CMT Factory Toolkit

Open-source utilities for CMT (Cut-Make-Trim) garment factory operations: SMV calculators, piece-rate formulas, line balancing helpers, and bundle ID generators.

Open-sourced from Scan ERP, a QR-based ERP for CMT garment factories. These utilities power our own production system; published here so other factory developers can use them.

What's Inside

cmt-factory-toolkit/
├── smv-calculator.js          # SMV = Basic Time × (1 + Allowance%)
├── piece-rate-calculator.js   # Piece-rate wage with skill multipliers + bonuses
├── bundle-id-generator.js     # Standard bundle ID format used in scan-erp
├── westinghouse-rating.js     # Performance rating tables (Skill/Effort/Conditions/Consistency)
└── examples/
    ├── shirt-smv-example.js
    ├── line-balance-example.js
    └── piece-rate-monthly.js

Quick Start

const { calculateSMV } = require('./smv-calculator');

// Calculate SMV for a sewing operation
const smv = calculateSMV({
  observedTimeSeconds: 18,        // From stopwatch
  performanceRating: 1.05,        // Westinghouse: skilled operator at 105%
  allowancePercent: 0.30,         // 30% (personal + fatigue + delay)
});

console.log(`SMV: ${smv.toFixed(2)} minutes per piece`);
// → SMV: 0.41 minutes per piece

SMV Calculator

The Standard Minute Value formula used across the garment industry:

SMV = Basic Time × (1 + Allowance%)
Basic Time = Observed Time × Performance Rating

Westinghouse Performance Rating

Rates operator performance across four dimensions:

Dimension	Range	Meaning
Skill	-0.22 to +0.15	Operator's skill level
Effort	-0.17 to +0.13	How hard they're working
Conditions	-0.07 to +0.06	Workstation environment
Consistency	-0.04 to +0.04	Cycle-to-cycle stability

Final rating = 1.0 + sum of all four adjustments.

Read full SMV guide on Scan ERP →

Piece-Rate Calculator

Standard piece-rate wage formula used in CMT factories:

const { calculatePieceRate } = require('./piece-rate-calculator');

const wage = calculatePieceRate({
  pieces: 250,
  ratePerPiece: 2.50,           // Currency unit
  skillLevel: 'expert',         // novice/intermediate/expert
  qualityScore: 95,             // 0-100
  efficiencyPercent: 110,       // % of standard
  machineType: 'OVERLOCK_5THREAD',
});

// → { gross: 762.50, breakdown: {...} }

The full formula:

adjustedRate = baseRate × skillMultiplier
base = pieces × adjustedRate
+ machineComplexityBonus (5-25% by machine)
+ efficiencyBonus (tiered)
- qualityPenalty (below threshold)
= gross wage

Read full piece-rate guide on Scan ERP →

Bundle ID Generator

Standard bundle ID format used in QR-based production tracking:

const { generateBundleId } = require('./bundle-id-generator');

const id = generateBundleId({
  style: 'S27',
  lot: '8082',
  color: 'BLUE',
  size: 'M',
  bundleNumber: 1,
  component: 'FRT',
});
// → "S27-8082-BLUE-M-001-FRT"

This format encodes:

• Style number
• Lot number
• Color name
• Size
• Bundle sequence (zero-padded to 3 digits)
• Component code (FRT=Front, BK=Back, SLV=Sleeve, CLR=Collar, etc.)

Read full QR bundle tracking guide →

Use Cases

These utilities are used in:

• Real-time bundle scanning workflows
• End-of-day operator wage calculations
• Production capacity planning
• Line balancing and target setting
• CMT pricing calculators

Used in production

Powers daily operations at:

• Trishakti Apparel (Nepal, 60 operators) — original implementation
• Scan ERP customer factories across South Asia, Southeast Asia, and Africa
• 115,370+ pieces tracked using these formulas

Related Reading

• Garment Factory ERP System: Complete 2026 Guide
• Real-Time Garment Production Tracking System
• SMV Costing for CMT Pricing
• SAM Values Reference Table
• 11 Questions to Ask Before Buying Garment Factory Software

Try Scan ERP

This toolkit is free. The full ERP system that uses these utilities (with QR scanning, dashboards, payments, hardware integration) is available at scanerp.pro.

• 🌐 Live demo
• 📱 WhatsApp: +977-9863618347
• 💬 Free 30-day trial

Contributing

PRs welcome! Particularly interested in:

• Additional language translations (descriptions for Bengali, Hindi, Tamil, Khmer, Vietnamese)
• More garment-specific calculation utilities
• Real factory data examples (anonymized)
• Edge cases we haven't covered

License

MIT — use freely in commercial and non-commercial projects.

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Built by Santosh Rijal — MBBS doctor and CMT factory owner. Scan ERP is the full ERP system powered by these utilities.