A weighing scale is legal for trade in India when its model is government-approved and the unit carries a valid Legal Metrology stamp. The inspector verifies and stamps it before it is first used to sell goods by weight. The stamp is not permanent: weighing instruments must be re-verified every 12 months, and again after any repair. India's approvals use the accuracy classes of OIML R 76, under which a scale in service may err up to twice as much as it may at verification.
What makes a scale legal for trade in India
Behind the phrase sits the Legal Metrology Act. The Press Information Bureau describes the Legal Metrology Act, 2009, in force since 1 April 2011, as requiring weights and measures to be verified and stamped before commercial use. In practice, four things make a scale fit for trade:
- An approved model. Makers and importers need model approval from the central government before making or importing a weighing instrument. Each approval carries a model approval mark and states the accuracy class.
- A stamp on the unit. A weight or measure may not be used in a transaction until a Legal Metrology officer has verified and stamped it.
- Re-verification on time. Weighing instruments are re-verified every 12 months; weights, beam scales and length measures every 24 months.
- Licensed hands. Under Section 23 of the Act, no one may make, repair or sell weights and measures without a licence (called a registration certificate under the 2026 amendments), as Rajasthan's Legal Metrology department explains.
The verification certificate must also be displayed in a conspicuous place where the scale is used.
Which scales must be verified and stamped
Any scale used "in any transaction or for protection" must be verified, in the words the Jammu and Kashmir Legal Metrology department uses. That covers kirana and sweet shop counters, vegetable carts, mandi platform kantas, dairy milk collection scales and weighbridges. The PIB adds clinical weighing machines to the list, and says the Legal Metrology (General) Rules cover around 40 types of instrument, including electronic weighing machines and weighbridges. Omace supplies clinic and hospital scales, such as the Venus EPS-2003 clinical weighing scale, stamped on request, and the buyer pays the state's verification fee.
Three uses are exempt from verification and stamping: weights and measures used in factories making arms and ammunition for the armed forces, those used for scientific investigation or research, and those made only for export. A scale used only at home is not used in a transaction, so it needs no stamp.
Accuracy classes for trade scales
OIML R 76 sorts non-automatic scales into four accuracy classes, and Indian approvals name the same classes. Omace's Om-PS platform scale series, for example, is a Legal Metrology approved model, approved in accuracy class III; its approved 500 kg model has e = 50 g and Min 1 kg, which is 20e.
| Class | Name | Verification interval (e) | Number of intervals (n) | Minimum capacity |
|---|---|---|---|---|
| I | Special accuracy | 0.001 g or more | 50,000 or more | 100e |
| II | High accuracy | 0.001 g to 0.05 g | 100 to 100,000 | 20e |
| II | High accuracy | 0.1 g or more | 5,000 to 100,000 | 50e |
| III | Medium accuracy | 0.1 g to 2 g | 100 to 10,000 | 20e |
| III | Medium accuracy | 5 g or more | 500 to 10,000 | 20e |
| IIII | Ordinary accuracy | 5 g or more | 100 to 1,000 | 10e |
The class, Max, Min and e must be marked on the scale itself, so the data plate tells you which row applies. Omace's Venus CHS mechanical hanging scale, a dial scale, is a Legal Metrology approved model in class IIII; its approved 100 kg model has e = 500 g and Min 5 kg, which is 10e.
How much error a trade scale may have
Allowed error is counted in verification intervals. At verification, a class III scale may be off by ±0.5e up to 500e, ±1e from 500e to 2,000e and ±1.5e above 2,000e. In service the limits double.
Take a 300 kg platform scale verified with e = 100 g, so n = 3,000. At verification it may be off by ±50 g up to 50 kg, ±100 g up to 200 kg and ±150 g up to 300 kg. In service those limits double to ±100 g, ±200 g and ±300 g.
Omace's approved 500 kg platform model works the same way. With e = 50 g, n is 10,000, so at verification it may be off by ±25 g up to 25 kg, ±50 g up to 100 kg and ±75 g up to 500 kg. In service the limits are ±50 g, ±100 g and ±150 g.
The display step can be finer than e. OIML R 76 requires Max, Min and e to be marked on the scale, and the display step d as well when it is smaller than e. A scale that shows 10 g steps is judged on its e, so read the data plate, not the display.
Acceptance and maintenance tolerance
Buyers who read US guidance meet two terms for the same idea. In the United States, NIST Handbook 44, now in its 2026 edition, sets the specifications and tolerances that many state weights and measures offices adopt for trade devices. US inspectors speak of acceptance and maintenance tolerances; OIML R 76, and the Indian approvals that follow its classes, speak of limits at verification and in service, with the in-service limit twice the verification limit.
