We get asked some version of this question almost every day: "Which thermometer do I need?" The honest answer is that it depends on what you're measuring, how hot or cold it gets, and how close you can get to it. Here's how we usually walk people through it.

Start with the sensor, not the display

Most digital thermometers are really just a readout attached to one of four sensor types. Once you know which sensor fits your job, the rest of the choice gets a lot easier.

Thermocouples

A thermocouple is two different metal wires joined at the tip. Heat that junction and it produces a tiny voltage the meter converts to a temperature. They're tough, they respond quickly, and they cover a huge range. That's why you'll find Type K probes in kitchens, ovens, kilns and factory floors alike. The trade-off is accuracy: a thermocouple is usually good to a degree or two, not tenths.

If you're working with an oven, a fryer, a heat-treat process or anything that gets truly hot, start with our thermocouple thermometers and probes.

Thermistors

Thermistors are small resistors that change value with temperature. Over a narrower range they're more precise than a thermocouple and very stable, which makes them a good fit for food safety checks, refrigeration and HVAC work. They don't handle extreme heat well, so they're not the right choice for a pizza oven.

See our thermistor thermometers and probes.

RTDs

An RTD (resistance temperature detector) uses a platinum element and is the go-to when accuracy and long-term stability matter most, think lab work, process control and reference checks. They cost more and are a bit slower to respond, but they hold their calibration well.

Infrared (non-contact)

An infrared thermometer reads the heat coming off a surface, so you never have to touch it. That's handy for moving parts, electrical panels, griddles or anything you can't safely reach. Keep in mind it only sees the surface. It won't tell you the internal temperature of a roast or the air temperature in a room, and shiny surfaces can throw the reading off.

Browse our infrared thermometers.

A few questions that narrow it down

• What's the temperature range? Very hot jobs usually point to a thermocouple. Everyday food and refrigeration work suits a thermistor.
• Surface, air, liquid or inside the product? That decides the probe style more than anything else.
• Do you need a record? If someone (an inspector, a customer, your QA manager) wants to see temperatures over time, a data logger will save you a lot of clipboard work.
• Do you need it certified? Many of our instruments can be ordered with a NIST traceable certificate.

Still not sure?

That's what we're here for. We've been helping customers sort this out since 1990, and a quick call usually settles it. Tell us what you're measuring and we'll point you to two or three options that make sense. You can also browse everything in our thermometers and temperature measuring products collections.