Detailed Guide on Cost of Production

What Cost of Production Really Means

Cost of production is everything a manufacturer spends to turn raw materials into finished goods during a period: materials, the people who work on the product, and the factory overhead that keeps the lines running. Most finance teams can produce that total. The harder question, and the one that drives pricing, is what a single unit cost. Not the factory average, but one door, one bag, one panel, with its share of steel, labor hours, machine time, power, supervision and quality checks.

A plant that only knows its overall margin can be profitable in aggregate while losing money on a third of its catalogue. The winners quietly subsidize the losers, and decisions about pricing, discounts and which products to push are made on numbers that do not describe reality.

This guide breaks cost of production into its components, builds a complete worked example for a hypothetical steel door plant, compares the main costing methods, walks through variance analysis, and explains how an ERP system pulls purchasing, inventory, production and payroll data into one consistent cost.

Why So Many Plants Get Their Costs Wrong

The causes repeat from one factory to the next:

• Stale material prices. Costs are built on last year's price or the last invoice, while steel, polymer and aluminum prices move from shipment to shipment.
• Paper scrap rates. The cost sheet assumes 3% waste because someone typed it years ago. The old line actually scraps twice that.
• Overhead spread by units. Power, maintenance and supervision are divided by total units, so the simple high-volume product carries part of the cost of the complex low-volume one.
• Labor not tied to jobs. Wages hit the ledger as one monthly figure, and nobody knows how many hours went into each product.
• Invisible costs. Changeover time, rework on rejected batches and waiting between stations are real costs that never appear on their own line.

The root problem is rarely a lack of accounting knowledge. It is fragmented data. Purchasing knows prices, the storekeeper knows issues, the supervisor knows hours, and the accountant knows the totals. Nobody holds the whole picture.

The Three Building Blocks

Direct materials

Materials that become part of the product and can be measured per unit: steel sheet in a door, polyethylene granules in a bag, flour in a bakery. Getting them right requires:

• Landed cost: purchase price plus freight, insurance, non-recoverable customs duty and clearance. Saudi VAT at 15% stays out of cost when the company is registered and recovers input tax.
• Standard quantity: how many kilograms, meters or pieces one unit consumes, taken from an up-to-date bill of materials, not from a supervisor's memory.
• Expected scrap: cutting losses, trimming and the first pieces of every batch while the machine is set.
• Inventory cost formula: under IAS 2, as applied in the Kingdom, materials are measured using FIFO or weighted average. LIFO is not permitted.

Direct labor

The wages of people who work directly on the product: machine operators, welders, assemblers, packers. The common error is to use basic salary alone. A real labor hour includes:

• Basic salary, housing, transport and other fixed allowances.
• The employer's GOSI share: 11.75% of basic plus housing for Saudi employees under the existing system, and 2% occupational hazards for non-Saudis.
• Medical insurance, iqama and work permit costs for expatriate staff, spread across the year.
• End-of-service and paid annual leave provisions.
• Overtime linked to specific orders, paid under the Labor Law at the hourly wage plus 50% of the basic wage.

Divide that total by productive hours, not attendance hours. A worker who is on site 208 hours a month may spend 170 of them on production orders once breaks, meetings, training and waiting for material are taken out.

Manufacturing overhead

The driver you pick matters. If power is spread by units while one line draws three times as much as the others, every product cost in the plant is wrong, some too high and some too low.

A Full Worked Example: One Steel Door

Take a hypothetical plant in an industrial city that makes steel doors, with a normal capacity of 2,000 doors a month. The figures are illustrative.

Materials per door

• Net steel weight 38 kg with a 5% standard scrap allowance gives a standard quantity of 40 kg at SAR 4.20 per kg: SAR 168.
• Hinges, lock, paint and fixings: SAR 62.
• Packaging: SAR 10.
• Total materials: SAR 240.

Labor

Each door needs 1.5 hours across cutting, welding, assembly and painting. At a fully loaded productive rate of SAR 40 an hour, labor is SAR 60.

Overhead

Machine-related costs per month are depreciation SAR 60,000, energy SAR 45,000 and maintenance SAR 15,000, so SAR 120,000. Normal capacity is 1,000 machine hours, giving a rate of SAR 120 per machine hour. A door uses half a machine hour: SAR 60.

General factory overhead (supervision, quality, rent) of SAR 60,000 a month is spread over 3,000 direct labor hours, SAR 20 an hour, so each door carries 1.5 × 20 = SAR 30. Total overhead: SAR 90.

At a selling price of SAR 480, gross margin is SAR 90 per door, or 18.75%. That number becomes the anchor for every pricing and discount conversation.

What happens in a slow month

Suppose the plant makes only 1,400 doors and uses 700 machine hours instead of 1,000. The SAR 120,000 of fixed machine cost did not shrink. Should each door now carry SAR 171 instead of SAR 60? IAS 2 says no. Fixed production overhead is allocated on normal capacity, and the amount per unit is not increased because output is low or the plant is idle. The rate stays at SAR 120, and the 300 unused hours × 120 = SAR 36,000 are expensed in the period. Inventory is not inflated in weak months, and management sees the cost of idle capacity as its own figure.

Costing Methods and When Each Fits

Standard costing

Set a predetermined cost per product, as above, and compare it with actual results each period. It is the default for repetitive production because it supports quick quoting and exposes variances. It only works if standards are refreshed, at least quarterly for volatile materials.

Job costing

Costs are collected per production order or project. It suits make-to-order shops such as structural steel or custom joinery, where no two orders are alike.

Process costing

Costs are collected per stage (mixing, forming, filling) and divided by output, with work in progress converted to equivalent units. It fits continuous production such as cement, food and chemicals.

