SoapDIY-Soap Recipe Calculator

The best calculator for making handmade soap. Enter your oil recipe and instantly get the lye, water, and quality metrics you need.

Key features • Instant saponification: solid soap (NaOH) and liquid soap (KOH), by ratio or weight • Correct superfat: automatically applied to the lye amount (fixes a common mistake) • Flexible water settings: lye concentration / water-to-lye ratio / % of oils, default 33% • KOH purity: liquid soap auto-converts to the real amount by purity (default 90%) • Quality radar: hardness, cleansing, conditioning, bubbly, creamy — with recommended ranges • 59 built-in oils with verified SAP and fatty-acid data • Custom oils: add your own oils and fatty-acid profiles • Recipe management: save, search, share, export to PDF • Batch log: record each batch with photos and get an automatic cure reminder • Dark mode, Dynamic Type, and an iPad two-column layout

Safety Wear goggles and gloves and keep the area ventilated when handling sodium/potassium hydroxide. This app is for calculation reference; always follow proper safety procedures.