Short-weighted at a market or corner shop in Peru: what can you do?

Scales used for selling are under state control

A scale used to sell goods is not just any device. Ley 30224, the law that created Peru’s National Quality Institute (INACAL), says:

“El control metrológico se realiza a todo medio de medición utilizado en operaciones de carácter comercial, valorización de servicios, de trabajos, pruebas periciales, salud pública y seguridad del trabajo, oficinas públicas y en todas aquellas actividades que determine el órgano de línea responsable de la materia de metrología del INACAL directamente o en coordinación con otros organismos oficiales.”

(Metrological control applies to every measuring instrument used in commercial operations, among other activities.)

For scales, INACAL set this out in Resolución Directoral 006-2018-INACAL/DM. Article 1 approves “el control metrológico (aprobación de modelo, verificación inicial, verificación posterior) de las balanzas utilizadas en transacciones comerciales a nivel nacional” (model approval, initial verification and later verification of scales used in commercial transactions nationwide). Article 2 says it covers commercial scales “que tengan como capacidad máxima de medición hasta 100 kilogramos” (with a maximum capacity of up to 100 kilograms), which must meet Peruvian Metrological Standard NMP 003.

That is the usual scale at a bodega, a butcher’s or a market stall.

The seller is responsible for the scale

The same resolution puts the responsibility on the seller. Article 5 says:

“los comerciantes que utilicen balanzas en transacciones comerciales son responsables de su correcto funcionamiento y de solicitar su verificación inicial y posterior mientras se encuentren en uso”

(Traders who use scales in commercial transactions are responsible for their proper working and for requesting their initial and later verification while in use.)

Article 4 sets the frequency: “la verificación periódica se realizara cada doce meses después de la primera verificación” (periodic verification every twelve months after the first).

In practice: if the scale weighs short, the seller cannot hide behind “that’s just the scale”. Keeping it accurate is their job.

Who inspects: your municipality

Ley 30224 gives municipalities a direct role. Article 36.4 says:

“Las municipalidades y entidades públicas, dentro del ámbito de su competencia, son responsables de fiscalizar que los instrumentos sometidos a control metrológico estén debidamente verificados […]”

(Municipalities and public bodies, within their remit, are responsible for checking that instruments under metrological control have been verified.)

The Municipalities Law (Ley 27972) points the same way. Among the exclusive functions of district municipalities, article 83 lists:

“Realizar el control de pesos y medidas, así como el del acaparamiento, la especulación y la adulteración de productos y servicios.”

(Controlling weights and measures, as well as hoarding, speculation and adulteration of goods and services.)

So if you think a stall’s scale is off, your district municipality is the authority to tell so it can inspect it.

Your case as a consumer: Indecopi

A bodega or market stall is a supplier under the Consumer Protection Code (Ley 29571), which covers anyone who sells “al por mayor, al por menor, productos o servicios destinados finalmente a los consumidores, aun cuando ello no se desarrolle en establecimientos abiertos al público” (wholesale or retail to end consumers, even outside an establishment open to the public).

Three articles of the Code matter here:

• Article 3 bans “toda información o presentación u omisión de información que induzca al consumidor a error respecto a […] volumen, peso, medidas, precios […] cantidad” (any information, presentation or omission that misleads the consumer about volume, weight, measures, prices or quantity). If they say “one kilo” and give you less, you are being misled about the weight.
• Article 18 defines idoneidad (fitness) as “la correspondencia entre lo que un consumidor espera y lo que efectivamente recibe” (the match between what the consumer expects and what they actually get), based on the offer, the price and other factors.
• Article 19 says “el proveedor responde por la idoneidad y calidad de los productos y servicios ofrecidos” (the supplier answers for the fitness and quality of what it offers).

Articles 18 and 19 do not mention weight as such. Our reading is that paying for a kilo and getting less is a plain case of not getting what you were offered.

Who sanctions? Article 105 says Indecopi “es la autoridad con competencia primaria y de alcance nacional para conocer las presuntas infracciones a las disposiciones contenidas en el presente Código” (is the primary national authority for alleged breaches of the Code).

Municipality and Indecopi are not either-or

They are two routes with different goals:

You can use both. Start with the business’s complaints book, which gives you a written record. To choose your route with Indecopi, see reclamo, queja and denuncia explained and how to file a complaint with Indecopi.

How to prove it

Proof is the hard part in these cases. Some practical tips:

• Watch the scale display before they take the item off. Check that it shows zero with nothing on it.
• If you can, weigh what you bought on another scale in the same market and photograph both readings.
• Ask for a boleta or ticket showing weight and price.
• Note the stall number or name, the address and the time.

What this page does not cover

We did not read Peruvian Metrological Standard NMP 003, so we do not say how much error a scale may have. We do not cover pre-packed products that weigh less than their label says, which have their own labelling rules. Nor did we review Indecopi decisions on short weight, or the fines each municipality can impose, which depend on its own ordinances.