How do you calculate average work-order age?

Sum the age (in days) of every open work order to get total open order-days, divide by the open order count, then apply any calendar adjustment factor. With 1,260 order-days across 84 orders at a 1x factor, the average age is 15 days.

What is the calendar adjustment factor for?

It converts calendar days to working days, or applies a shop-specific weighting. A factor of 1 leaves the raw average unchanged; use something like 5/7 to express age in working days only.

What is a good average work-order age?

It depends on your typical job lead time — age should track close to your standard throughput time. If your jobs normally clear in 7-10 days, a 15-day average like the example suggests orders are backing up.

Why track average age instead of just past-due orders?

Past-due is a lagging signal. Average age rises before orders breach their due dates, giving you a lead indicator of WIP buildup so you can react before shipments slip.

How is total open work-order age measured?

For each open order, count the days since it was released or opened, then sum across all open orders. That total in order-days is the numerator before dividing by order count.

Can a low average age still hide a problem?

Yes. A handful of orders aging 60+ days can be diluted by many new releases. Always review the aging buckets alongside the average to catch stuck outliers.

ERP & MRP Planning calculator

Work Order Aging Calculator

Work-order aging measures how long your open work orders have been sitting in the system on average, in days. Production control, MRP planners, and shop-floor supervisors use it to gauge WIP backlog and catch orders stalling on the floor. By dividing total open order-days by the number of open orders, it turns a messy pile of WIP into one clear age number you can trend and benchmark. A creeping average is an early warning that orders are starting and not finishing — a classic symptom of material shortages, bottlenecks, or releasing more work than the floor can absorb.

What this calculator does

Estimate average open work-order age from total aged order-days and open work-order count.
a production planner needs to summarize how old open work orders are
It computes the average age of open work orders by dividing total accumulated open order-days by the open order count, scaled by a calendar factor.

Formula used

Average work-order age = total open work-order age ÷ open work-order count × calendar adjustment factor

Inputs explained

Total open work-order age:
Open work-order count:
Calendar adjustment factor:

How to use the result

Use it weekly or daily to monitor WIP health and flag aging orders before they become past-due.
An average hides outliers — a few very old orders can be masked by many fresh ones, so pair it with an aging distribution.

Current U.S. benchmarks

Manufacturing hourly earnings average $30.27 (BLS, Jun 2026), up 4.4% from a year earlier. Median machinist pay is $28.24/hr (OEWS 2025), with state medians on each state page. Manufacturers have 529k open positions nationally (BLS JOLTS).
U.S. manufacturing runs at 75.6% of capacity (Federal Reserve, May 2026). New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate average work-order age? Sum the age (in days) of every open work order to get total open order-days, divide by the open order count, then apply any calendar adjustment factor. With 1,260 order-days across 84 orders at a 1x factor, the average age is 15 days.
What is the calendar adjustment factor for? It converts calendar days to working days, or applies a shop-specific weighting. A factor of 1 leaves the raw average unchanged; use something like 5/7 to express age in working days only.
What is a good average work-order age? It depends on your typical job lead time — age should track close to your standard throughput time. If your jobs normally clear in 7-10 days, a 15-day average like the example suggests orders are backing up.
Why track average age instead of just past-due orders? Past-due is a lagging signal. Average age rises before orders breach their due dates, giving you a lead indicator of WIP buildup so you can react before shipments slip.
How is total open work-order age measured? For each open order, count the days since it was released or opened, then sum across all open orders. That total in order-days is the numerator before dividing by order count.

Last reviewed 2026-05-12.