Free engineering calculators for cGMP, hygienic and high-purity process systems. Each is built on the dimensional and design standards that actually govern sanitary equipment rather than on generic tables, and each shows its formulas and assumptions so the result can be checked and defended in a design review.
Sizing and volume
Pipe and Tube Volume Calculator
Internal volume, wetted surface area and flow velocity for hygienic tube and NPS pipe, on ASME BPE and ASTM A270 dimensions. It does not make the 33% error a generic pipe calculator makes on sanitary tube, and it reports the flow each size needs to reach the 5 ft/s CIP minimum.
Tank and Vessel Volume Calculator
Calculates the working and total volume of a vertical or horizontal cylindrical vessel including its heads, which matters because head geometry contributes meaningful volume a simple cylinder calculation misses. Use it to check that a proposed vessel holds the batch you need at a level the agitator can still mix, since minimum mixing level frequently constrains a design more than nominal capacity does. Confirm against the manufacturer certified volume before ordering.
Cleaning and cleanrooms
CIP Chemical Charge Calculator
Works out the quantity of cleaning chemical needed to reach a target concentration in a given circuit volume, including the hold-up in supply and return lines rather than the tank alone. That distinction is the common error: charging to tank volume alone leaves the circulating solution below target once the lines fill, which is a frequent cause of a cleaning cycle that under-performs without anyone changing the recipe.
Cleanroom Air Change Rate and HEPA Calculator
Converts between room volume, air change rate and required airflow, and sizes HEPA filter area to deliver it. Use it to test whether a proposed air change rate is affordable before committing, since ISO 14644 sets particle limits rather than an air change rate and the difference between 40 and 60 changes per hour in an ISO 7 room is roughly half the annual fan energy for the life of the room.
Surface and materials
Surface Roughness Converter (Ra, RMS, Rz, Grit)
Converts between the surface roughness units used across different specifications: Ra in microinches or micrometers, RMS, Rz, and abrasive grit designations. It is useful because specifications frequently mix units, and an RMS value is numerically larger than the equivalent Ra for the same surface. Grit conversions are approximate by nature, since grit describes an abrasive rather than a measured result.
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Why these are built differently
Most online process calculators return a number with no statement of what it assumes. That is fine for a rough check and dangerous in a design review, because the assumption is usually where the error lives – a nominal size treated as an internal diameter, an air change rate treated as a regulatory requirement, a geometric capacity treated as a working volume, a clean-filter rating treated as a lifetime value. Every calculator here shows its formula, names the standard its dimensions come from, and states plainly where it stops being valid.
They are also deliberately connected. A CIP charge depends on a circuit volume, and a circuit volume is a tank plus its pipework – so the tank and pipe calculators feed the CIP one. Where a figure is an approximation rather than an exact value, such as the ASME flanged and dished head coefficient, that is stated on the page rather than buried.
If you need the system these tools size actually designed, built, installed and qualified, that is what we do – see our services or request a quote.
New engineering tools
- Dead-leg L/D calculator — checks a branch against the ASME BPE limit of 2, and against the legacy six-diameter figure that is still widely quoted.
- CIP flow and velocity calculator — converts between pipe diameter, cleaning velocity and flow, and flags a circuit that will not reach turbulent velocity in its largest line.
- USP 645 conductivity and water spec lookup — the temperature-dependent Stage 1 limit, plus the full WFI and Purified Water specification set in one table.
See also our free browser-based tools for AI crawler access, non-JS crawler preview and llms.txt generation.