Dewalt 3 Free Tools Deal – Prorated Value Calculator

Retailers have a new Dewalt tool deal for the 2025 Black Friday and holiday shopping season.

With this deal, you buy a Dewalt 20V Max starter kit, with 2x PowerPack 8Ah tabless batteries and a fast charger, and you can choose 3 FREE cordless power tools or accessories from a group of options.

Acme Tools’ deal went live but (temporarily?) sold out.
Lowe’s deal is live.
Home Depot is expected to follow, possibly with their own PowerPack starter set.

Nothing is really “free,” you’re really just spreading the starter kit purchase price across a customized 3-tool combo kit. It can be daunting to figure out how much you’re paying for everything, and so we sought to simplify the math.

I coded a new calculator to help you quickly figure out the prorated value for (3) free items:

I previously made a calculator for one or two free bonus items, here: “Free Cordless Power Tool and Battery” Deal Value Calculator. You can use the calculator above for 1, 2, or 3 free items as well, just leave the other extra lines values blank.

I should add that this works for more than just Dewalt freebies, but so far I’ve only ever see Dewalt offer as many as 3 free bonus items, and rarely at that.

How the Math Works

I’ll go over the math in case you’re interested.

To put it simply, the prorated value of a “free” item is equal to item price minus item savings.

You need these numbers to start off with:

Pt = Price of the tool you have to buy
V1 = Value of the first bonus item you choose
V2 = Value of the second bonus item you choose
V3 = Value of the third bonus item you choose

The value of the free bonus item will usually look something like: $169 FREE.

Vall = the sum of the bonus values (V1 + V2 + V3)

Here’s another way to look at it. You’re spending an amount, Pt, for a collection of items valued at (Pt + V1 + V2 + V3), or (Pt + Vall). Pt is the price you spend to get Pt + V1 + V2 + V2.

Everything in this type of deal offer is discounted proportional to how much you spend for the pre-determined value that you get.

So we need the discount ratio, D.

D = Vall / (Pt + Vall). This is the discount ratio, the sum of the value of free items divided by the same figure plus what you’re spending out of pocket on the tool. It’s what you get for free, divided by the total value, including the “buy this” starter kit or other purchase.

Let’s say the discount ratio (D), is the value of what you get for free, divided by the total value of the purchase.

Discount = Freebies / tool plus freebies

Because the advertised savings could be completely fictitious, it can be helpful to consider what you’re spending on each individual item, if the discount is evenly applied across all items.

Let’s say you want to know the prorated value (PV) of any of the items, whether it’s the “buy this” tool or “get that for free” items.

PVt = Prorated cost or return value of the tool you have to buy
PV1 = Prorated cost or return value of the first bonus item you choose
PV2 = Prorated cost or return value of the second bonus item you choose
PV3 = Prorated cost or return value of the third bonus item you choose

Here’s how you calculate it out. Don’t get flustered, I’ll try to simplify things.

PVt = Vt – { (Vt x Vall) / (Pt + Vall) }
PV1 = V1 – { (V1 x Vall) / (Pt + Vall) }
PV2 = V2 – { (V2 x Vall) / (Pt + Vall) }
PV3 = V3 – { (V3 x Vall) / (Pt + Vall) }

Pt = PVt + PV1 + PV2 + PV3 ; this is the price you pay for everything, including the “buy this” tool and “get 3 free tools” items. The sum of the prorated valued should always equal the amount paid.

For ANY item in such an order, with value Pi, the prorated value is PVi = Pi – (Pi x D).

Or, PVi = Pi – (Pi x Vall) / (Pt + Vall). You need to do this for EACH item.

Example: If you buy a drill for $100, and get a $10 set of drill bits for free, the effective discount (D) would be $10 / $110, or ~9.1%, since you’re spending $100 for $110 worth of stuff.

There are other ways to do the math, but this way worked out easiest for me: Prorated item value = Item price – Item savings

I hope you can appreciate why I figured out the math and then worked to build an easy to use calculator.

Let’s work through a hypothetical example.

You pay (Pt): $400 for a starter get
Free tool1 (V1): $50 battery
Free tool2 (V2): $150 impact driver
Free tool3 (V3): $200 rotary hammer

Vall, the sum of all the freebie items, is $400.

Discount Ratio = Vall / (Pt + Vall) -> $400 / $800 – 50%

Does that make sense? In this hypothetical, you’re getting an effective discount of 50%.

Prorated Value = Price – (Price x Discount)

Prorated value of the tool = $400 – ($400 x 0.5) = $200
Prorated value of the first free tool = $50- ($50 x 0.5) = $25
Prorated value of the second free tool = $150 – ($150 x 0.5) = $75
Prorated value of the third free tool = $200 – ($200 x 0.5) = $100

Add it all up, and $200 + $25 + $75 + $100 = the $400 that you paid for the starter kit. $400 for $800 worth of gear would apply a 50% discount across all items for the prorated value.

Let’s say that the impact driver is faulty. If you’re able to return or exchange it, the prorated cost would be used to determine its return value, or $75 in this example.

Let’s say the starter kit is $449, and free tool items are assigned values of $109, $127, and $142. How much are you really paying for the $127 item?

PV = $127 – { ($127 x ($109 + $127 + $142)) / ($449 + $109 + $127 + 142) }

That would be… $127 – { ($127 x $378) / (827) } -> $127 – $58.05 = $68.95

Or just enter the numbers (449, 109, 127, 142), and you get to the same number. It’ll spit out all 4 numbers faster than you can open the calculator app on your phone.

Questions?