jobs they…5 min read min read ›