What is the difference between a formula and a recipe in compounding?

In compounding, a formula (or master formula record) specifies every ingredient, its quantity per unit or per batch, the manufacturing procedure, quality checks, BUD and storage conditions. A recipe is an informal term for the same document. Regulatory bodies require a master formula record for each compounded preparation as part of quality assurance documentation.

⚗️

Compounding calculator

Free

Enter your base formula and batch sizes. The calculator scales each ingredient quantity proportionally and produces a printable compounding worksheet. Add up to 15 ingredients per formula.

Formula / preparation name

Formula reference / lot number

Base formula batch size

Target batch size to prepare

Ingredient name

Qty (base)

Unit

Compounding worksheet

Export:

Pharmaceutical compounding: scaling formulas accurately

Compounding is the preparation of a customised medication for an individual patient when a commercially available product doesn't meet their needs. Accurate formula scaling is critical, errors in ingredient quantities can lead to subtherapeutic, toxic or contaminated preparations.

Proportional scaling

Every ingredient quantity scales by the same factor: new quantity = original quantity × (target batch / base batch). For a 100g base formula scaled to 250g, every ingredient is multiplied by 2.5. This calculator handles the arithmetic for up to 15 ingredients simultaneously, reducing transcription errors.

Beyond-use dating (USP guidelines)

USP Chapter 795 (non-sterile) guidelines: non-aqueous preparations (creams, ointments, suppositories), up to 6 months BUD. Water-containing oral formulations, 14 days refrigerated. Topical/dermal aqueous preparations, 30 days. Sterile preparations follow USP 797 with much stricter requirements. Always verify current USP guidelines, which are updated periodically.

Documentation requirements

A compounding master formula record must include: preparation name and strength, ingredients and quantities, equipment, procedures, quality checks, BUD and storage. This calculator generates a worksheet that can form the basis of your compounding record, verify against your facility's requirements before use. Pair this with our Concentration Calculator for solution strength verification and the Pharmacy Unit Converter for ingredient unit conversions.

Frequently asked questions

How do I scale a compounding formula to a different batch size?

Multiply each ingredient quantity by the ratio of the new batch size to the original batch size. If the original formula makes 100g and you need 250g, multiply each ingredient by 2.5. This calculator automates that process for up to 15 ingredients simultaneously.

What is beyond-use date (BUD) in compounding?

Beyond-use date (BUD) is the date after which a compounded preparation should not be used. Unlike manufactured drugs, compounded preparations don't have expiry dates based on stability studies. BUDs are assigned based on USP guidelines: non-sterile preparations have BUDs of up to 6 months for non-aqueous and 14 days refrigerated for water-containing formulations.

What is a master formula record in compounding?

A master formula record specifies every ingredient and its quantity per batch, the manufacturing procedure, equipment, quality checks, BUD and storage conditions. Regulatory bodies require a master formula record for each compounded preparation as part of quality assurance documentation.