How to Use a Soap Calculator

SoapMetrics helps you formulate, analyze, scale, and document handmade soap recipes. As you build a recipe, calculations update to show lye and water requirements, batch totals, soap quality metrics, fatty acid composition, warnings, and export options.

1. 1Click the recipe name at the top to name your batch.
2. 2Open the Soap Calculator tab and set Unit System, Weight Unit, Soap Making Process, and Scale Recipe (total oil weight).
3. 3Configure Lye Type, Lye Purity, Water Calculation Method, Superfat Method, and Superfat %.
4. 4Add fragrance if used; add additives (clays, sodium lactate, etc.) via Add Additive.
5. 5Add each oil with Add Oil; search the ingredient catalog and choose a specific variant when Choose variant appears; enter weight or percent for each row until oils total 100%.
6. 6Add Recipe Notes for anything not captured in fields.
7. 7Review the Recipe Ingredients sidebar and Soap Quality Metrics. Select ? or Why? beside metrics to understand estimate coverage.
8. 8If an older saved recipe shows Update ingredient information, use Review update before exporting or starting a batch.
9. 9Check warnings, coverage notes, and Special Ingredient Notifications on the Soap Analysis tab, run Compliance Check (Premium) if you need ingredient restrictions verified, then save, export PDF, or generate Full Recipe Instructions (Premium).
10. 10Open Soap Cost Calculator (Premium) from the Cost Calculator tab to price the oils, lye, fragrance, and additives in this recipe from what you actually paid, then enter bars produced for invested cost per bar.
11. 11Open Ask SoapMetrics (Premium) to ask recipe-aware questions about the formula currently loaded. Treat replies as assistance and double-check them before making soap.
12. 12When you make the recipe, start a batch from Batch Tracking (Premium). After it is a Completed Batch, use Add to Inventory to track finished bars.

The calculator has main tabs plus a recipe summary sidebar:

Recipe header

Shows the recipe name (click to rename), Reset Form to start over, and Dashboard (Premium) to open saved recipes, Completed Batches, and Inventory.

Soap Calculator tab

Main formulation area: settings, lye, fragrance, additives, oils, and notes—top to bottom.

Soap Analysis tab

Advanced charts: saturation profile, iodine/INS analysis, pH estimate (not a measured cured-soap pH), fatty acid pie chart, estimate coverage captions, Special Ingredient Notifications, and formulation warnings/tips.

Compliance Check tab

Premium ingredient and soap-style review. Select criteria such as vegan, palm-free, or fragrance-free and SoapMetrics flags conflicts in your current recipe.

Soap Cost Calculator

Premium recipe costing, opened from the Cost Calculator tab. Oils, lye, fragrance, additives, colorants, and toppings with quantities import from the current recipe. Enter what you paid so SoapMetrics can calculate batch cost and invested cost per bar. Distilled water is excluded by default. This is separate from Inventory.

Batch Tracking tab

Premium production management linked to the calculator recipe—lot numbers, timeline, cure progress, notes, photos, email reminders, and Add to Inventory when a batch is marked Completed Batch.

Recipe Ingredients sidebar

Sticky summary on the right (desktop) showing calculated lye, water, oils, additives, totals, and export buttons including Start Batch from Recipe (Premium).

Bottom action bar

Save Recipe, Export PDF, and Start Batch from Recipe (Premium) depending on tab and subscription status.

Unit System

Metric (g, kg) or Imperial (oz, lb). Controls which weight units appear throughout the calculator.

Weight Unit

Working unit for oils and calculated amounts—grams, kilograms, ounces, or pounds.

Soap Making Process

Cold Process (CP) — oils and lye are combined, poured into a mold, and cure over weeks.
Hot Process (HP) — soap is cooked to accelerate saponification. HP defaults to post-cook superfat method when selected.

Scale Recipe

Total oil weight for the batch—the combined weight of base oils, fats, waxes on the Oils & Fats route, and butters only (not finished soap weight). Example: 16 oz olive + 8 oz coconut + 4 oz shea = 28 oz total oil weight. For each oil row, enter weight or percent; SoapMetrics updates the other from this total.

Lye Purity

Enter your supplier's alkali purity as a percentage—for example 100, 99, 98, 90, or a decimal such as 98.5. Changing purity adjusts only the active-alkali calculation; it does not switch between NaOH and KOH. When you change Lye Type, SoapMetrics keeps the current purity value—including intentionally entered 100% or 90%—and asks you to review that it matches the alkali you selected. Dual-lye recipes use separate NaOH and KOH purity fields.

Water Calculation Methods

Superfat

Lye Discount (Standard)

Reduces calculated lye so a percentage of oil remains unsaponified. Typical body soap: 3–8%.

