Calibration equipment selector

How the calculation works

1. 01Each equipment class carries a published working range and a best achievable uncertainty; a class is ruled out when the requested range falls outside its range, or when the uncertainty it can achieve is not good enough for the requirement.
2. 02Non-contact devices are matched to radiation sources and contact devices to immersion or block sources, because an infrared thermometer cannot be calibrated by immersion and a bare probe cannot be calibrated against a blackbody.
3. 03Probe diameter is checked against a dry block's well geometry, since a probe that does not fit the well, or sits in it loosely, will not reach the block temperature.
4. 04Every threshold used is returned with the result, so a verdict can be audited rather than taken on trust.

Limitations

• It recommends a CLASS of equipment, never a specific product. Ranking real instruments needs a verified product catalogue, which this site does not yet have.
• It is not a purchasing decision and not a substitute for reading a candidate's own calibration certificate and stated uncertainty.
• Temperature only. The same structure extends to other parameters, but no other parameter is implemented.
• Unlike the other tools here, this one sends what you enter to our server, because the rules live in the tested engine rather than in the browser.

Frequently asked questions

Dry block or liquid bath: which should I use?

A liquid bath generally achieves lower uncertainty and handles awkward probe shapes, because the probe is surrounded by stirred liquid. A dry block is faster, more portable and cleaner, but its uncertainty depends on the probe fitting its well properly. If your required uncertainty is tight, the bath usually wins; if you are working on site, the block usually does.

Why is my required uncertainty ruling out equipment?

Because a source cannot calibrate something to a tolerance better than the source itself achieves. If you need ±0.02 °C and a class can only deliver ±0.1 °C, that class cannot support the requirement no matter how carefully it is used.

Can I calibrate an infrared thermometer in a dry block?

Not properly. An infrared thermometer measures emitted radiation, so it needs a source of known temperature AND known emissivity — a blackbody. Pointing it at a block well gives a reading, but not a traceable one, because the emissivity of the surface it is seeing is unknown.

Does this tell me which model to buy?

No, and deliberately so. It narrows the field to the right class of equipment against published criteria. Choosing between real instruments needs their actual certificates and stated uncertainties, which only the manufacturer and your own requirement can settle.