Set target dimensions, choose tolerance style, and enter measured results quickly here. Instantly see pass or fail, capability indices, and printable records for audits.
Example checks for a 100 mm target with ±2 mm tolerance.
| Item | Target (mm) | Tolerance (mm) | LSL (mm) | USL (mm) | Measured (mm) | Deviation (mm) | Status |
|---|---|---|---|---|---|---|---|
| 1 | 100 | ±2 | 98 | 102 | 101.3 | 1.3 | PASS |
| 2 | 100 | ±2 | 98 | 102 | 98.9 | -1.1 | PASS |
| 3 | 100 | ±2 | 98 | 102 | 102.1 | 2.1 | FAIL |
| 4 | 100 | ±2 | 98 | 102 | 99.7 | -0.3 | PASS |
| 5 | 100 | ±2 | 98 | 102 | 97.8 | -2.2 | FAIL |
If you choose percent tolerance, the calculator converts it to absolute using |Target| × (Percent/100).
Accurate tolerances build trust, reduce rework, and speed approvals.
Construction work is built from many small dimensional decisions. When a slab edge, anchor bolt, or duct opening drifts from its target, downstream trades lose time on rework. A tolerance band sets a measurable acceptance rule so inspectors and crews act consistently. This calculator turns drawings into clear limits and immediate pass or fail results.
The core data is simple: Target, plus an upper allowance and a lower allowance. For a 100.0 mm target with ±2.0 mm, the limits become LSL = 98.0 mm and USL = 102.0 mm. If you use percent tolerance, the allowances scale with the target, helping when the same rule applies across multiple sizes.
Each measured value is compared to the limits, and the deviation is calculated as Measured − Target. Example readings 101.3, 98.9, and 102.1 mm produce deviations of +1.3, −1.1, and +2.1 mm. The first two are within limits, while 102.1 mm exceeds the USL and flags a failure for action.
With a list of readings, the tool reports mean, range, and sample sigma. If you provide a known sigma, it also computes Cp and Cpk to summarize process capability. As a practical guide, Cp or Cpk near 1.0 suggests the process barely fits the specification, while higher values usually indicate more stable control under the same limits.
QC records are only useful when they are easy to share. Exporting CSV supports daily logs and trend checks, while the PDF output provides a simple attachment for inspections. Use consistent rounding, keep units aligned with drawings, and record the tolerance basis to avoid misunderstandings during reviews.
A symmetric tolerance applies the same allowance above and below the target. For example, ±2 mm means the acceptable band is Target − 2 to Target + 2 in the same unit.
Use separate values when the specification allows different limits, such as +3 mm and −1 mm. This is common when one direction is functionally critical or constrained.
Percent tolerance converts the allowance using |Target| × (Percent/100). A 2% tolerance on a 100 mm target becomes ±2 mm. It scales automatically for other targets.
Cp and Cpk require a sigma value. If you enter only one measurement, sample sigma cannot be computed. Use a measurement list or provide a sigma override to enable capability results.
Use a sigma from your QC plan or historical process data for the same activity, crew, and method. A stable dataset from recent work is better than a guess.
More readings improve confidence. For quick checks, 5–10 points can show spread and drift. For capability studies, larger samples are preferred, especially across shifts or batches.
Yes. You can use units like MPa, psi, or °C for strength, pressure, or temperature checks, as long as your target and tolerances are defined consistently in the same unit.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.