Manufacturing and Inventory Calculators

Every calculator on the site, grouped by the job. Each one shows the formula and the steps with your numbers, keeps its inputs in the link so you can share or repeat a result, and prints a dated record. Nothing you type is uploaded.

Production

• OEE calculator — availability, performance, quality and OEE with the losses in minutes.
• Takt time calculator — takt time from available time and demand, and the stations needed.
• Cycle time calculator — average cycle time, bottleneck step and Little’s Law lead time.
• Lead time calculator — total lead time from stages or past orders, delivery date and reorder point.
• MTBF calculator — mean time between failures, MTTR, availability, failure rate and FIT.

Quality

• Cpk calculator — Cp, Cpk, Pp and Ppk from summary statistics or raw data, with a histogram.
• Six sigma calculator — DPMO, yield and sigma level, and sigma level to DPMO.
• Gage R&R calculator — repeatability, reproducibility, %GRR and ndc by ANOVA or average and range.
• First pass yield calculator — first pass yield and rolled throughput yield of a process.
• Control chart generator — I-MR, X̄-R, X̄-s, p, np, c and u charts with control limits and rule signals.
• Pareto chart maker — sorted Pareto chart with cumulative % and the vital few.
• Histogram maker — histogram and frequency table with spec limits and a normal curve.
• Run chart maker — run chart with the median line, shift and trend rules, runs and crossings.
• Z score table — normal areas from z, z from a percentile, and the printable z table.
• CUSUM chart maker — tabular CUSUM with the first signal point and the new mean.
• Fishbone diagram maker — Ishikawa cause-and-effect diagram you can download as SVG.
• FMEA template and RPN calculator — failure modes ranked by RPN, with a CSV download.

Inventory

• Inventory turnover calculator — inventory turnover ratio and days of inventory.
• EOQ calculator — economic order quantity, annual costs and reorder point.
• Safety stock calculator — safety stock by four methods and the reorder point.
• Kanban calculator — the number of kanban cards for demand, lead time and container size.

Results are calculated from the values you enter; check them against your own process data before acting on them. You may use the results in commercial work.