# CNC Material Blank Cost Calculator

> Source: https://netray.co/tools/cnc-material-blank-cost-calculator
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Free Tools

## Short answer

Size the blank from the finished part and stock allowance, then cost it from bar length, saw kerf, end drop and chip scrap credit.

## Category

supply-chain

## Industry

CNC Machining

## Audience

- Estimator
- Buyer
- Manufacturing engineer

## Tool

**Kind:** calculator

**Currency:** $

**Inputs:**

#### Stock shape

**Key:** shape

**Type:** select

**Default:** 1

**Options:**

##### Rectangular bar or plate

**Value:** 1

##### Round bar

**Value:** 2

**Help:** For round bar, width is the diameter and thickness is ignored.

#### Finished length

**Key:** fin_l

**Type:** number

**Default:** 6

**Min:** 0

**Step:** 0.125

**Unit:** in

#### Finished width or diameter

**Key:** fin_w

**Type:** number

**Default:** 3

**Min:** 0

**Step:** 0.125

**Unit:** in

#### Finished thickness

**Key:** fin_t

**Type:** number

**Default:** 1

**Min:** 0

**Step:** 0.125

**Unit:** in

#### Stock allowance per dimension

**Key:** allow

**Type:** number

**Default:** 0.125

**Min:** 0

**Step:** 0.0625

**Unit:** in

**Help:** Added to length, width and thickness for facing and cleanup. Typical 0.0625 to 0.25.

#### Material

**Key:** density

**Type:** select

**Default:** 0.0975

**Options:**

##### Aluminum 6061 (0.0975 lb/in3)

**Value:** 0.0975

##### Steel 4140 (0.284 lb/in3)

**Value:** 0.284

##### Stainless 304 (0.289 lb/in3)

**Value:** 0.289

##### Brass C360 (0.307 lb/in3)

**Value:** 0.307

##### Titanium Ti-6Al-4V (0.160 lb/in3)

**Value:** 0.16

#### Material price

**Key:** price

**Type:** number

**Default:** 4.2

**Min:** 0

**Step:** 0.1

**Unit:** $/lb

**Help:** Delivered price per pound from your supplier quote.

#### Saw kerf

**Key:** kerf

**Type:** number

**Default:** 0.125

**Min:** 0

**Step:** 0.0125

**Unit:** in

#### Purchased bar length

**Key:** bar_len

**Type:** number

**Default:** 144

**Min:** 1

**Step:** 12

**Unit:** in

#### Unusable end drop

**Key:** end_drop

**Type:** number

**Default:** 2

**Min:** 0

**Step:** 0.5

**Unit:** in

**Help:** Length lost for gripping, end defects and the final remnant.

#### Chip scrap value

**Key:** scrap_val

**Type:** number

**Default:** 0.6

**Min:** 0

**Step:** 0.05

**Unit:** $/lb

**Outputs:**

#### Blank length

**Key:** bl

**Expr:** fin_l + allow

**Format:** decimal

#### Blank width or diameter

**Key:** bw

**Expr:** fin_w + allow

**Format:** decimal

#### Blank thickness

**Key:** bt

**Expr:** fin_t + allow

**Format:** decimal

#### Blank weight

**Key:** blank_wt

**Expr:** if(eq(shape, 1), bl * bw * bt, pi / 4 * bw * bw * bl) * density

**Format:** decimal

**Description:** Pounds per blank from volume x density.

#### Finished part weight

**Key:** fin_wt

**Expr:** if(eq(shape, 1), fin_l * fin_w * fin_t, pi / 4 * fin_w * fin_w * fin_l) * density

**Format:** decimal

#### Parts per purchased bar

**Key:** ppb

**Expr:** floor((bar_len - end_drop + kerf) / (bl + kerf))

**Format:** integer

**Description:** n x blank + (n - 1) x kerf must fit in the usable length.

#### Bar weight charged per part

**Key:** bar_wt_pp

**Expr:** if(eq(shape, 1), bw * bt, pi / 4 * bw * bw) * bar_len * density / ppb

**Format:** decimal

**Description:** Includes kerf and end drop.

#### Material cost per part from bar

**Key:** bar_cost_pp

**Expr:** bar_wt_pp * price

**Format:** currency

#### Chip scrap credit per part

**Key:** credit

**Expr:** (blank_wt - fin_wt) * scrap_val

**Format:** currency

#### Net material cost per part

**Key:** net_cost

**Expr:** bar_cost_pp - credit

**Format:** currency

**Primary:** true

#### Material utilization

**Key:** yield_pct

**Expr:** fin_wt / bar_wt_pp * 100

**Format:** percent

**Primary:** true

**Description:** Finished weight as a share of weight purchased for this part.

**Chart:**

#### Net material cost per part vs stock allowance

**Type:** line

**X:** allow

**From:** 0

**To:** 0.5

**Steps:** 25

**Series:**

- net_cost
- bar_cost_pp