How a platform scale is verified
OIML R 76 lists what an inspector checks at verification:
- Weighing test at about five loads from the minimum to the maximum capacity.
- Zero and tare accuracy.
- Repeatability: the same load weighed several times may not vary by more than the allowed error.
- Off-centre loading: a third of the maximum capacity placed on each quarter of a platform with up to four load cells, or 1/(n−1) of it over each support when there are more than four.
The test weights must have an error below one third of the scale's allowed error. For large scales tested where they stand, R 76 allows a substitute load, provided standard weights make up at least half of the capacity, or one third or one fifth if the scale repeats closely.
A scale that passes is stamped with the inspector's seal and gets a verification certificate. In Rajasthan, owners apply online and the certificate is digitally signed. Weights and measures can be verified at a Legal Metrology office or camp, while weighbridges and other fixed instruments are verified where they are installed.
Calibration and verification: what an owner may do
An owner may check a stamped scale at any time with known test weights. Adjusting it is different. OIML R 76 requires the calibration adjustment of class II, III and IIII scales to be sealed, and the Legal Metrology seal covers it, so a stamped scale cannot be recalibrated without breaking the seal. Only a registered repairer may recalibrate it.
If a check shows a fault, a registered repairer must fix it, and the scale must be re-verified and stamped before it is used for trade again. The same applies when a fixed scale is dismantled and reinstalled at another place. Owners can take scales to the district inspector themselves; using a licensed dealer or repairer for verification is allowed in Rajasthan but not mandatory.
When a stamp lapses or a scale fails
Book re-verification early. Assam asks owners of instruments that cannot be moved to report at least 30 days before the due date. Jammu and Kashmir asks for online applications 30 days ahead and charges a late fee of 50 per cent of the fee for every quarter of delay.
A scale that fails gets a rejection certificate in Jammu and Kashmir. If an authorised repairer fixes it within seven days, it is re-verified for half the fee.
The penalty regime has softened but still applies. The PIB notes that the Jan Vishwas Act, 2023 replaced imprisonment with money penalties in seven sections of the Legal Metrology Act from 1 October 2023. The Jan Vishwas Act, 2026 added an improvement notice for first-time record-keeping lapses, so MSMEs can correct them before a penalty.
Omace scales for trade use
For shops, a commercial weighing scale handles counter sales; for sacks, crates and drums, a platform weighing scale takes the load on the floor. These Omace models are sold today, with prices including GST from October 2026.
| Model | Capacity and step | Pan or platform | Best for | Price |
|---|---|---|---|---|
| Omace Om-TT-ECO kirana weighing machine | 10 kg x 1 g or 20 kg x 2 g | 160 x 190 mm stainless steel pan | Grocery counters | ₹2,200 |
| Omace Om-PS-SS stainless steel platform scale | 100 kg x 10 g to 300 kg x 20 g | 400 to 600 mm stainless steel | Meat, fish, dairy, wet areas | ₹6,000–₹8,600 |
| Omace Om-PS-MS platform kanta, 500 kg | 500 kg x 50 g | 600 mm mild steel | Sacks and drums | ₹8,900 |
| Omace Om-PS-MS platform kanta, 1,000 kg | 1,000 kg x 100 g | 750 or 900 mm mild steel | Pallets and heavy crates | ₹26,999–₹29,999 |
The Omace Om-TT-ECO kirana weighing machine, the Omace Om-PS-SS stainless steel platform scale and the Omace Om-PS-MS platform kanta all run on mains power with a built-in battery backup of about two days. Omace platform scales carry no IP rating, so wipe even the stainless steel model with a damp cloth and keep water away from the indicator.
Buying a trade scale from Omace
Omace Brands Private Limited has made and supplied weighing scales in India since 1994, from Bagru, Jaipur. Omace checks every scale before dispatch. Its Om-TT shop, Om-PS platform, Om-CK chicken and OM-CS crane scale series are Legal Metrology approved models in accuracy class III. RS-232 or USB data output is available on request on 8690277199. Scales bought from the Omace store carry a 2-year warranty on manufacturing defects, excluding batteries and physical damage, and Omace delivers PAN India. Maintenance is supported on request, and the buyer pays shipping, labour and other costs. There is no fixed AMC package; for small issues, Omace guides the buyer by phone. More about Omace. Omace scales are made in India. As a manufacturer, Omace Brands Private Limited holds ISO 9001:2015, ISO 13485:2016 and EU MDR quality certificates, and CE and US FDA compliance certificates; each is listed with its certificate number on the Omace certificates page. Omace shop, platform, chicken and crane scales leave the Bagru factory verified and stamped by Legal Metrology.
For a counter scale, see how to calibrate a 30 kg kanta; for vehicles, weighbridge calibration; and for the basic method, how to calibrate a digital weighing scale.
