Weighing Scale Calibration: The Quiet Check That Protects Your Business

Most scales don't break dramatically. They just drift a little. A gram here, a few grams there, and nothing looks wrong until a customer complains, a batch fails a check or an auditor asks to see your records.

That slow, sneaky drift is exactly why weighing scale calibration matters. At Blake and Boughton, we've spent over two decades calibrating, repairing and supplying industrial weighing equipment, so here's what we'd tell you over a cup of tea.

So, what is weighing scale calibration?

Think of it as a health check for your scale. We place known, certified references on it, compare what it reads with what it should read, and adjust it if there's a gap.

The key word is traceable. It means the references link back to national standards, so your results stand up when a customer, auditor or regulator asks questions.

It isn't only for small bench scales, either. We calibrate industrial scales, electronic balances, moisture analysers, floor scales, weighbridges, vessels and silos. Usually that means certified test weights, though for large vessels we may use a calibrated flow meter or a calibrated DC millivolt source instead.

How do you know it's time?

Your scale will usually give you a hint. Maybe the same item weighs differently twice in a row, the zero reading wanders, or the result changes depending on where you place the load. A scale that's been moved, knocked or repaired deserves a check too, and so does any scale with an audit on the horizon.

As for how often, it depends on your industry, how hard the scale works and which rules apply to you. Many businesses calibrate once a year, while industries with strict quality standards may need it more often. Dust, washdowns and temperature swings can also shorten the gap. If you're not sure, we'll recommend a schedule, and a service agreement means you never have to remember it yourself.

What actually happens on the day?

It's less mysterious than it sounds. Our technician starts with an as-found check, recording how your scale performs before touching it. If it's out, we adjust it using high-precision equipment. Then we test calibration, linearity and eccentricity, which is a technical way of asking whether the scale reads correctly across its range and when the load sits off-centre.

Finally, you get your certificate and records, giving you a complete calibration history to show anyone who asks.

That first step matters more than people expect. If your scale had drifted, the as-found result tells you by how much, which helps if you ever need to review earlier weighings.

Calibrated weights for scales, explained

Here's a question we hear a lot: can't I just use something I know the weight of?

Not really. Calibrated weights for scales are precisely made masses with a certified value, and they're the reference your scale gets measured against. That means the weight must be more accurate than the scale you're testing. A bag of sugar, a dumbbell or a full water bottle simply can't offer that, and they have no traceable certificate behind them.

If you want to check your scales in-house between visits, a few habits make a big difference:

• Match the weights to the job. Choose values close to your normal working range, and an accuracy class that suits your scale's readability.

• Handle with care. Use gloves or forceps, because fingerprints and moisture can change a weight's mass.

• Store them properly. Keep them clean, dry and in their case.

• Calibrate the weights too. Test weights can wear or corrode over time, so they need checking as well.

We supply a wide range of calibration weights, and we calibrate test weights ourselves, so you can keep everything in one place.

Which certificate do you need?

Not every job needs the same paperwork. A standard calibration certificate lists the as-found and post-adjustment results for calibration, linearity and eccentricity, and it suits most day-to-day needs.

A UKAS certificate goes further. It's multi-page and accounts for measurement uncertainty, stated at a 95% confidence level, which makes it a good fit for laboratories and heavily regulated work.

IQOQ verification and validation is built for production system validation, supporting FDA and MCA compliance. If you're unsure which one your auditor expects, ask us before you book. It saves a lot of back and forth.

Why people choose Blake and Boughton

Paul Blake and James Boughton set up the company in November 2000 after spotting a gap for a professional weighing business with excellent service and fair prices. We're still based in Thetford, Norfolk, and we don't run a call centre. You'll speak to someone who knows what a weighbridge is.

We're ISO 9001, SafeContractor and CHAS accredited, and we support major makes including Mettler Toledo, Sartorius, A&D, Ohaus and Salter Brecknell. Beyond calibration, we handle repairs, service agreements and sales, and we're rated 5.0 on Feefo from over 1,000 reviews.

Let's get your scales checked

Accurate weighing protects your product, your customers and your reputation. Whether you need a one-off visit or ongoing cover, we're happy to talk it through.

Call our service team on 01842 751555, email service@blakeandboughton.co.uk, or visit blakeandboughton.co.uk to enquire about weighing scale calibration today.