What is production cost variance?
Production cost variance is the gap between what a batch should have cost and what it actually cost. You split it into material price, material usage, labour and overhead variances to find the cause. For Singapore manufacturers, the standard sets the benchmark, and SFRS rules decide how the actual cost lands in inventory.
Think of it like a household budget for groceries. You planned S$200 for the week and spent S$240. The S$40 gap is the variance. To fix it, you need to know whether prices rose or you simply bought more.
This guide is for finance managers, production heads and owners of Singapore plants. It covers the following topics.
- The main types of production cost variance and their formulas.
- A worked S$ example for a local food manufacturer.
- Singapore accounting and GST points that affect product cost.
- A decision table for which variances to investigate first.
- A checklist with a good answer and a red flag per control.
The main types of production cost variance
Total variance tells you that something went wrong. The split tells you what went wrong. Each type points to a different owner in the business.
| Variance | Formula | Usual owner |
|---|---|---|
| Material price | (Actual price − standard price) × actual quantity used | Procurement |
| Material usage | (Actual quantity − standard quantity for actual output) × standard price | Production |
| Labour rate | (Actual rate − standard rate) × actual hours | HR or production |
| Labour efficiency | (Actual hours − standard hours for actual output) × standard rate | Production |
| Overhead | Actual overhead − overhead applied to production | Finance and plant management |
A positive result means you spent more than planned. Accountants call that an adverse or unfavourable variance. A negative result is favourable. Both deserve a look, because a big favourable variance can hide a bad standard.
Price and usage variances work like a fuel bill. The price variance is the cost per litre at the pump. The usage variance is how far the car went on each litre. You can pay more per litre and still spend less if you drive better.
Standard cost, BoM estimate and actual cost
Every variance needs a benchmark. In most plants, that benchmark comes from the bill of materials, or BoM. The BoM lists the materials and quantities to make one unit. Routings add the steps, machines and time.
A standard cost goes one step further. It fixes approved prices and rates for a period, often a year. Finance then measures actual results against those fixed numbers. A BoM estimate that changes with every price update is not the same thing.
Decide which benchmark you use before you analyse anything. Mixing the two makes variances hard to explain. Our guide to bill of materials management in Singapore covers how to keep the BoM accurate.
Consider a Senoko metal stamping plant. Its BoM says 1.2 kg of steel per bracket. The standard price is S$2.00 per kg, fixed in January. When steel rises in June, the standard stays put, so the price variance shows the full rise.
Worked S$ example for a food manufacturer
Here is an illustrative case. A Woodlands sauce manufacturer makes chilli sauce in 1,000-bottle batches. The standard and actual figures for one batch are shown below. All amounts are before GST.
| Item | Standard | Actual |
|---|---|---|
| Chilli paste | 300 kg at S$4.00 | 320 kg at S$4.20 |
| Labour | 40 hours at S$18.00 | 46 hours at S$18.00 |
| Overhead | S$600 applied | S$680 incurred |
| Output | 1,000 bottles | 1,000 bottles |
Start with materials. The standard material cost is 300 × S$4.00 = S$1,200. The actual cost is 320 × S$4.20 = S$1,344. The total material variance is S$144 adverse.
- Price variance is (S$4.20 − S$4.00) × 320 kg = S$64 adverse.
- Usage variance is (320 − 300) × S$4.00 = S$80 adverse.
- Labour efficiency variance is (46 − 40) × S$18.00 = S$108 adverse.
- Overhead variance is S$680 − S$600 = S$80 adverse.
The batch should have cost S$2,520. It actually cost S$2,852. The total gap is S$332 adverse, or about 33 cents per bottle.
Now the story is clear. Procurement paid 5 % more for paste, which explains S$64. Production used 20 kg too much paste and six extra hours. Those two together explain S$188, so the shop floor is the bigger issue.
Singapore accounting and GST points
Variances do not live only in management reports. They also affect the value of your stock in the books. Singapore companies follow accounting standards overseen by ACRA.
Companies report under SFRS or SFRS(I), depending on their type. For inventory, SFRS(I) 1-2 matches the international standard IAS 2. Inventory cost includes materials, direct labour and a fair share of production overhead. Abnormal waste is not part of inventory cost and goes straight to expense.
So you must decide what counts as normal loss. A small, expected trim loss belongs in product cost. A spoiled batch from a machine failure is abnormal. That cost should be expensed in the period, not spread over good units.
GST matters too. GST in Singapore is 9 %. For a GST-registered manufacturer, GST paid on materials is usually claimable input tax, not part of material cost. Keep it out of your standard prices, or your price variances will be overstated by 9 %.
Imported materials need extra care. Import GST can be claimed only by the importer of record on the import permit. GST re-billed by a freight forwarder is not your input tax. Check this with your logistics partner before you set standard landed costs.
Which variances to investigate first
You cannot chase every cent. A simple rule helps you focus on what matters. Use both size and pattern to decide.
| Situation | Action | Why |
|---|---|---|
| Variance above 5 % of standard cost | Investigate this month | Likely a real problem, not noise |
| Same variance three months running | Investigate and review the standard | The standard may be out of date |
| Large favourable variance | Check the standard and the records | May hide a bad standard or a missed entry |
| Small one-off variance | Note it and move on | Cost of chasing exceeds the saving |
| Usage variance with high scrap | Check scrap reasons and machine logs | Points to process or quality issues |
Set your own thresholds based on margin. A plant with a 10 % margin cannot ignore a 5 % cost overrun. A specialty producer with higher margins may set a wider band.
A Tuas plastics moulder uses this approach. It reviews any job over 5 % adverse each Monday. Repeat offenders go to a monthly standard review. Small one-offs are logged but not chased.