Post-Cook Addition (HP)

Lye is calculated on oils saponified during the cook; selected oils are added after cooking. Configure base superfat for cooking, then add post-cook superfat oil(s) with amount by % or weight.

Effective Superfat

Displayed when using post-cook method—combines base superfat and post-cook oil addition.

Click Add Fragrance to add a row. Choose Fragrance Oil (FO) or Essential Oil (EO), input method, load, and name.

Input Method

Percentage of oils — fragrance as % of total oil weight.
Oz per lb of oils — common industry method (e.g., 0.5 oz/lb).

Fragrance Load

The rate or amount entered according to your input method.

Fragrance Name

Product or blend name for saved recipes and exports.

Use Add Additive in the Additives section for each powder, liquid, or specialty ingredient. Select the additive from the database, choose an input method (tsp, tbsp, % of oils, grams, etc.), and enter the amount.

Click Add Oil, search the ingredient catalog, and enter Weight or Percent for each row. Changing one updates the other based on Scale Recipe (total oil weight).

Normalize Recipe

Proportionally adjusts oil percentages to total 100%. Review results before continuing.

Total Percentage

Shown below the oil list. A percentage-based formula should total 100%.

Ingredient data

Each catalog entry includes the properties documented for that ingredient. SAP values support lye calculations independently. Quality estimates, fatty acids, iodine, and INS use the applicable documented model for that ingredient—partial or non-applicable models do not force unavailable data to zero. Select ? or Why? beside a metric for coverage details.

Use the Recipe Notes field for batch dates, color plans, temperatures, trace behavior, mold used, cure observations, substitutions, and ideas for the next batch. Notes appear in PDF exports and premium instruction documents when saved.

The sidebar summarizes your running recipe. Review these before touching lye:

The Soap Analysis tab includes:

• Saturation profile (saturated vs unsaturated fats and sat:unsat ratio)
• Advanced iodine and INS analysis with stability guidance
• pH estimate and alkali risk assessment with testing guidance—an estimate is not a measured finished-soap pH or proof that excess alkali is absent
• Fatty acid pie chart (HP-aware phases when applicable)
• Soap quality bar chart with ideal-range comparison
• Formulation warnings and tips
• Special Ingredient Notifications when the recipe includes items that can change heat, trace, or handling

Where the notices appear

Soap Analysis banner

A yellow Special Ingredient Notifications box appears at the top of the Soap Analysis tab when one or more matching ingredients are in the recipe. Click View Alerts to continue.

Soap Tips

Premium users are taken to Soap Tips with Analyze Recipe expanded. Ingredient alerts stay at the top, labeled as Ingredient Alerts. Use More Info for the longer explanation. These tips do not have a Fix button because they are ingredient-based, not formula-balance issues.

Free accounts

Free users still see the yellow banner so they know special handling may apply. View Alerts opens the Get Premium modal. Full alert details, Soap Tips expansion, and step-by-step placement are Premium features.

Estimate coverage notes

Separate from process alerts, SoapMetrics may show model-coverage information when an ingredient supports lye but not every quality estimate. Free accounts see generic guidance; Premium users can open ingredient-specific tips in Soap Tips. Basic Export PDF includes a general coverage note; Premium exports and Full Recipe Instructions can include more detail. Coverage Why? explains the estimate—it is not the same as the Premium paywall on View Alerts.

Exports and Full Recipe Instructions

Free signed-in Export PDF includes a general yellow notice that special ingredients can change the process. Premium Export PDF and Full Recipe Instructions show the full alert details and place handling in the correct making steps—such as adding salt last, dispersing clay before it goes into the batter, or stirring sodium lactate into cooled lye.

How to use Compliance Check

1. 1Build or load a complete recipe in the calculator (oils, additives, fragrance as applicable).
2. 2Open the Compliance Check tab.
3. 3Use the search box to find criteria, or expand accordion groups such as Dietary & Lifestyle, Ingredient Restrictions, Fragrance & Scent, Skin Profile, Soap Style & Specialty, and Marketing & Certification.
4. 4Check the criteria that apply to the soap you intend to make or sell.
5. 5Review the Recipe Snapshot summary, then read each result card.
6. 6Click status badges (Pass, Fail, Review, Verify, Info) to filter results.
7. 7Open Details on any finding for ingredient context, amount, and criteria explanation.
8. 8Use Analyze Ingredients for a full classified ingredient list with tags.
9. 9Export Compliance PDF when you want a printable record for batch review or labeling prep.

Understanding result statuses

Pass

No conflicting ingredients were detected for this criteria based on available recipe data.

