Test weights

A scale that is never checked is a scale you cannot be sure is accurate. With a test weight you can establish yourself, between two calibrations, whether your instrument is still working within tolerance. The same weights are also called check weights, calibration weights or mass standards; it is the same product. We supply them individually and in sets, from a few milligrams to heavy stacking weights, with a calibration certificate. And because a test weight drifts too, we calibrate and adjust the weights you already have in our own laboratory.

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We don't just supply it, we keep it in good shape

  • Installation on site (optional)We come to level it and set it up on your floor, and keep it accurate with an annual inspection and calibration.
  • Verified from the factoryWe supply scales verified from the factory; the initial verification is carried out by the manufacturer, and re-verification is arranged through the manufacturer.
  • Calibration certificate for ISO, HACCP and GMPTraceable to standards, including the measurement uncertainty - usable in your quality system.
  • Calibration to EURAMET cg-18The European guideline for non-automatic weighing instruments: linearity, repeatability and eccentricity.

More about verification, calibration and maintenance

Choose a type

Buying test weights and having them calibrated

The OIML classes: which one do you need?

The OIML R111 standard classifies weights hierarchically from E1, the most accurate, to M3, the coarsest. The underlying rule is simple: your scale can never be more accurate than the weight you check it with. The tolerance of the weight must therefore be well within the readability of your instrument. Roughly:

  • E1 and E2 — for analytical and semi-micro balances with the highest resolution, readability from 0.1 mg.
  • F1 and F2 — for precision and laboratory balances.
  • M1, M2 and M3 — for industrial and commercial scales, floor scales, pallet scales and weighbridges.

A weight of too low a class makes your check worthless; a higher class than necessary is expensive and requires stricter handling and storage. If you do not know which class suits your scale, send us the capacity and the division and we will work it out for you.

MASSLAB: calibrating and adjusting your own weights

Buying new weights is often unnecessary. In our MASSLAB laboratory we check, adjust and certify existing test weights to OIML R111 in classes M1, M2 and M3, up to 2000 kg per piece. If your weights have drifted out of tolerance through wear, corrosion or damage, we readjust them where possible instead of rejecting them, and you receive a certificate proving that they are back within the standard. That is usually considerably cheaper than replacing them, especially with heavy stacking weights. If you work with weights in classes E or F, ask about the options.

Why your weights need to be checked periodically

A test weight is a measuring standard, not a tool. A scratch, a fingerprint, corrosion or a drop changes the mass, and with it the value of every check you do with it. So never handle weights with bare hands but with tweezers or gloves, keep them in the case supplied, and do not leave them loose in a drawer with other items. If you work under a quality system, you must also be able to demonstrate that your references are traceable and have been recalibrated periodically; without that proof the whole chain of your measurements is unsupported.

Related categories

For the instruments themselves: analytical balances, precision balances, laboratory balances and floor scales. For calibration of your weighing equipment, on site or in our workshop, see our verification and calibration service.

Which brands

Here we carry Kern, Baxtran and Adam. These are brands we are a dealer for, and we are authorised by the manufacturer to repair and recalibrate their test weights.

Test weights or check weights - the same thing

Both terms are used equally often and mean exactly the same. In the standard it is called a weight of a particular accuracy class; in practice some people say test weights and others say check weights. If you searched for test weights, you will find the same range on this page.

Which class do you need

The class determines how close the weight is to its nominal value. E1 and E2 are for the laboratory and for calibrating analytical and precision balances; F1 and F2 for precision balances and checkweighing scales; M1, M2 and M3 for bench, floor and crane scales. The rule of thumb: the test weight should be one class more accurate than the scale you are checking with it.

From 1 mg to 2 tonnes

The range runs from individual weights of one milligram to block weights of two tonnes. Individual pieces, weight sets in a case or box, and the matching tweezers, gloves and cassettes. The material is stated for each range - polished stainless steel for the fine classes, painted cast iron for the heavy ones.

With a certificate, and we calibrate in-house

A calibration certificate is available for almost every test weight; a DAkkS certificate for Kern, an ENAC certificate for Baxtran. These are listed as accessories with the weight itself, with the nominal value and class in the name. You can also have your check weights periodically recalibrated by us - see verification, calibration and repair.

Maintenance, calibration and repair

We calibrate and adjust test weights in our own laboratory, Masslab, in OIML classes E2 to M3; the certificates are then available in the Masslab customer portal. See calibration with a certificate and what a calibration certificate contains.

Frequently asked questions

What is the difference between test weights and check weights?

None. They are two words for the same thing: a weight with a known mass and a defined accuracy class, used to check a scale or have it calibrated.

Which class of test weight suits my scale?

As a rule of thumb, one class more accurate than the scale itself. For an analytical balance E2, for a precision balance F1, for a bench or floor scale M1. If in doubt, give us a call with the make and type to hand.

Do I get a certificate with it?

With almost every range you can order a calibration certificate; it is listed as an accessory with the weight. We also calibrate and recalibrate in-house.

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