# Returnable Rack Pool Size Calculator

> Source: https://netray.co/tools/returnable-rack-pool-size-calculator
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Free Tools

## Short answer

Estimate how many returnable racks or containers a customer loop needs, from daily demand, parts per rack and total loop time.

## Category

supply-chain

## Industry

Automotive

## Audience

- Logistics engineer
- Packaging engineer
- Supply chain planner

## Tool

**Kind:** calculator

**Currency:** $

**Inputs:**

#### Daily customer demand

**Key:** daily_demand

**Type:** number

**Default:** 1800

**Min:** 0

**Step:** 50

**Unit:** parts per day

**Help:** Average parts shipped per working day.

#### Parts per rack

**Key:** parts_per_rack

**Type:** number

**Default:** 60

**Min:** 1

**Step:** 1

**Unit:** parts

**Help:** Standard pack quantity.

#### Supplier fill and staging time

**Key:** supplier_time

**Type:** number

**Default:** 2

**Min:** 0

**Step:** 0.5

**Unit:** days

#### Transit to customer

**Key:** transit_out

**Type:** number

**Default:** 2

**Min:** 0

**Step:** 0.5

**Unit:** days

#### Customer dwell before emptying

**Key:** customer_dwell

**Type:** slider

**Default:** 3

**Min:** 0

**Max:** 14

**Step:** 0.5

**Unit:** days

#### Return transit and washing

**Key:** transit_back

**Type:** number

**Default:** 3

**Min:** 0

**Step:** 0.5

**Unit:** days

#### Safety allowance

**Key:** safety

**Type:** slider

**Default:** 20

**Min:** 0

**Max:** 100

**Step:** 5

**Unit:** %

#### Annual loss and damage allowance

**Key:** loss

**Type:** number

**Default:** 5

**Min:** 0

**Step:** 1

**Unit:** %

#### Cost per rack

**Key:** rack_cost

**Type:** number

**Default:** 320

**Min:** 0

**Step:** 10

**Unit:** $

**Outputs:**

#### Total loop time

**Key:** loop

**Expr:** supplier_time + transit_out + customer_dwell + transit_back

**Format:** days

**Description:** Days one rack is out of circulation from fill to refill.

#### Racks consumed per day

**Key:** racks_day

**Expr:** daily_demand / parts_per_rack

**Format:** decimal

#### Racks in loop before allowances

**Key:** base

**Expr:** racks_day * loop

**Format:** integer

#### Recommended pool size

**Key:** pool

**Expr:** ceil(racks_day * loop * (1 + safety / 100) * (1 + loss / 100))

**Format:** integer

**Primary:** true

**Description:** Rounded up, includes safety and loss allowance.

#### Capital invested in racks

**Key:** capital

**Expr:** pool * rack_cost

**Format:** currency

**Primary:** true

**Chart:**

#### Pool size vs customer dwell time

**Type:** line

**X:** customer_dwell

**From:** 0

**To:** 14

**Steps:** 15

**Series:**

- pool

**Disclaimer:** Planning estimate. Final pool sizing should reflect customer agreed pack specifications, seasonal peaks, shutdown calendars and trial data.

## Content

**Intro:** A returnable rack loop ties up capital in packaging that is not in your product. Too few racks stops shipments, too many wastes cash and floor space. This calculator sizes the pool from demand and the time a rack spends in the loop.

**Sections:**

#### How the calculation works

**Body:** Racks needed per day equal daily demand divided by parts per rack. Each rack is out of circulation for the full loop time, which is fill and staging, transit to the customer, customer dwell and return transit with cleaning. The base pool is racks per day multiplied by loop days. The calculator then applies a safety allowance for variability and a loss allowance for damage and shrinkage and rounds up.

#### Worked example

**Body:** At 1,800 parts per day and 60 parts per rack, the loop consumes 30 racks per day. With a 10 day loop the base pool is 300 racks. A 20 percent safety allowance and a 5 percent loss allowance bring the recommendation to 378 racks. At 320 dollars per rack that is about 121,000 dollars of capital. The chart shows that each extra day of customer dwell adds about 38 racks.

#### Where the time hides

**Body:** Customer dwell and return transit are usually the largest and least controlled parts of the loop. Measure them with real tracking rather than assumptions. Sharing the chart with the customer is a good way to agree a maximum dwell time, since it translates days into dollars.

**Bullets:**

- Check the customer line side stock level policy
- Include cleaning and repair time in the return leg
- Allow for holiday shutdowns and weekends in the loop days
- Review pool size after each demand change

#### Common mistakes

**Body:** Using calendar days where demand is in working days overstates the base pool. Ignoring partial racks understates the pool, so round up. Failing to include loss means the pool shrinks every year. Finally, many programs forget that a rack design change or a pack quantity change resets the calculation. In an ERP, returnable containers may be tracked as inventory or as assets with a custody location.

**Cta:** If rack movements are recorded in your ERP or a tracking system, Netray can analyze actual loop times and pool balances. The calculator works without that data.

**Faq:**

#### How many returnable racks do I need?

**Answer:** Multiply racks consumed per day by total loop days, then add allowances for variability and loss. The calculator performs that and rounds up to a whole rack.

#### What safety allowance is typical?

**Answer:** It depends on variability of transit and customer emptying. Ten to thirty percent is a common planning range. Use measured loop time spread rather than a rule of thumb where you can.

#### Should I use working days or calendar days?

**Answer:** Be consistent. If demand is per working day, loop time should also be counted in working days, or convert demand to calendar days. Mixing the two causes errors.

#### Does the cost include maintenance and cleaning?

**Answer:** No. Capital is rack count times unit cost. Add washing, repair, tracking and freight for the return leg to get the total cost of the returnable system.

## Search terms

returnable container pool size calculator, returnable rack quantity calculation, returnable packaging pool sizing, kanban container quantity, rack loop time calculator, returnable packaging cost calculator, automotive returnable packaging

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