Fail

One or more ingredients appear to conflict with the selected criteria (for example, tallow in a vegan check).

Review

Possible concern—double-check supplier info, naming, or amount before proceeding.

Verify

SoapMetrics cannot confirm this automatically. You must verify certification, sourcing, or supplier claims.

Info

Informational guidance about the recipe profile (for example, castile-style or high-lather characteristics).

Example criteria categories

Recipe amounts import automatically for oils and fats (including post-cook superfat), NaOH and KOH, fragrance, additives, colorants, and toppings that have quantities. Distilled water is excluded unless you choose to include it.

How to use Soap Cost Calculator

1. 1Build or load a complete recipe in Soap Calculator so oils, lye, fragrance, and additives have amounts.
2. 2Open the Cost Calculator tab.
3. 3Each listed ingredient shows Recipe uses with a blank Purchased qty, Purchase unit, and Price paid.
4. 4Enter what you bought (for example 100 oz of olive oil for $22.99). SoapMetrics calculates the share this recipe consumed.
5. 5Set Currency if you price in GBP, AUD, or another listed currency. Amounts stay in the currency you type—SoapMetrics does not convert exchange rates.
6. 6Enter Actual bars produced to see invested cost per bar.
7. 7Open Optional additional costs to add labels, wrapping, boxes, labor, or a custom cost for this batch.
8. 8Use Remember these ingredient prices or Save Cost Snapshot if you want the same purchase details reused on later recipes.

What counts toward cost

Use it for professional-style assistance on trace, lather, softness, additives, and formulation direction. It does not recalculate lye, change weights, or replace the calculator. For a full overview and disclaimer, see the Ask SoapMetrics page.

How to use Ask SoapMetrics

1. 1Build or load a complete recipe in Soap Calculator so oils, lye, water, fragrance, and additives are current.
2. 2Open the Ask SoapMetrics tab.
3. 3Start a new chat, or open a previous chat from the list if you want to continue one. Chats are listed by recipe name, and you can search the list.
4. 4Type a question about this recipe, or choose an example prompt such as why the recipe might trace quickly.
5. 5Read the reply against the calculator numbers. If they disagree, trust the calculator and investigate.
6. 6Use Export Chat to save the conversation as a PDF with the recipe name, date, and a double-check disclaimer.
7. 7On larger screens, collapse Previous chats if you want a wider chat window.
8. 8Delete an old chat with the trash icon when you no longer need it.

What it is good for

Starting a batch

You can start a batch from three places:

• The Start Batch from Recipe button on the Batch Tracking tab
• The Start Batch from Recipe button in the Recipe Ingredients sidebar (below Export PDF)
• The Start Batch from Recipe button in the bottom action bar (below the calculator tabs)

All three open the same start dialog with your current calculator recipe pre-filled. Confirm batch name, process type, made date, expected bars, mold, cure days, and whether to create default email reminders.

Batch dashboard overview

Production timeline

Each batch moves through stages: Planned → Made → In Mold → Unmolded → Cut → Curing → Ready to Package → Ready → Completed Batch. Use Advance to next stage in the batch detail panel, or set status manually. Suggested milestone dates are calculated when you start a batch and can be edited at any time.

When a batch is completed

Marking a batch Completed Batch means production is finished. It then appears on the Dashboard Completed Batches tab. Completed Batch does not automatically add bars to inventory—you choose when to do that.

Open the completed batch and click Add to Inventory. SoapMetrics copies the finished bars into Inventory → Completed Bars, using the batch number, recipe name, bar count, and photos from the batch record. If that batch is already in Completed Bars, SoapMetrics tells you instead of creating a duplicate.

Batch detail tabs

Overview

Batch name, status, dates, linked recipe snapshot summary, mold, bar counts, and milestone schedule.

Production

Actual batch notes—temperatures, trace, mixing time, fragrance/additives used, and issue flags (acceleration, ricing, seizing, soda ash, cracking, and more).

Cure

Cure progress bar (for example, Day 12 of 42), cure log entries with bar weight and observations during cure.

Quality

End-of-batch scorecard: appearance, scent, hardness, lather, conditioning, longevity, color, overall rating, and whether you would make the exact formula again. Create Revised Recipe loads a copy into the calculator without altering the saved batch snapshot.

Photos

Store multiple batch photos (after pour, unmold, cut, cure, finished bar) as reference URLs or notes.

Business

Optional supplier/lot tracking, batch and per-bar cost, packaging, and sales counts for makers who sell soap.

Inventory Ingredients

Optional accordion on the batch: match recipe oils and additives to inventory items, then confirm to deduct stock. Opening the section does not change quantities. You can return previously deducted amounts if needed. Portions you mark as manual are not taken from inventory.

