# MRO Shop Capacity and Backlog Weeks Calculator

> Source: https://netray.co/tools/mro-capacity-and-backlog-weeks-calculator
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Free Tools

## Short answer

Turns headcount, shifts, utilisation and standard hours per unit into weekly capacity and how many weeks the backlog will take.

## Category

aerospace-defense

## Industry

Aerospace MRO

## Audience

- MRO planner
- Shop manager
- Production controller

## Tool

**Kind:** calculator

**Currency:** $

**Inputs:**

#### Technicians per shift

**Key:** techs

**Type:** number

**Default:** 8

**Min:** 0

**Step:** 1

**Unit:** people

**Help:** Count only licensed or skilled staff who work on the units.

#### Paid hours per technician per day

**Key:** shift_hours

**Type:** number

**Default:** 8

**Min:** 0

**Step:** 0.5

**Unit:** hours

#### Shifts per day

**Key:** shifts

**Type:** select

**Default:** 1

**Options:**

##### 1 shift

**Value:** 1

##### 2 shifts

**Value:** 2

##### 3 shifts

**Value:** 3

#### Working days per week

**Key:** days

**Type:** number

**Default:** 5

**Min:** 1

**Max:** 7

**Step:** 1

**Unit:** days

#### Productive utilisation

**Key:** utilisation

**Type:** slider

**Default:** 70

**Min:** 30

**Max:** 95

**Step:** 1

**Unit:** %

**Help:** Share of paid hours charged to work orders. Typical shops range widely, use your own data.

#### Average standard hours per unit

**Key:** std_hours

**Type:** number

**Default:** 36

**Min:** 0.5

**Step:** 0.5

**Unit:** hours

#### Units in backlog

**Key:** backlog

**Type:** number

**Default:** 120

**Min:** 0

**Step:** 1

**Unit:** units

#### New units arriving per week

**Key:** inflow

**Type:** number

**Default:** 12

**Min:** 0

**Step:** 1

**Unit:** units

**Outputs:**

#### Productive hours per week

**Key:** weekly_hours

**Expr:** techs * shifts * shift_hours * days * utilisation / 100

**Format:** number

**Description:** Hours that can be charged to work orders each week.

#### Units completed per week

**Key:** units_per_week

**Expr:** weekly_hours / std_hours

**Format:** decimal

**Primary:** true

**Description:** Capacity expressed in units at the average standard time.

#### Net backlog reduction per week

**Key:** net_burn

**Expr:** units_per_week - inflow

**Format:** decimal

**Description:** Positive means the backlog shrinks, negative means it grows.

#### Weeks to clear backlog

**Key:** weeks_to_clear

**Expr:** if(gt(net_burn, 0), backlog / net_burn, 0)

**Format:** weeks

**Primary:** true

**Description:** Shown as 0 when inflow equals or exceeds capacity, because the backlog never clears.

#### Inflow as share of capacity

**Key:** load_pct

**Expr:** inflow / units_per_week * 100

**Format:** percent

**Description:** Above 100 percent means the shop is overloaded.

#### Extra technicians to match inflow

**Key:** extra_techs

**Expr:** max(0, ceil((inflow * std_hours) / (shifts * shift_hours * days * utilisation / 100)) - techs)

**Format:** integer

**Description:** Headcount per shift needed so that capacity equals new arrivals.

**Chart:**

#### Units per week vs technicians per shift

**Type:** line

**X:** techs

**From:** 1

**To:** 30

**Steps:** 30

**Series:**

- units_per_week

**Disclaimer:** A planning estimate using an average standard time. Real turn times depend on part availability, test equipment, skills mix and customer approval delays.

## Content

**Intro:** A shop with a growing backlog needs to know whether the problem is capacity, mix or waiting time. This calculator converts headcount, shifts, utilisation and standard hours into units per week and weeks of backlog.

**Sections:**

#### How to use the calculator

**Body:** Enter technicians per shift, paid hours per day, shifts, working days and your productive utilisation. Then add the average standard hours per unit, the current backlog and the average weekly arrivals. The results show productive hours per week, units completed per week, the net change in backlog each week and how many weeks it will take to clear. Use the slider to see how sensitive the answer is to utilisation, which is often the least understood input.

**Bullets:**

- Use utilisation from charged hours divided by paid hours
- Use an average standard time that reflects your real mix
- Enter arrivals as a typical week, not a peak

#### The formulas

**Body:** Productive hours per week equals technicians times shifts times paid hours times days times utilisation. Units per week is productive hours divided by average standard hours. Net burn is units per week minus weekly arrivals. If net burn is positive, weeks to clear equals backlog divided by net burn. If arrivals equal or exceed capacity, the backlog does not clear and the tool shows zero for weeks to clear, so check the load percentage and the extra technician estimate.

#### Worked example and cautions

**Body:** With eight technicians, one shift, eight hours, five days and 70 percent utilisation, productive hours are 224 per week. At 36 hours per unit that is about 6.2 units a week. If 12 units arrive each week, the shop is at roughly 193 percent of capacity and needs about eight more technicians per shift, or a lower standard time or higher utilisation, just to stand still. Averages hide mix: a few long overhauls can distort capacity, so run the tool separately for each unit family.

**Bullets:**

- Run it by product family
- Check standard times against actuals
- Remember that waiting for parts does not use labour hours

**Cta:** If you want capacity checked against live work orders and labour data in your ERP, we can build a read-only view that does this calculation automatically.

**Faq:**

#### What utilisation should I use?

**Answer:** Use your own figure: hours charged to work orders divided by paid hours over a representative period. It is lower than most people expect once training, meetings, waiting and rework are counted.

#### Why does the weeks to clear show zero?

**Answer:** The tool shows zero when new arrivals are equal to or higher than capacity, because the backlog would never clear. Check the load percentage and the extra technicians result to size the gap.

#### Should I use standard hours or actual hours?

**Answer:** Use actual average hours if standards are out of date. If actuals are much higher than standards, that is a finding in itself, and the standards, the estimating or the process should be reviewed.

#### Does this include waiting time for parts?

**Answer:** No. It only models labour capacity. A unit waiting for parts or approval still sits in the backlog but uses no hours, so total turn time can be much longer than the capacity calculation suggests.

## Search terms

mro capacity calculator, repair shop backlog weeks, maintenance shop capacity planning, technician hours capacity calculator, component repair backlog calculator, man hour capacity mro, shop load calculation

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