Engineering calculator

Conformity Decision Rule Calculator

Q: Is this the same as the Guard band page?

No. Guard band computes GB = k·u and optional acceptance limits. This page takes a measured y and returns pass or fail. Use Guard band to size w, then this page to decide.

Q: Is a result in the guard band conditional?

No. This contract is binary. If y is inside the specification but outside the acceptance interval, the decision is fail. It does not implement a three-way conditional statement from JCGM 106.

Q: Where does this run?

Locally in the browser by default. REST and MCP call the same metrology-engine conformity decision op.

Apply a binary ILAC G8-style decision to a measured value y: simple acceptance (w=0) or guarded acceptance (LSL+w ≤ y ≤ USL−w). Runs locally. Not JCGM 106 risk tables and not TUR.

Instant result

Result

—

Enter values to calculate.

Inputs—

Mode—

Formula—

Trust summary Engine tested · Source checked · 11/11 tests · Production surface contract 4/4 · v1.0.0

Input interpretation: Enter values to calculate.
Result: —
Model: Binary simple or guarded acceptance on a measured y.
Scope: ILAC G8-style binary simple (w=0) or guarded acceptance
Verification: Engine tested · 11/11 tests · Production surface contract 4/4 · Source checked · v1.0.0
Named expert review: Optional · Not performed
Sources: ILAC G8:09/2019 — Guidelines on Decision Rules and Statements of Conformity — 6.2 Simple acceptance and 6.3 Guarded acceptance (binary)
JCGM 106:2012 — The role of measurement uncertainty in conformity assessment — Risk-based and non-binary rules are a different contract
Sources
Evidence: 7 boundary · 4 property · Production surface contract 4/4 · Artifact integrity PASS
Production: Embedded snapshot: STALE · Last attested schema matched 1.0.0 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 164 CURRENT) @ 2026-09-16T06:44:24.909Z
Semantic contract: PASS

Formulas

Core equations used by this calculator.

SimpleLSL ≤ y ≤ USL

GuardedLSL + w ≤ y ≤ USL − w

iBinary pass/fail only. This page does not compute consumer/producer risk. Guard band computes GB without y. TUR is a ratio, not a decision.

How to use

Enter the measured value y

Same unit as the specification limits.

Enter LSL and/or USL

Two-sided when both are set (USL > LSL). One-sided when only one limit is present.

Choose simple or guarded

Simple uses w = 0. Guarded needs w or an already-expanded U (w = U). The band is fail, not conditional.

Example calculations

Common configurations with formula and result.

Simple pass

y=6 · LSL=0 · USL=12

0 ≤ 6 ≤ 12

pass

Guarded fail in the band

y=0.5 · LSL=0 · USL=12 · U=1

0.5 < 0+1

fail

Conformity Decision Rule calculator specification

Version 1.0.0 · Engine tested

Calculation status

Engine tested 11/11 tests · Production surface contract 4/4
Named expert review Not performed
Calculation version 1.0.0

Review policy · Evidence

Definition: Simple acceptance: pass if LSL ≤ y ≤ USL (w = 0). Guarded acceptance: pass if LSL+w ≤ y ≤ USL−w. The guard-band zone is fail. One-sided limits are allowed. Default rule is simple.
What it calculates: Binary simple or guarded acceptance on a measured y.
Inputs: y
lsl
usl
rule
w
U
Outputs: decision
rule
y
w
accept_lsl
accept_usl
Formula: simple: LSL ≤ y ≤ USL; guarded: LSL+w ≤ y ≤ USL−w
Assumptions: ILAC G8-style binary simple (w=0) or guarded acceptance
Default rule is simple
Guarded w from w or already-expanded U; the band is fail
Not JCGM 106 risk tables, not TUR, and not GB = k·u as a product
Units: same as y / LSL / USL; dimensionless decision
Boundary conditions: missing y or missing spec → MISSING_REQUIRED_INPUT
rule=guarded without w or U → MISSING_REQUIRED_INPUT
empty acceptance interval or unknown rule → INVALID_INPUT
Example: y=6 lsl=0 usl=12 rule=simple → pass
Validation cases: 2 published on this page · 11/11 tests · Production surface contract 4/4 · View evidence
y=6 lsl=0 usl=12 rule=simple → pass
y=0.5 lsl=0 usl=12 rule=guarded U=1 → fail
Sources: ILAC G8:09/2019 — Guidelines on Decision Rules and Statements of Conformity — 6.2 Simple acceptance and 6.3 Guarded acceptance (binary)
Supports: Simple: accept if y is inside the specification. Guarded: accept if y is inside the acceptance interval; the band is not a pass
JCGM 106:2012 — The role of measurement uncertainty in conformity assessment — Risk-based and non-binary rules are a different contract
Supports: This page does not compute specific consumer/producer risk or a conditional third outcome
Calculation version: 1.0.0

Background

Interpretation and common distinctions.

Apply a binary simple or guarded acceptance to a measured value.

Supported and not supported

Supported — simple (w=0) and guarded (w or U) on y · one-sided or two-sided limits · API engineering.conformity.decision_rule

Not supported — JCGM 106 risk tables, conditional third outcome, TUR≥4 verdict, GB = k·u as a product, RSS of u_i

Agent / API notes

Capability id: engineering.conformity.decision_rule · tool id: decision-rule · pin 1.0.0.

{ "y": 6, "lsl": 0, "usl": 12, "rule": "simple" }

rule defaults to simple. Guarded needs w or U. Errors: MISSING_REQUIRED_INPUT, INVALID_NUMBER, VALUE_MUST_BE_POSITIVE, INVALID_INPUT.

Calculator URL stays /calc/engineering/decision-rule. There is no /calc/metrology.

Other calculators in this family: Guard band, Test uncertainty ratio TUR, Maximum permissible error MPE, Normalized error En, Coverage factor k, Process capability (Cp/Cpk), Uncertainty propagate, Tolerance / Uncertainty Workspace .

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Frequently asked questions

Key distinctions behind the calculation.

Is this the same as the Guard band page?