How do you calculate job lot cost?

Multiply units or openings by the burdened cost per unit and the scope percent, then add fixed project, freight, and setup cost. For 310 units at $246 each at 100% plus $9,800 fixed, the total is $86,060.

What is the job lot cost per unit in the example?

Total cost of $86,060 across 310 units is $277.61 per opening. That's above the $246 burdened rate because the $9,800 fixed project cost is amortized across every opening.

What should the burdened cost per unit include?

Material, direct labor, factory overhead, and any per-unit consumables — everything that scales with one more opening. The $246 default reflects a mid-range window or door unit fully loaded at the factory.

Why separate fixed project cost from per-unit cost?

Fixed cost doesn't shrink as the lot grows, so on small jobs it dominates the per-opening number. Keeping it separate lets you see that a 50-opening job carries far more fixed cost per opening than a 310-opening one.

How does job size change cost per opening?

Larger lots spread fixed cost thinner. The same $9,800 over 620 units instead of 310 would drop the per-opening cost from $277.61 toward $261.81, which is why volume jobs can be bid more aggressively.

Job lot cost vs unit cost — which do I quote from?

Quote from job lot cost, then divide for a per-opening number if the customer wants it. Quoting from the bare unit cost alone ignores freight and project management and erodes margin on every job.

Construction Products, Windows, Doors & Fenestration calculator

Job Lot Cost Calculator

Job lot cost is the all-in cost of a single window-and-door project order — every opening multiplied by its burdened per-unit cost, plus the fixed project-level cost of management, freight, and jobsite setup. Estimators and project managers at fenestration manufacturers and dealers use it to build accurate bids on commercial and multi-family jobs where a few hundred openings ship as one lot. This calculator separates the scalable per-opening cost from the fixed overhead that hits every project regardless of size, so you can see your true cost-per-opening before adding margin. It matters because under-counting fixed project cost is the fastest way to win a job and lose money on it.

What this calculator does

Estimate total job lot cost for a mixed construction-products order from unit count, lot cost per unit, scope, and fixed project adders.
building a quote cost basis for a project or dealer job lot
It computes total job lot cost from units times a burdened per-unit cost times captured scope, plus fixed project management, freight, and setup cost.

Formula used

Variable job lot cost = job lot units or openings × burdened job lot cost per unit × job lot cost scope included
Total job lot cost = variable job lot cost + fixed project management, freight, and setup cost

Inputs explained

Job lot units or openings:
Burdened cost per unit or opening:
Share of cost included in this job lot:
Fixed project management, freight, and jobsite setup cost:

How to use the result

Use it when estimating a project bid, validating a quote, or analyzing actual cost against estimate after a job closes.
A single burdened per-unit rate assumes a uniform product mix; jobs with a wide spread of window sizes and types need either a weighted rate or separate lines per product.

Current U.S. benchmarks

U.S. housing starts run at 1,177k per year (Census, May 2026), down 8.7% from a year earlier, the demand driver for building products.

Common questions

How do you calculate job lot cost? Multiply units or openings by the burdened cost per unit and the scope percent, then add fixed project, freight, and setup cost. For 310 units at $246 each at 100% plus $9,800 fixed, the total is $86,060.
What is the job lot cost per unit in the example? Total cost of $86,060 across 310 units is $277.61 per opening. That's above the $246 burdened rate because the $9,800 fixed project cost is amortized across every opening.
What should the burdened cost per unit include? Material, direct labor, factory overhead, and any per-unit consumables — everything that scales with one more opening. The $246 default reflects a mid-range window or door unit fully loaded at the factory.
Why separate fixed project cost from per-unit cost? Fixed cost doesn't shrink as the lot grows, so on small jobs it dominates the per-opening number. Keeping it separate lets you see that a 50-opening job carries far more fixed cost per opening than a 310-opening one.
How does job size change cost per opening? Larger lots spread fixed cost thinner. The same $9,800 over 620 units instead of 310 would drop the per-opening cost from $277.61 toward $261.81, which is why volume jobs can be bid more aggressively.

Last reviewed 2026-05-12.