How to set and update cost standards
A variance is only as good as its standard. A standard that is too loose hides waste. One that is too tight makes every batch look like a failure.
- Start from the BoM and routing for each product.
- Price materials at agreed supplier prices, before claimable GST.
- Set labour hours from timed runs, not guesses.
- Use real payroll costs to set labour rates.
- Set overhead rates from the yearly overhead budget and expected machine hours.
- Add an allowance for normal loss, such as trim or evaporation.
- Approve the standards and record the date they take effect.
Review standards at least once a year. Update them sooner after a major price change, a new machine or a recipe change. Keep the old standards on file so past variances still make sense.
A Kallang printing firm learned this the hard way. Its paper standards were three years old. Every job showed an adverse price variance, so managers stopped reading the report. A fresh set of standards made the report useful again.
KPIs that sit alongside cost variance
Variances explain cost. A few operating KPIs explain why cost moved. Track them on the same monthly report.
| KPI | Formula | What it shows |
|---|---|---|
| Cost variance % | (Actual cost − standard cost) ÷ standard cost | Overall cost control per order |
| Scrap rate | Scrap quantity ÷ total input | Waste and quality cost |
| Yield | Good output ÷ material used | How well materials turn into product |
| Capacity utilisation | Loaded hours ÷ available hours | Bottlenecks and overtime risk |
| OEE | Availability × performance × quality | Overall equipment productivity |
Yield is like the juice you get from a bag of oranges. If 100 kg of oranges gives 45 litres instead of 50, you have a yield problem. That shows up as an adverse usage variance in the cost report.
Common root causes behind each variance
Each variance has a short list of usual suspects. Knowing them speeds up the search. Ask these questions first.
- Material price. Did the supplier raise prices, or did a buyer skip the agreed pricelist?
- Material usage. Was there extra scrap, a wrong mix, or a BoM that is out of date?
- Labour efficiency. Did a machine break down, or did a new operator need more time?
- Labour rate. Was there overtime, or a pay rise not yet in the standard?
- Overhead. Did utilities rise, or did lower output spread fixed costs over fewer units?
Data quality is a hidden cause. A production record entered three days late can shift cost between batches. So can a stock issue booked to the wrong job. Fix the records before you blame people.
Read more about indirect costs in our guide to manufacturing overhead cost. It explains how overhead is spread across products.
Cost variance control checklist
Use this checklist to test your costing process. Each row lists a good answer and a red flag. Fix the red flags before you trust your variance reports.
| Control | Good answer | Red flag |
|---|---|---|
| Benchmark | Approved standards or BoM costs with a review date | Nobody knows where the standards came from |
| Production records | Entered the same day, with output and rejects | Entered in bulk at month end |
| Scrap reasons | Every scrap entry has a reason code | Scrap is booked as a stock adjustment |
| Labour hours | Hours booked against each job or operation | Hours split evenly across jobs |
| Overhead | Applied at a rate, then compared to actual | Actual overhead never reconciled |
| GST | Claimable GST kept out of material cost | Standard prices include GST |
| Review | Monthly variance review with named owners | Variances seen only at year end |
Spreadsheet or integrated system?
Many plants track variances in spreadsheets. This works for a few products and one line. It breaks down as volume grows. The table below helps you decide.
| Situation | Spreadsheet | Integrated system |
|---|---|---|
| Few products, one line | Usually enough | Optional |
| Many BoMs and routings | Hard to keep in sync | Recommended |
| Costs needed per batch | Slow and manual | Recommended |
| Monthly overhead actualisation | Error-prone | Recommended |
A spreadsheet is like counting cash by hand at a hawker stall. It works at a small scale. A busy chain needs a till that records every sale as it happens.
How HashMicro supports production cost control
HashMicro's manufacturing software collects cost on every manufacturing order. Consumed materials are taken at inventory cost. Labour and overhead are applied using work centre cost rates. The MO Cost Report then compares actual cost with the BoM standard.
Several reports help with the split. Labour has its own Labor Variance report. Material usage comes from the Material Usage Report. Scrap is recorded with reason types and shows in the Material Scrap Report.
At period end, Cost Actualization spreads actual overhead across the period's manufacturing orders. Non-payroll overhead is first booked by journal entry. An AI Cost Variance Analysis page then helps explain the gaps. Overhead variance has no dedicated report, so plan to review it from the actualised figures.
Planning tools sit alongside costing. The Master Production Schedule and MRP net material needs against stock and open orders. MRP results can be submitted as purchase requests for missing materials. This keeps planned usage and purchasing in step.
See your own batch costs in action. Book a demo and bring one real BoM with its actual usage. Ask the team to run it through an order and show the MO Cost Report.
Frequently asked questions
What is a favourable production cost variance?
It is when actual cost is lower than the standard. It sounds good but needs checking. It can mean the standard is too high or an entry is missing.
How often should we review cost variances?
Review them monthly at a minimum. Plants with thin margins often review weekly. Review standards themselves at least once a year.
Should GST be included in standard material costs?
Not if your business is GST-registered and can claim input tax. Claimable GST is not part of material cost. Keep standards before GST to avoid inflated price variances.
What is the difference between price and usage variance?
Price variance shows the effect of paying more or less per unit. Usage variance shows the effect of using more or less material. Together they make up the total material variance.
Where do abnormal losses go in the accounts?
Abnormal losses are expensed in the period they happen. They are not added to the cost of good units. Normal, expected losses stay in product cost.
For related topics, read our guides to understanding production cost and job costing. Both build on the ideas in this guide.
