# Lyestone — Soap lye calculator

> Soap lye calculator (iPhone/iPad app by Robert Corbin.)

- Source: https://appshunter.io/ios/app/lyestone/id6777543152 (this page in markdown: same URL + `.md`)
- Developer: [Robert Corbin](https://appshunter.io/developer/1890247992)
- Category: Utilities, Education
- Price: $2.99
- Age rating: 4+
- Requires: iOS 17.0 · 3 MB
- Languages: American English
- Released: 2026-06-10
- Data updated: 2026-08-13
- User reviews in markdown: https://appshunter.io/ios/app/lyestone/id6777543152/reviews.md

## What is Lyestone?

Lyestone is a soap maker's lye calculator that lives on your phone, not behind a paywall and a slow website.

Pick the fats in your recipe and enter their grams. Set your superfat and water. Lyestone computes - in real time, as you slide - the exact grams of sodium hydroxide (NaOH) for a bar soap, or potassium hydroxide (KOH) for a liquid soap. Same recipe, both lye types, one tap to switch.

WHAT'S BUNDLED

• 43 saponifiable fats, ready out of the box - olive, coconut (76 and 92 degree), palm, palm kernel, lard, tallow, castor, shea, cocoa butter, mango butter, kokum, hemp, sweet almond, avocado, jojoba (treated correctly as a wax), babassu, sunflower, rice bran, sesame, neem, soybean, peanut, walnut, hazelnut, apricot kernel, grapeseed, evening primrose, argan, abyssinian, tamanu, meadowfoam, andiroba, rosehip, borage, pumpkin seed, marula, baobab, camelina, perilla, poppy seed, pomegranate, and beeswax.

• SAP values for both NaOH and KOH, cross-checked against canonical references (SoapCalc, ModernSoapmaking.com, the Handcrafted Soap & Cosmetic Guild table).

• Per-recipe quality scores - hardness, cleansing, conditioning, bubbly, creamy - with a visible target band so you can tell at a glance whether your recipe is balanced.

• Iodine value (DOS risk) and INS, the two most-cited stability numbers.

• Quality warnings drawn from the literature: low conditioning, high cleansing, coconut-group dominance, wax-trace acceleration, KOH-superfat advisories, and more. Lyestone will tell you why your recipe is going to dry skin - before you pour it.

PROFESSIONAL FEATURES

• Lye concentration mode (master-batchers, soap-soaping by-the-spreadsheet types) - pin lye as a percentage of total solution instead of water-as-percentage-of-oils. 33% is one tap away.

• Fragrance load in oz/lb of oils → grams. Salt addition. Milk-soap flag with a reminder to freeze the milk.

• Markdown / CSV share - drop the calculation into your woodshop notebook, Reminders, or Messages with a single tap.

• Per-fat detail cards: SAP values, contribution scores, iodine, INS, plus a one-line note on how the fat behaves in a bar.

DESIGN PROMISE

No accounts. No analytics. No internet. No ads. Lyestone is a one-time $0.99 purchase - no subscriptions, no tiers, no unlocks. The app works the same on your phone, your iPad on the workbench, and the iPad locked in the woodshop.

SAFETY

Sodium and potassium hydroxide are highly caustic. Always wear gloves and goggles. Add lye to water (not water to lye). Lyestone is a hobbyist reference - consult primary sources and a soap-making mentor before scaling production.


## Version history (last 5 releases)

### 2.0.1 — 2026-06-26

This update sharpens the interface: the iPad layout now uses a centered, comfortable reading width instead of stretching edge to edge, plus small display fixes. iPhone is unchanged.

### 2.0 — 2026-06-21

Lyestone 2.0 — a pro upgrade from a lye number to a full recipe formulator, still 100% offline.

• Fatty-Acid Lab: real 8-acid profiles for all 43 fats, so your soap's Hardness, Cleansing, Conditioning, Bubbly, Creamy, Iodine, and INS are computed from actual chemistry — with a "who brings what" breakdown and a saturated/unsaturated split.
• Additive calculator: citric acid with exact extra-lye compensation, plus sodium lactate, salt, clays, titanium dioxide, mica, and more in grams and teaspoons.
• "Same water three ways": water-as-%-of-oils, lye concentration, and water:lye ratio that interconvert.
• PDF recipe sheet export and an INCI ingredient-label generator (Sodium Olivate, and so on).