Activity-based costing

Overhead is traced to the activities that cause it, such as setups or inspections. A hypothetical case: product A runs 1,000 units a month with 2 setups, product B runs 50 units with 20 setups. Setup cost is SAR 44,000, or SAR 2,000 per setup.

On a units basis, product B looks fine. On a setup basis, it may well be sold below cost. Many plants run this analysis alongside the books rather than replacing standard costing.

Marginal costing

Variable and fixed costs are separated. If the door's variable cost is SAR 315 (materials 240, labor 60, variable energy 15) and a customer offers SAR 340 for 300 extra doors in a month with spare capacity, the order contributes SAR 25 a door, SAR 7,500 in total, toward fixed costs, even though SAR 340 is below the SAR 390 full cost. That is a defensible short-term decision, not a basis for list prices.

Variance Analysis: Where Did the Money Go?

A standard is only useful when compared with actuals. Back to the door plant in a month that produced 2,000 doors.

Material variances

Standard: 80,000 kg at SAR 4.20 = SAR 336,000. Actual: 83,000 kg at SAR 4.35 = SAR 361,050. The SAR 25,050 adverse gap splits into:

• Price variance: (4.35 − 4.20) × 83,000 = SAR 12,450. A question for purchasing: did the market move, did we buy from a pricier supplier, or did we pay for urgent freight?
• Usage variance: (83,000 − 80,000) × 4.20 = SAR 12,600. A question for production: did scrap rise, did sheet quality change, or is the BOM out of date?

Labor variances

Standard: 3,000 hours × 40 = SAR 120,000. Actual: 3,250 hours at SAR 39 = SAR 126,750.

• Rate variance: (39 − 40) × 3,250 = SAR 3,250 favorable.
• Efficiency variance: (3,250 − 3,000) × 40 = SAR 10,000 adverse.

Net labor variance is SAR 6,750 adverse. Splitting it turns one uncomfortable total into specific questions for specific people, which is the whole point.

From Cost of Production to Cost of Goods Sold

Cost of production covers what was made. Cost of goods sold covers what was sold. The gap sits in inventory. Opening finished goods SAR 150,000, plus cost of production SAR 780,000 (2,000 × 390), minus closing finished goods SAR 210,000, gives COGS of SAR 720,000.

At period end, test net realizable value. If a slow-moving item can now only be sold below cost, IAS 2 requires it to be written down. For more on pricing from full cost, see our guide to true product costing.

Break-Even Volume

With fixed costs of SAR 230,000 a month, a price of SAR 480 and variable cost of SAR 315, each door contributes SAR 165. Break-even is 230,000 ÷ 165, roughly 1,394 doors a month. Sales managers tend to find this number more useful than any cost report because it tells them the floor they have to clear every month.

How an ERP Calculates Production Cost

A spreadsheet handles one product. Forty products, three hundred raw materials and weekly price changes need a system that captures data where it is created:

• Purchasing and inventory: each receipt is posted at landed cost, and material cost updates automatically under weighted average or FIFO.
• Multi-level BOMs: quantities and scrap factors for every finished and semi-finished item, with costs rolled up from the lowest level.
• Production orders: actual material issues, labor hours and machine hours per order, so actual sits next to standard.
• Payroll: fully loaded employee cost for the labor rate.
• Fixed assets: machine depreciation posted to the right cost centers.
• Accounting: work in progress, finished goods and cost of sales entries posted without rekeying.

Tranquil's manufacturing pages cover multi-level BOM, material planning, production scheduling, quality check and barcode integration, alongside inventory, financial accounting, payroll and asset management. For how these ideas apply in Saudi plants specifically, read our guide to manufacturing costing in Saudi Arabia.

A Practical Rollout Plan

1. List every cost element and mark it fixed or variable.
2. Audit BOMs against actual consumption over several batches and fix quantities and scrap factors.
3. Design cost centers and drivers around major machines or machine groups, using drivers that reflect what really causes the cost.
4. Set normal capacity from historical output with planned maintenance, not theoretical maximum.
5. Run in parallel for a full month and explain every large difference before switching.
6. Hold a monthly variance meeting with purchasing, production and finance, and give each significant variance an owner and an action.

Mistakes to Avoid

• One average cost for all products, which hides the losers behind the winners.
• Ignoring scrap and rework. A rejected batch that goes back for repair consumes labor and machine time that belongs on a separate rework order.
• Loading fixed overhead on actual output in slow months, which inflates inventory and conflicts with IAS 2.
• Including recoverable VAT in material cost, which overstates it by 15%.
• Standards nobody revisits. A standard set two years ago no longer measures anything.

Frequently Asked Questions

What is the difference between cost of production and cost of goods sold?

Cost of production is what you spent making goods in the period. COGS is the cost of what you sold. COGS equals opening inventory plus cost of production minus closing inventory.

How often should standard costs be updated?

At least quarterly, and monthly for volatile inputs such as steel, copper and polymers. Annual updates alone leave standards meaningless well before year end in many industries.

Is activity-based costing worth it for a small plant?

If your products are similar in complexity and setup time, standard costing is enough. If they differ widely in setups and inspections, an activity-based analysis exposes hidden cross-subsidies, and you can run it alongside the books.

How should I treat a month with low output?

Allocate fixed overhead on normal capacity and expense the unabsorbed portion in the period, so unit cost and inventory are not artificially inflated.

Can Tranquil support production costing?

Tranquil brings multi-level BOMs, material planning, production scheduling, inventory and accounting together in one cloud ERP, which provides the data costing depends on. Talk to the Tranquil team about the right costing setup for your plant.