Our goal at DIY Gear Reviews is to cut through the marketing hype and word-of-mouth anecdotal evidence to determine which tools are worthy of a spot in your tool belt, on the job site, or in your workshop.
We achieve our goal by testing tools more rigorously than any online review site and standardizing our testing methodologies to simplify comparing impact drivers across brands.
After running each impact driver in our test fleet through our standardized lab tests, we use that data to power our editorial ratings and impact driver rankings.
We detail the specifics of our rating methodology below so our community can best understand how we evaluate and determine the best impact drivers.
Factors assessed
After our in-house lab tests are complete, we compile the results and bucket key data points into eight categories outlined below. We then use these data points in our rating model to output a category rating. All category ratings are weighted and then summed to provide the final editorial rating displayed within reviews and best-of lists.
Driving speed
Our driving speed tests are critical in evaluating impact driver performance. While torque is also essential, driving screws and fasteners quickly saves time.
The data points included in our ratings in this category are as follows:
Driving speed total time: Our driving speed tests are designed to push impact drivers to their limits. We do so by driving five 5/16-inch, 5 1/8-inch long GRK structural screws into treated lumber in both forward and reverse and measuring the time to complete each task. We use the total driving time in the forward setting as an input in our rating methodology.
Read more about our impact driver driving speed testing methodology and review our impact driver driving speed test results for more information.
Max RPM: We don’t rely on advertised RPMs to inform our ratings. We test RPM in-house using a contact tachometer. We use the max RPM readout in the forward setting as an input in our rating methodology.
Read more about our impact driver RPM testing methodology and review our impact driver RPM test results for more information.
Torque
We test torque in our lab using a commercial-grade Inertia Tools L-1000 Torque Meter.
The data point included in our ratings in this category is as follows:
Max torque (in-lbs): We test the maximum torque of each impact driver in the high-speed drive setting.
Read more about our impact driver torque testing methodology and review our impact driver torque test results for more information.
Driving precision
While impact drivers are designed chiefly for heavy-duty tasks where precision isn’t as critical as speed or torque, there’s no denying the value of having a tool equally capable in light and medium-duty tasks where a precise screw recess and strong finish are essential.
The data point included in our ratings in this category is as follows:
Number of drive modes: We test each impact driver with various screw and fastener sizes driven into low and high-density materials, including hardwoods, dimensional lumber, plywood, MDF, and drywall. The higher the number of drive modes, the more precise an impact driver is. When testing, we also objectively pay attention to how accurately and consistently each impact driver finishes each screw type across our tested work materials.
Battery performance
Battery run time is a critical performance factor in evaluating impact drivers.
The data point included in our ratings in this category is as follows:
No-load battery run time: We test each impact driver’s battery run time in a no-load scenario using a 2Ah battery within each brand’s lineup.
Read more about our impact driver battery testing methodology and review our impact driver battery test results for more information.
Durability
Since we haven’t completed our long-term durability tests to understand longevity, we proxy the durability of an impact driver based on the length of the manufacturer’s warranty. Manufacturers that stand behind the longevity of their tools will offer long tool and battery warranties.
The data points included in our ratings in this category are as follows:
Tool warranty: The length of the manufacturer-provided warranty for the tool itself.
Battery warranty: The length of the manufacturer-provided warranty for the battery itself.
Convenience
The convenience category comprises data points that improve each impact driver’s versatility and ease of use.
The data points included in our ratings in this category are as follows:
Magnetic fastener holder: We assess whether each impact driver includes a magnetic plate onboard to hold fasteners.
Bit holder: We assess whether each impact driver includes a bit holder onboard to hold fasteners.
Easy-insert collet: We assess whether each impact driver includes an easy-insert collet design that requires only one hand to insert impact driver bits.
Bit-eject collet: We assess whether each impact driver includes a bit-eject collet design that jettisons bits when sliding back the collet, which is excellent for convenience and one-handed bit removal.
Work light on/off: We assess whether each impact driver includes the functionality to turn the work light on/off when pulling the trigger.
Portability/footprint
The portability/footprint category comprises data points from our lab test, all included with the goal of rating favorably the most compact, agile, and lightweight impact drivers in their class.
The data points included in our ratings in this category are as follows:
Bare tool weight: We test each impact driver’s bare tool weight on a commercial-grade scale.
Read more about our impact driver weight testing methodology and review our impact driver weight test results for more information.
Max height: We measure each impact driver’s bare tool max height using digital calipers to understand the interior spaces each model can fit into.
Read more about our impact driver footprint testing methodology and review our impact driver footprint test results for more information.
Collet-to-back length: We measure each impact driver’s measurement from tip to back using digital calipers to understand the tight corners and narrow spaces each model can fit into.
45-degree interior clearance: We dreamed up a test to understand in practical terms how the collet-to-back length affects the corners an impact driver can fit into. We measure the 45-degree interior clearance using a specialty box and measuring surface created in our lab.
Read more about our impact driver interior clearance testing methodology and review our impact driver interior clearance test results for more information.
Noise
While we measure each impact driver’s noise output in a no-load scenario and when impacting, we only include one readout in our rating methodology. In practice, the noise when impacting is essential, not how loud each model is when not driving screws.
Max noise when impacting: We test each impact driver’s noise output using a digital sound meter during our driving speed tests.
Read more about our impact driver noise testing methodology and review our impact driver noise test results for more information.
Weightings
Depending on the tool’s voltage, we apply different weightings to the eight categories to ensure the overall rating our model outputs correctly characterizes the intended usage for each class of impact drivers.
Our two weighting approaches are defined as our light and heavy-duty rating methodologies. In proximity to each impact driver’s editorial rating, we include the rating methodology applied so readers can understand how well an impact driver performs for its intended usage.
Light-duty methodology
Our light-duty methodology emphasizes precision, portability/footprint, battery performance, and driving speed. We adjust the category weightings per the below table to reflect this approach.
| Category | Weighting |
|---|---|
| Driving speed | 15.0% |
| Torque | 5.0% |
| Driving precision | 25.0% |
| Battery performance | 15.0% |
| Durability | 10.0% |
| Convenience | 5.0% |
| Portability/footprint | 20.0% |
| Noise | 5.0% |
Heavy-duty methodology
Our heavy-duty methodology emphasizes driving speed, torque, precision, and battery performance. We adjust the category weightings per the below table to reflect this approach.
| Category | Weighting |
|---|---|
| Driving speed | 35.0% |
| Torque | 20.0% |
| Driving precision | 15.0% |
| Battery performance | 15.0% |
| Durability | 9.0% |
| Convenience | 2.0% |
| Portability/footprint | 2.0% |
| Noise | 2.0% |
How price influences ratings
The short answer is that price doesn’t influence our numerical editorial rating. We don’t use a model to assess factors such as performance for the price. One goal with our ratings is understanding the best models available, regardless of cost. After reading our reviews, Readers can determine what impact driver fits their budget.
While we don’t include a price-to-performance metric in our methodology, it doesn’t mean picks on our best-of lists aren’t influenced by price. When two equally-performing impact drivers are candidates for a best-of list, we are biased toward including the lower-priced version.
