LOCAL TOOLS
Explain batch costs through transparent assumptions
See how fixed costs spread across different production quantities.
An estimation model, not a supplier quote
This transparent engineering/business calculator is for estimation and scenario analysis. It does not know actual factory rates, supplier margins, capacity constraints, taxes or yield behavior. Enter your assumptions and compare their effects; it is not accurate manufacturing quotation, AI pricing or a guarantee of supplier cost.
Enter fixed and variable inputs
Per-unit inputs are material, variable processing, labor, inspection and external processing. Per-batch inputs are setup, engineering, tooling and batch inspection. Enter one or more integer batch sizes and one currency label. All scenarios use the same unit and fixed assumptions. Select decimal point or comma explicitly; thousands separators and exponent notation are unsupported.
Formula order
Variable total = quantity × sum of unit costs. Fixed total = setup + engineering + tooling + batch inspection. Material reserve = quantity × material/unit × reserve rate. Subtotal = variable + fixed + reserve. Overhead = subtotal × overhead rate, applied once. Total batch cost = subtotal + overhead; unit cost = total / quantity. Selling price = cost / (1 − gross margin), which differs from markup. Fixed dilution = fixed total / quantity.
Synthetic scenario
Use Load synthetic scenario: material 2, processing 1, labor 1, unit inspection 0.5, external 0.5, and fixed costs 10 + 20 + 30 + 40. At quantity 1, material reserve 10%, overhead 20% and margin 25%, batch cost is 126.240000 and selling price 168.320000. At quantities 10 and 100, fixed dilution falls to 10 and 1 per unit. These invented values are teaching assumptions, not market prices.
Precision, currency and sensitivity
Inputs allow at most six decimal places. Exact rational arithmetic avoids binary accumulation; output rounds half-up to six decimal places only once. USD, CNY, EUR, GBP and JPY are labels, without exchange rates or currency-specific rounding. The sensitivity chart follows supplied scenario order and is accompanied by exact table values, including unit cost and fixed dilution. It does not predict unsupplied quantities.
Local privacy and exports
Parameters and results stay in a local Worker without upload, logging of values or browser persistence. Clear/Cancel terminates the session. XLSX exports Data, Summary and Run_Settings with the formula, percentage bases and all inputs. Decimal output is text to preserve precision. CSV exports Data only; use XLSX to keep assumptions. An optional versioned XLSX input template fills the existing form after local import. Download it in the workbench, edit Value cells and quantity rows, then import. Field errors show source cells and must be corrected before calculation. This input template is separate from result XLSX; CSV input, formulas and Excel percentage formatting are not supported.
Limits and frequently asked questions
Up to 500 batch scenarios; quantity is an integer from 1 to 1 billion, costs are nonnegative up to 1 billion, reserve/overhead are 0–100%, margin is 0–less than 100%. Negative/invalid inputs block. Does reserve model yield loss? No, it is material reserve / contingency only, not actual scrap cost; it does not include processing, labor or external-processing scrap losses. Are taxes or mixed currencies included? No. Does a larger batch always lower a real quote? No: this model holds assumptions constant and shows fixed-cost dilution, not operational constraints.