# Make to Order Promise Date and Lead Time Calculator

> Source: https://netray.co/tools/make-to-order-promise-date-lead-time-calculator
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Free Tools

## Short answer

Compute the calendar days to promise a customer from material arrival, queue, setup, run hours at your efficiency, and ship time.

## Category

manufacturing

## Audience

- Planner
- Production manager
- Sales

## Tool

**Kind:** calculator

**Inputs:**

#### Order quantity

**Key:** qty

**Type:** number

**Default:** 120

**Min:** 1

**Step:** 10

**Unit:** units

#### Setup time per run

**Key:** setup_min

**Type:** number

**Default:** 90

**Min:** 0

**Step:** 5

**Unit:** min

#### Run time per unit

**Key:** run_min

**Type:** number

**Default:** 6

**Min:** 0

**Step:** 0.5

**Unit:** min

#### Line efficiency

**Key:** efficiency

**Type:** slider

**Default:** 80

**Min:** 30

**Max:** 100

**Step:** 1

**Unit:** %

**Help:** Actual output versus standard, including minor stops.

#### Productive hours per working day

**Key:** hours_day

**Type:** number

**Default:** 7.5

**Min:** 1

**Max:** 24

**Step:** 0.5

**Unit:** hrs

#### Queue wait before start

**Key:** queue_days

**Type:** number

**Default:** 3

**Min:** 0

**Step:** 1

**Unit:** working days

#### Material lead time

**Key:** material_days

**Type:** number

**Default:** 10

**Min:** 0

**Step:** 1

**Unit:** working days

**Help:** Zero if material is in stock.

#### Packing and transit

**Key:** ship_days

**Type:** number

**Default:** 2

**Min:** 0

**Step:** 1

**Unit:** working days

#### Working days per week

**Key:** week_days

**Type:** select

**Default:** 5

**Options:**

##### 5 days

**Value:** 5

##### 6 days

**Value:** 6

##### 7 days

**Value:** 7

**Outputs:**

#### Machine hours needed

**Key:** run_hours

**Expr:** (setup_min + qty * run_min) / 60 / (efficiency / 100)

**Format:** hours

#### Production working days

**Key:** prod_days

**Expr:** run_hours / hours_day

**Format:** decimal

#### Total working days to ship

**Key:** work_days

**Expr:** material_days + queue_days + prod_days + ship_days

**Format:** decimal

#### Calendar days to promise

**Key:** cal_days

**Expr:** ceil(work_days * 7 / week_days)

**Format:** days

**Primary:** true

#### Promise in weeks

**Key:** weeks

**Expr:** cal_days / 7

**Format:** weeks

**Chart:**

#### Calendar days to promise vs order quantity

**Type:** line

**X:** qty

**From:** 10

**To:** 1500

**Steps:** 30

**Series:**

- cal_days

**Disclaimer:** Assumes one operation and sequential material, queue, production and shipping. Multi operation routings need each step summed.

## Content

**Intro:** Sales needs a delivery date today, and planners need it to be honest. This calculator adds the time stages of a make to order job into one defensible promise.

**Sections:**

#### How to use it

**Body:** Enter the quantity and the routing time per unit. Divide standard time by efficiency, because plants rarely hit 100 percent. Add queue time for work ahead of the job, material lead time if parts must be bought and the transit allowance. Choose how many days per week the plant runs so that working days convert into calendar days correctly.

#### Formula

**Body:** Machine hours equal setup plus quantity times run time, divided by 60 and by efficiency. Production days divide those hours by productive hours per day. Total working days sum material, queue, production and shipping. Calendar days multiply by seven over working days per week and round up, so a five day plant turns ten working days into fourteen calendar days.

**Bullets:**

- Setup is paid once per run, not per unit
- Efficiency below 100 percent stretches run hours
- Shorter material lead time is usually the biggest lever
- Queue should reflect real backlog, not hope

#### Reading the chart

**Body:** At low quantities the line is flat because material, queue and shipping dominate. At high quantities run time takes over and the line climbs. The kink shows the quantity where quoting a longer date is unavoidable. Use it to set standard lead time bands for sales.

#### Common mistakes

**Body:** Teams quote from standard time without efficiency, forget that material and production can overlap only if you receive partial shipments, and ignore queue. If you overlap steps, reduce the relevant days manually. For multi step routings, run each operation and sum the production days.

**Cta:** If your ERP holds routings and open orders, Netray can help you calculate promise dates directly from that data.

**Faq:**

#### What efficiency should I use?

**Answer:** Use your measured OEE-style output versus standard over the last quarter. Many small plants run 65 to 85 percent. Using 100 percent will produce dates you cannot keep.

#### How do I handle multiple operations?

**Answer:** Run the calculator for each operation and add the production days, plus queue between operations. Alternatively sum all setup and run times into one total as an approximation.

#### Why are calendar days larger than working days?

**Answer:** Weekends and non working days pass while the job waits. A five day plant needs seven calendar days for every five working days, so the conversion factor is seven divided by five.

#### Can material and production overlap?

**Answer:** Yes if you can start with partial material. In that case lower the material days to the portion that blocks the first operation, or accept the sequential figure as a conservative promise.

## Search terms

make to order lead time calculator, promise date calculator manufacturing, production lead time formula, order lead time estimate, capable to promise small manufacturer, manufacturing lead time calculator, job shop lead time

---
Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json