Is Cp 2.00 realistic?

For most legacy processes, no. It usually requires DFM, tooling investment, or fundamental design changes.

Capability Interpretation

Cp = 2.00: Six Sigma Potential

2 min read Last updated July 2026

Cp 2.00 means the natural process variation is exactly half of the tolerance — the original Motorola Six Sigma definition for potential capability.

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The engineering question this page answers

What must change in design or process technology to reach Cp 2.00, and when is chasing it worth the cost?

Decision logic

Is Cp 2.00 required by the CSR or risk class? If not → do not target it ↓ Is variation reducible with current technology? If no → design or technology change ↓ Confirm MSA can resolve the tighter variation before claiming Cp 2.00

Typical PPM and sigma equivalent

Typical PPM: ≈ 0.00198 PPM only if centered so Cpk also equals 2.00; do not apply a 1.5σ shift unless explicitly using that convention
Sigma equivalent: 6σ potential

Engineering procedure

Establish MSA capable of resolving the reduced variation (%TV under 10 typical).
Run a long-window Pp study to confirm the potential holds.
Document the process technology assumptions (closed-loop, in-process gauging, etc.).

Typical failure modes

Claiming Cp 2.00 with a gauge that cannot resolve the tighter distribution.

Engineering insight

Cp 2.00 usually requires halving the current σ; SPC tuning rarely achieves that alone.
If MSA is not capable enough, "measured" Cp 2.00 is dominated by measurement error, not process performance.

When NOT to use this metric

Non-critical characteristics; use lower targets and invest resources where risk demands.

Relationship to other capability metrics

Cp 2.00 corresponds to 6σ potential; Cpk 2.00 needs perfect centering.

Recommended actions

Use the free Process Capability Calculator to compute Cp, Cpk, Pp, Ppk, sigma level, and predicted PPM from your measurement data — no sign-up required.

Engineering notes

Do not confuse Cp 2.00 with the Six Sigma "3.4 DPMO" figure — that figure includes a 1.5σ shift.

Continue the investigation

For Six Sigma conversion, see Sigma Level to Cpk and Cpk = 2.00.

Verification checklist

MSA capable of resolving the tighter distribution
Long-window Pp confirms the potential
Sigma-shift convention disclosed

Assumptions and applicability

Process condition: statistical stability is required.
Distribution assumption: use a distribution model justified for the data.
Confirm process stability and measurement-system adequacy before interpreting a capability index.
Use a justified distribution model or non-normal method when the normal model is unsuitable.