**Disclaimer:** Densities are typical handbook values and vary by alloy and temper. Use mill certificate weights or supplier published weights for final pricing. Does not include cutting fees, minimum order charges or freight.

## Content

**Intro:** Material is often 20 to 50 percent of a machined part's cost, and it is the easiest part of a quote to get slightly wrong in a way that adds up. This calculator sizes the blank, then charges the part for kerf, end drop and the bar it actually consumes.

**Sections:**

#### How to use the calculator

**Body:** Pick the stock shape and enter the finished length, width (or diameter) and thickness. Add a stock allowance per dimension for facing and cleanup. Choose the material to load its handbook density, then enter the delivered price per pound. For saw-cut bar, enter the kerf, the purchased bar length and the unusable end drop. The result is parts per bar, the bar weight charged to each part, a credit for recoverable chips and the net material cost per part. The chart shows how sensitive net cost is to the allowance you choose.

**Bullets:**

- Use delivered price, including freight and cut charges where applicable
- Round blank dimensions up to the next available stock size before costing
- For plate, enter the nest-able cut size rather than the full plate

#### Formulas and assumptions

**Body:** Blank weight = volume x density. Rectangular volume is length x width x thickness, and round volume is pi/4 x diameter squared x length. Parts per bar is floor((usable length + kerf) / (blank length + kerf)), because n blanks need n x blank length plus (n - 1) kerf cuts. Bar weight per part is the full cross-section times purchased length times density, divided by parts per bar, which charges each part its share of the end drop and remnant. The scrap credit is the removed weight times your chip value. Densities used are common handbook values, for example 0.0975 lb/in3 for 6061 aluminum and 0.284 lb/in3 for 4140 steel.

#### Reading utilization

**Body:** Utilization is finished weight over purchased weight for the part. A 6 x 3 x 1 in aluminum part in 3.125 x 1.125 in bar might show roughly 50 to 60 percent utilization, which is not unusual for pocketed parts and is exactly why buy-to-fly ratios matter. If utilization is low, consider whether near-net stock, a different bar section or nesting two parts across the width would help. The chart shows that every extra 0.0625 in of allowance costs real money on a high-volume part, so confirm the minimum allowance your process and supplier tolerances require.

#### Common mistakes

**Body:** Quoting from finished weight and a flat scrap factor hides the effect of kerf and drop on short parts, where kerf can be several percent. Another error is using theoretical density for plate with mill tolerance overrun, which can add a few percent of weight. Estimators also forget minimum buy quantities: a lot of 12 parts still pays for a whole bar unless you have stock. Treat leftover bar as inventory only if you have a realistic chance of using it.

**Cta:** If your material prices and bar yields sit in ERP purchase history, Netray can feed current cost per pound and remnant data into quotes automatically.

**Faq:**

#### What stock allowance should I use?

**Answer:** A typical allowance is 0.0625 to 0.125 inches per face for mill finish bar and plate, and more for hot rolled, forged or heavily bowed stock. Check with your supplier on flatness and straightness tolerances.

#### Why does the calculator charge for the end drop?

**Answer:** Because you pay for the full bar. Spreading unusable end length and the final remnant across parts that come from the bar is the honest way to cost material for a given lot.

#### Is chip scrap credit realistic?

**Answer:** It can be, but only if you segregate alloys and sell chips. If you do not, set the scrap value to zero. Contaminated mixed chips are worth little and sometimes cost money to dispose of.

#### Does it handle tubing or castings?

**Answer:** Not directly. For tubing enter an equivalent solid volume through the dimensions you can use, or calculate weight from supplier pounds per foot. For castings, use the casting weight and price per pound instead of a bar calculation.

## Search terms

cnc material cost calculator, blank size calculator machining, bar stock cost per part, material weight calculator aluminum steel, saw kerf bar stock yield, machined part material cost estimate, stock allowance machining, raw material cost per machined part

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