MACO Calculator (Cleaning Validation Carryover)
Compute the Maximum Allowable Carryover of a previous product into the next product on shared equipment. The tool runs the three standard criteria (dose, 10 ppm, and health-based) and reports the most stringent limit for cleaning validation planning.
Smallest therapeutic daily dose of the product being cleaned away, in mg.
Maximum daily dose of the following product made on the same line, in mg.
Smallest batch size of the next product. kg is converted to mg by multiplying by 1,000,000.
Default 1000 for oral solid dose, 100 for topical, 10000 for more critical routes such as parenteral.
Permitted Daily Exposure or Acceptable Daily Exposure, in mg per day. If provided, the health-based criterion is computed.
Total shared product-contact area. If provided, the limit per surface area is shown.
Result
Governing MACO (most stringent)
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Dose criterion
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10 ppm criterion
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Health-based criterion (PDE)
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Limit per surface area
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Governing MACO spread over the total shared area. Model your swab area separately in your protocol.
For planning only. This tool gives an indicative carryover limit to support scoping. It is not a cleaning validation. Actual acceptance limits must follow your validated cleaning protocol and health-based exposure limits (PDE or ADE derived by a qualified toxicologist), with recovery studies and analytical method validation for the sampling you use.
What MACO means and how it is calculated
MACO, the Maximum Allowable Carryover, is the largest amount of a previous product that may carry over into the next product manufactured on the same shared equipment without posing a risk to the patient. In cleaning validation you calculate MACO by several accepted criteria and then work to the smallest, most stringent result. The governing limit becomes the target your cleaning process and your analytical sampling must be able to demonstrate.
Dose criterion
MACO_dose = (TDD_prev x MBS_next) / (SF x MDD_next). It ensures that no more than a small fraction (set by the safety factor) of the smallest therapeutic dose of the previous product can appear in a maximum daily dose of the next product.
10 ppm criterion
MACO_ppm = 10 mg of previous product per kg of next product, times the minimum batch size of the next product in kg. It caps carryover at a general chemical limit that is independent of pharmacology.
Health-based criterion (PDE)
MACO_PDE = (PDE x MBS_next) / MDD_next. Modern guidance treats the health-based limit, driven by a Permitted Daily Exposure from a qualified toxicologist, as the primary criterion. Enter the PDE to include it.
MACO calculator: FAQ
What is MACO in cleaning validation?
MACO is the Maximum Allowable Carryover: the most previous product that may remain on shared equipment and pass into the next product without harming the patient. It is the acceptance limit your cleaning and sampling must meet.
What are the dose, 10 ppm, and health-based criteria?
The dose criterion limits carryover to a fraction of the smallest therapeutic dose. The 10 ppm criterion caps it at 10 mg of previous product per kg of next product. The health-based criterion uses a PDE or ADE from a toxicologist. You calculate each and take the smallest as the governing MACO.
What safety factor should I use?
A common convention is 1000 for oral solid dose products, 100 for topical products, and 10000 for more critical routes such as parenteral or ophthalmic. The exact factor should reflect your route of administration and your quality risk assessment, not a fixed rule.
Is this a substitute for a validation protocol?
No. This is a planning aid. A compliant approach needs health-based exposure limits set by a qualified toxicologist, a validated cleaning procedure, recovery studies, and a validated analytical method for your chosen sampling. Use the number here to scope the work, then follow your validated protocol.
Need a defensible cleaning validation programme?
We help pharmaceutical manufacturers set health-based exposure limits, build cleaning validation protocols, and pass GMP inspection. Turn an indicative MACO into a validated, audit-ready limit.