Every cordless grease gun gets a score from 0 to 100% built from six factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Guns are grouped into tool only (no battery or charger) and kits (with a battery and charger), and each group has its own price scale.
| Factor | Measures | Weight |
|---|---|---|
| Value | price, on a separate scale for tool-only guns and kits | 25% |
| Flow | top grease flow in oz per minute | 25% |
| Hose | length of the hose in the box | 15% |
| Pressure | maximum pressure, full marks at 10,000 psi | 10% |
| Runtime | cartridges per battery charge, as stated by the maker | 10% |
| Warranty | tool warranty length | 15% |
Where the numbers come from
Flow, pressure, hose length, cartridges per charge, battery details and warranty come from the maker’s product page, manual or brochure, or from the maker’s own copy on a retail listing. Where a maker’s figures conflict (for example a title that gives one pressure and a bullet that gives another), the product is left out rather than guessed. Flow given in grams per minute is converted at 28.35 g per oz, and a hose given in centimetres or metres is converted to inches. Prices are checked at the stores each page links to, and the lowest is used.
The factors
Value is the current price on a log scale, so halving the price always counts the same. A kit’s price pays for a battery and charger that a bare tool leaves out, so the two groups use different scales: for a bare tool, $250 scores zero and $60 full marks; for a kit, $500 scores zero and $100 full marks. Guns are only ranked against others in the same group.
Flow is the maker’s top grease flow in oz per minute, on the faster setting where there are two: 3 oz per minute scores zero and 10 oz full marks. Flow is the figure that separates these guns most, so a gun whose maker doesn’t publish it scores zero for flow and is marked estimated, rather than getting a middle score it may not deserve.
Hose is the length of the hose in the box: 18 in scores zero and 48 in full marks. A longer hose reaches fittings behind wheels and under frames without moving the gun.
Pressure is the maker’s maximum pressure: 6,000 psi scores zero and 10,000 psi full marks. Ratings above 10,000 psi score no higher, since higher claims are hard to compare and 10,000 psi is the common rating among the major brands.
Runtime is the number of 14 oz cartridges the maker says one battery charge pumps: 5 scores zero and 25 full marks. Makers state this for different battery sizes, and the battery it was stated for is noted on each product page.
Warranty is the maker’s tool warranty: 1 year scores zero and 5 years full marks.
What isn’t scored
Battery system, voltage, the number and size of kit batteries, weight, speed settings, lock-on trigger, work light, output display, carrying case and release date are listed but not scored.
Missing data
If hose length or cartridges per charge isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. Flow, pressure and warranty are the exceptions: a gun whose maker doesn’t publish one of them scores zero for that factor, the same as the low reference point, and it is marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.