Quality Management Tools

SPC CALCULATOR

Statistical Process Control for Analytical Chemistry and Quality Assurance

Real-time Control Charts Process Capability Analysis Quality Monitoring

DATA ENTRY

Import data, paste spreadsheet values, or enter measurements manually

LSL:
USL:
Subgroup Size: 2
S.G.X1X2
1
2
3
4
5

Control Limits & Statistical Parameters

X-Bar (Average) Limits

Center (CL) 0.000
Upper (UCL) 0.000
Lower (LCL) 0.000

Range (R) Limits

Center (CL) 0.000
Upper (UCL) 0.000
Lower (LCL) 0.000

CALCULATED PARAMETERS (N=2)

Grand Avg (X̄̄) 0.000
Avg Range (R̄) 0.000
Constant A2 1.880
Constants D3/D4
0.000 / 3.267

Detection Rules

In Control
X-Bar Chart
Rule 1: Beyond ±3σ (out of control)
Rule 2: 9 consecutive same side of CL
Rule 3: 6 consecutive trending
Rule 4: 14 alternating up/down
Rule 5: 2 of 3 beyond ±2σ (same side)
Rule 6: 4 of 5 beyond ±1σ
Rule 7: 15 within ±1σ (hugging)
Rule 8: 8 outside ±1σ on both sides
R Chart (Rules 1–4 recommended)
Rule 1: Beyond ±3σ (out of control)
Rule 2: 9 consecutive same side of CL
Rule 3: 6 consecutive trending
Rule 4: 14 alternating up/down
Out of control (R1) Run / trend (R2–4) Zone violation (R5–6) Stratification (R7–8) In control

CALCULATED DATA TABLE

SubgroupX1X-BARRANGE (R)
No data available

AVERAGE (X-BAR) CHART

RANGE (R) CHART

Process Capability Analysis

NEEDS SPECS

Short-Term Capability (Potential)

Cp (Spread) 0.000
Cpk (Centering) 0.000

Calculated using within-subgroup standard deviation (σ_ST). Represents the process potential if perfectly centered.

Long-Term Capability (Performance)

Pp (Spread) 0.000
Ppk (Centering) 0.000

Calculated using overall standard deviation (σ_LT). Represents the actual process performance over time.

STANDARD DEVIATIONS & COUNTS

WITHIN-SUBGROUP (σ_ST) 0.000
OVERALL DATA (σ_LT) 0.000
DATA POINTS (N) 0

DISTRIBUTION