Resistor Min/Max Calculator: Tolerance & TCR

Resistor specification

Nominal resistance

Initial tolerance (±)

TCR limit (±)

ppm/°C

Enter the absolute TCR limit from the datasheet. The result assumes either positive or negative drift for a conservative envelope.

Temperature range

Reference temperature

°C

Minimum temperature

°C

Maximum temperature

°C

Tolerance + TCR

Resistance envelope

±1.65 %

The blue band shows the possible resistance range. Amber dashed lines mark the initial tolerance at the reference temperature.

e_T = |T-T_{ref}| \cdot TCR \cdot 10^{-6}

e_{worst} = \frac{tolerance}{100} + e_T

R_{min,max} = R_N \cdot (1 \mp e_{worst})

Calculated limits

Worst-case min/max resistance

Minimum resistance9.835 kΩ

Nominal resistance10 kΩ

Maximum resistance10.165 kΩ

Total range width330 Ω

Initial tolerance±1 %

TCR contribution±0.65 %

Largest |ΔT|65 °C

Combined worst case±1.65 %

Worst-case tolerance and TCR contributions are added linearly. This is a conservative limit calculation, not a statistical RSS estimate.

Limits at each temperature endpoint

Temperature	ΔT	TCR contribution	Lower bound	Upper bound
-40 °C	65 °C	±0.65 %	9.835 kΩ	10.165 kΩ
85 °C	60 °C	±0.6 %	9.84 kΩ	10.16 kΩ

Component guide

Establish a resistor's real min/max range

Manufacturing tolerance alone does not describe the operating value. This calculation adds TCR-driven thermal drift to form a conservative envelope across the full temperature range.

Method and assumptions

The tool converts absolute TCR into relative error using |ΔT| × TCR × 10⁻⁶, then adds it linearly to initial tolerance. The temperature furthest from the reference sets the worst case. Limits are symmetrical because a ±TCR specification does not identify the actual slope direction.

Inputs to verify

Tolerance and TCR for the exact variant

Use the values for the exact resistance, package, and technology being ordered. One product series can offer several grades.

Body temperature

The range should represent resistor-element temperature, including ambient, self-heating, and nearby heat sources.

Recommended workflow

1Enter the nominal value, initial tolerance, and absolute TCR limit from the datasheet.
2Enter the reference temperature and both realistic operating-temperature endpoints.
3Use the min/max range in the error budget, then add the required load, ageing, and assembly shifts.

Checkable example

For 10 kΩ ±1%, ±100 ppm/°C, from −40 to +85°C with a 25°C reference, the largest thermal offset is 65°C. TCR adds ±0.65%, giving ±1.65% total: 9.835 kΩ to 10.165 kΩ.

What the envelope does not include

The TCR model is linear and does not include curve non-linearity, voltage coefficient, humidity, soldering shift, load-life drift, or ageing. Also verify power, maximum voltage, and thermal derating.

Frequently asked questions

Why add errors instead of using root-sum-square?

A min/max limit seeks the deterministic worst case: both errors can have the same sign. Root-sum-square is a statistical estimate that requires distribution and independence assumptions.

Is ambient temperature enough?

Not always. Dissipated power can raise component temperature materially. Use a body or element temperature estimate when self-heating is significant.

References to consult

IEC 60115-1:2020, generic specification and temperature-coefficient test method for fixed resistors.
Vishay technical guides covering tolerance, TCR, and non-linearity of the resistance-temperature characteristic.

Original educational content, reviewed for technical clarity on 11 September 2026. Always verify datasheets, applicable standards, and your design before power-up or manufacture.