IEC 60584-1 tolerance class lookup
The permitted deviation for any type, class and temperature under IEC 60584-1:2013: Class 1, Class 2 and Class 3, band by band, with the ASTM E230 equivalent where one exists.
Where two values apply the standard takes the greater of the fixed deviation and the coefficient term; the band boundaries are the temperatures where the two cross. A dash means the class is not defined for that type, not a tighter limit.
The full band table
| Type | Class | Bands (°C) | ASTM E230 equivalent |
|---|---|---|---|
| J supplied ±1.5 °C | Class 1 | -40…375 °C: ±1.5 °C 375…750 °C: ±0.004·|t| °C | Special Limits of Error |
| Class 2 | -40…333 °C: ±2.5 °C 333…750 °C: ±0.0075·|t| °C | Standard Limits of Error | |
| K supplied ±1.5 °C | Class 1 | -40…375 °C: ±1.5 °C 375…1000 °C: ±0.004·|t| °C | Special Limits of Error |
| Class 2 | -40…333 °C: ±2.5 °C 333…1200 °C: ±0.0075·|t| °C | Standard Limits of Error | |
| Class 3 | -200…-167 °C: ±0.015·|t| °C -167…40 °C: ±2.5 °C | (no equivalent) | |
| T supplied ±0.5 °C | Class 1 | -40…125 °C: ±0.5 °C 125…350 °C: ±0.004·|t| °C | Special Limits of Error |
| Class 2 | -40…133 °C: ±1 °C 133…350 °C: ±0.0075·|t| °C | Standard Limits of Error | |
| Class 3 | -200…-67 °C: ±0.015·|t| °C -67…40 °C: ±1 °C | (no equivalent) | |
| E supplied ±1.5 °C | Class 1 | -40…375 °C: ±1.5 °C 375…800 °C: ±0.004·|t| °C | Special Limits of Error |
| Class 2 | -40…333 °C: ±2.5 °C 333…900 °C: ±0.0075·|t| °C | Standard Limits of Error | |
| Class 3 | -200…-167 °C: ±0.015·|t| °C -167…40 °C: ±2.5 °C | (no equivalent) | |
| N supplied ±1.5 °C | Class 1 | -40…375 °C: ±1.5 °C 375…1000 °C: ±0.004·|t| °C | Special Limits of Error |
| Class 2 | -40…333 °C: ±2.5 °C 333…1200 °C: ±0.0075·|t| °C | Standard Limits of Error | |
| Class 3 | -200…-167 °C: ±0.015·|t| °C -167…40 °C: ±2.5 °C | (no equivalent) | |
| R supplied ±1.0 °C | Class 1 | 0…1100 °C: ±1 °C 1100…1600 °C: ±[1 + 0.003·(t−1100)] °C | Special Limits of Error |
| Class 2 | 0…600 °C: ±1.5 °C 600…1600 °C: ±0.0025·|t| °C | Standard Limits of Error | |
| S supplied ±1.0 °C | Class 1 | 0…1100 °C: ±1 °C 1100…1600 °C: ±[1 + 0.003·(t−1100)] °C | Special Limits of Error |
| Class 2 | 0…600 °C: ±1.5 °C 600…1600 °C: ±0.0025·|t| °C | Standard Limits of Error | |
| B supplied ±0.5 °C | Class 2 | 600…1700 °C: ±0.0025·|t| °C | Standard Limits of Error |
| Class 3 | 600…1700 °C: ±0.005·|t| °C | (no equivalent) |
Supply caveats from the same source: materials are normally supplied to meet these tolerances above −40 °C, and conformance to Class 3 as well as Class 1/2 requires material selection that must be stated at order time.
What each type is supplied to in our stock
| Type | Supplied tolerance | Verified range |
|---|---|---|
| Type J | ±1.5 °C | −40 … +750 °C |
| Type K | ±1.5 °C | −200 … +1370 °C |
| Type T | ±0.5 °C | −200 … +350 °C |
| Type E | ±1.5 °C | −200 … +900 °C |
| Type N | ±1.5 °C | −270 … +1300 °C |
| Type R | ±1.0 °C | 0 … +1768 °C (continuous ~1600) |
| Type S | ±1.0 °C | 0 … +1768 °C (continuous ~1600) |
| Type B | ±0.5 °C | 0 … +1820 °C (continuous ~1700) |
These are type-level figures from our own datasheets, the class the certificate proves for the batch is what governs. Two spools of the same type can both satisfy the same class and still differ from each other.
Frequently Asked Questions (FAQ)
How is the tolerance at one temperature determined?
IEC 60584-1 states each class either as a fixed deviation in °C or as a coefficient times the actual temperature, and the greater of the two governs. The band splits in the table are exactly where the two cross, for Type K Class 1, ±1.5 °C governs to 375 °C and ±0.004·|t| governs above it, which is why the limit at 1000 °C works out to ±4.0 °C.
Why does Type B have no Class 1?
IEC 60584-1 defines no Class 1 for Type B, and nothing at all below 600 °C, the Pt-30%Rh/Pt-6%Rh pair produces so little EMF at low temperature that class grading there would be meaningless. The tightest band available for Type B is Class 2 from 600 °C up.
Is IEC Class 1 the same as ASTM Special Limits of Error?
For practical purposes, yes, Class 1 corresponds to Special Limits and Class 2 to Standard Limits, with the EMF tables behind the two standards differing by less than 1 µV. Class 3 has no ASTM equivalent at all: it is an IEC-only band for low temperature service, defined only down from +40 °C.
Does the calculator tell me what our spool will measure?
No, and nothing can. The class band describes what the standard allows; the batch EMF certificate describes the spool you are holding. Materials are normally supplied to meet the table above −40 °C, and Class 3 conformance also requires material selection that must be stated at order time.
Need wire certified to a specific class?
Send the type, class and temperature span, we quote IEC 60584-1 certified thermocouple wire with a furnace-batch-traceable EMF certificate.