Independent standard-component screen

Measurement uncertainty

Inputs

Measured valueyunitReported value used only to express the relative expanded uncertainty.

Type A standard componentuAunitUser-entered standard uncertainty component from a stated statistical evaluation.

Calibration standard componentuCalunitUser-entered standard uncertainty component; convert any stated interval before entering.

Resolution standard componentuResunitUser-entered standard uncertainty component for resolution or quantization.

Environmental standard componentuEnvunitUser-entered standard uncertainty component for the stated environmental influence.

Coverage factork—User-supplied multiplier only; this screen does not select k or assert coverage probability.

Combined standard uncertainty

0.054772

unit

Expanded uncertainty

0.10954

unit

Relative expanded uncertainty

0.43818

uc = √(uA² + uCal² + uRes² + uEnv²); U = k·uc

A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.

Calculation snapshot

Formula version 1.0.0

Measured value	25
Type A standard component	0.04
Calibration standard component	0.03
Resolution standard component	0.02
Environmental standard component	0.01
Coverage factor	2

Combined standard uncertainty	0.054772 unit
Expanded uncertainty	0.10954 unit
Relative expanded uncertainty	0.43818 %

uc = √(uA² + uCal² + uRes² + uEnv²) · U = k·uc

NIST Technical Note 1297: https://www.nist.gov/pml/nist-technical-note-1297

This printout is a record of displayed inputs and deterministic formula output. It is not an approval, certification, or engineering conclusion.

Method

Combine independent standard uncertainty components and report expanded uncertainty using a coverage factor.

uc = √(uA² + uCal² + uRes² + uEnv²); U = k·uc

When

Don’t

This is root-sum-square arithmetic for user-entered independent standard uncertainty components in compatible units. It does not select distributions, convert stated intervals to standard uncertainties, evaluate correlations or sensitivity coefficients, determine degrees of freedom, choose a coverage factor, assert coverage probability, or certify a result.