All chemistry is computed on-device and oracle-verified. No account, no network — everything stays on your device.

### 1.2 — 2026-06-15

Lyestone 1.2 - two features that were missing from every other lye calculator.

BATCH COST BREAKDOWN
Enter what you paid for each fat - per ounce, per pound, per kilogram, or per gram - and Lyestone calculates total batch cost, cost per bar, and a line-by-line ingredient breakdown in real time. Price your lye too, if you want the full picture. Prices are saved per ingredient and carry over to every recipe automatically. Share the full breakdown as plain text from the sheet.

SCENT ADVISOR
A 33-entry essential oil reference built for cold-process soap. For each scent, Lyestone shows the maximum recommended grams for your current oil weight, trace-speed rating (slow / moderate / accelerates / seizes fast), scent retention in cured soap (poor / moderate / good / excellent), safety notes where applicable, and actionable blending tips. Source: The Nerdy Farm Wife printable chart, cross-checked with Brambleberry and Lovin Soap Studio usage guides. Browse by category (Floral, Citrus, Herbal, Woodsy, Spice, Earthy, Fresh, Resinous) or search by name or scent profile.

ALSO IN 1.2
- Both new tools open from the recipe editor menu () so the oil weight from your current recipe is always in scope.
- Batch cost sheet includes a bar-weight slider with one-tap presets (2.5 oz / 3 oz / 3.5 oz / 4 oz / 5 oz).
- Lye pricing toggle in the cost sheet is off by default - opt in only if you track NaOH / KOH cost.

### 1.1 — 2026-06-14

Lyestone 1.1 — three new features for makers who pour batches, not just calculate them.

MOLD CALCULATOR
Pick your mold shape (rectangular loaf, round cylinder, slab, individual cavities, or custom volume), enter its dimensions, and Lyestone tells you exactly how many grams of oils you need to fill it. Then choose any saved recipe and it scales every fat proportionally — one tap loads the scaled recipe straight into the editor.

BATCH JOURNAL
Log each batch you pour: which recipe, the actual oil weight, and the pour date. Lyestone shows a live cure progress bar, the minimum ready date (NaOH bar soap: 28 days; KOH liquid soap: 14 days), and the recommended ready date (42 days / 21 days). Cure timelines are based on published soap-making references. Delete a log at any time — everything stays on your device.

STARTER RECIPE LIBRARY
Ten well-known community recipes are now bundled — Classic Castile, Marseille 72, Bastille Bar, Heritage Tallow & Lard, Luxury Face Bar, Coconut Shampoo Bar, Sea Salt Bar, Liquid Soap Paste, Goat Milk Bar, and Cocoa Butter Luxury Bar. Tap any starter to preview its calculated numbers, then load it into the editor as your starting point.

ALSO IN 1.1
• "Load into editor" button now works on saved recipe detail cards (was visually implied but missing — fixed).
• New Batches tab in the bottom navigation.
• Starter Recipes and Mold Calculator are one tap from the recipe editor menu (⋯).

### 1.0 — 2026-06-10

No release notes.

## More apps by Robert Corbin

- [Daily Word Journey](https://appshunter.io/ios/app/daily-word-journey/id6761548266)
- [Hush Secret Text](https://appshunter.io/ios/app/hush-secret-text/id6761658175)
- [Renew Guard](https://appshunter.io/ios/app/renew-guard/id6761755447)
- [Receipt to PDF](https://appshunter.io/ios/app/receipt-to-pdf/id6761782025)
- [Route Your Pay](https://appshunter.io/ios/app/route-your-pay/id6761783719)
- [Tip Arbiter](https://appshunter.io/ios/app/tip-arbiter/id6761786879)

All apps by Robert Corbin: https://appshunter.io/developer/1890247992

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-13.*