Precision balance or analytical balance: what is the difference?
Both stand in the laboratory and both are accurate, but they do different work. The difference lies in the readability, the capacity and what is needed around them to actually achieve that readability.
The numbers
| Analytical balance | Precision balance | |
|---|---|---|
| readability | 0.1 mg, 0.01 mg or finer | 1 mg to 0.1 g |
| capacity | usually 100 to 500 g | a few hundred grams to 30 kg |
| OIML class when verified | I | II |
| draught shield | always | only at 1 mg |
| warm-up time | up to an hour | a few minutes |
Why an analytical balance has a draught shield
At 0.1 mg, the air movement of a colleague walking past is already a weighing. That is why the weighing pan of an analytical balance sits in a glass cabinet with sliding doors, the balance stands on a heavy table, and it needs time to reach temperature. That is not a luxury: without those three it performs no better than a precision balance. If you regularly weigh in 10 mg and want to see that to three or four digits, you need an analytical balance; if you only do that occasionally, it is better to check whether a 1 mg precision balance with a draught shield will do.
When a precision balance is enough
Weighing out raw materials for a recipe, samples of 1 gram and more, counting small parts, checking prepackages, a pharmacy that compounds by the gram: that is work for a precision balance. It is faster, more robust, less sensitive to its environment and cheaper, and it goes up to a few kilos, which an analytical balance cannot. How to work it out is explained under what accuracy and capacity do I need.
Verified: Class I or II
For the pharmacy and the medical or pharmaceutical laboratory, the balance must be verified. An analytical balance is then verified in Class I, a precision balance in Class II. Pay attention to the verification scale interval e: on a verified laboratory balance it is often ten times coarser than the readability, and for legal purposes only e counts. All balances that can be supplied verified are listed under verified scales.
Checking and calibration
You check an analytical balance with an E2 weight and a precision balance with F1; see OIML classes explained. We calibrate both on site with a certificate, and for KERN balances we supply a DAkkS certificate; see scale calibration. The full range is listed under laboratory balances.
Frequently asked questions
Is an analysis balance the same as an analytical balance?
Yes. Analytical balance, analysis balance and analytical scale are three names for a balance that reads to 0.1 mg or finer.
Can I weigh 200 grams on an analytical balance?
If the capacity allows it, yes, and many analytical balances go up to 220 g. But then you are using a 0.1 mg instrument for something that would have been fine at 10 mg; a precision balance is faster and cheaper for that.
What is a semi-micro balance?
An analytical balance that reads to 0.01 mg, usually up to 100 or 200 g. A micro balance goes one step further, to 0.001 mg, with a capacity of a few grams.
Do I need a draught shield on a precision balance?
At 1 mg, yes; at 10 mg a simple shield is sensible, and at 0.1 g it is not needed. Without a shield, a 1 mg balance in a draughty room never settles.