Email reminders

When starting a batch, you can enable default reminders for unmolding, cure check, and cure completion. Reminders are sent to the email on your SoapMetrics account. Override any scheduled date in the batch detail Overview tab.

Moving finished bars into inventory

1. 1Finish production and advance the batch to Completed Batch.
2. 2Open the batch from Batch Tracking or from Dashboard → Completed Batches.
3. 3Click Add to Inventory on the batch status card.
4. 4SoapMetrics creates an Inventory → Completed Bars record with the batch number, recipe name, bar quantity, and photos.
5. 5Later, open that Completed Bars row to lower quantity when bars are sold or given away, add photos, or archive the record.

Inventory is a ledger you maintain. SoapMetrics does not see your shelf. Update quantities when you receive a shipment, restock, apply ingredients to a batch, or sell finished bars.

Inventory tabs

Ingredients

Oils, butters, additives, and similar materials. Add items with quantity, unit, optional cost, supplier, and low-stock settings. Use Restock to add incoming stock. Archive hides an item from the active list without deleting history.

Supplies

Packaging and other production supplies tracked the same way as ingredients.

Molds

Loaf, cavity, and slab molds with optional dimensions, cavity count, number owned, and preferred fill weight. Archived molds are hidden from the active list.

Suppliers

Vendor records you can attach to inventory items, with optional export of the supplier list.

Completed Bars

Finished soap added from a Completed Batch. Search by name, batch number, or recipe. Click a row to edit quantity on hand, add a reason (for example sold at market), manage photos, or archive.

Stock Activity

History of restocks, adjustments, batch usage, supplier changes, and completed-bar quantity updates.

Using inventory with a batch

On a batch, open Inventory Ingredients to match calculator oils and additives to inventory items. Confirm before anything is deducted. If a recipe amount is larger than stock, you can take what you have from inventory and treat the rest as a manual portion. Return Ingredients to Inventory puts previously deducted amounts back.

Reviewing saved ingredient data

Older saved or imported recipes may preserve chemistry from when they were last saved. SoapMetrics does not silently overwrite that data when catalog definitions improve.

Update ingredient information

When saved chemistry differs from the current catalog, an informational card lists the affected ingredients. Click Review update to see what may change. Proposed lye appears only when the adopted values validate.

Update and recalculate

Confirms adoption of current ingredient data and recalculates lye. Your oil amounts, percentages, and other recipe settings stay the same unless you edit them.

Not now

Keeps the saved chemistry for now. Lye may stay withheld until you review the update. Exports and batch actions that require current calculations may ask you to resolve the prompt first.

Unresolved variants

Parent-selector rows still need an explicit variant choice. Adoption does not pick Sweet vs Sour Cherry or similar grades for you—resolve Choose variant before relying on calculations or exports.

Metrics use the applicable documented model for each ingredient in your blend. Reference ranges help compare to common formulation targets—they are guidelines, not pass/fail rules.

Hardness

Estimates contribution to a firm, durable bar.

Cleansing

Reflects fatty acids associated with stronger oil-removing properties.

Conditioning

Estimates oils associated with a milder, more conditioning feel.

Bubbly Lather

Estimates tendency toward larger, more active bubbles.

Creamy Lather

Estimates dense, stable, creamy lather characteristics.

Longevity

Composition proxy from palmitic + stearic (equivalently hardness minus cleansing). It is a formulation indicator, not a measured wear test.

Stability

Custom composition-based stability indicator derived from iodine, linoleic, and linolenic in your blend. It is a formulation proxy—not a measured shelf-life test or lather persistence measurement.

Iodine

Traditional value related to unsaturation in the oil blend.

INS

Traditional index from SAP and iodine-related values. Use as a reference, not a pass/fail score.

SoapMetrics combines each ingredient's documented fatty acids proportionally by recipe percentage when that ingredient supports fatty-acid estimates. Ingredients without a fatty-acid model are excluded from this chart—not counted as zero acids. Coverage can differ from iodine, INS, or bar-quality metrics; select ? or Why? beside related captions for details.

Lauric

Hardness, cleansing and bubbly lather.

Myristic

Hardness, cleansing and lather contribution.

Palmitic

Hardness, longevity and creamy lather.

Stearic

Hardness, longevity and dense creamy lather.

Ricinoleic

Lather support and stability; strongly associated with castor oil.

Oleic

Conditioning character and milder skin feel.

Linoleic

Conditioning and skin feel; highly unsaturated.

Linolenic

Conditioning and skin feel; more oxidation-prone at higher levels.

SoapMetrics may show messages when values fall outside common ranges or deserve attention:

Information

Something worth knowing; review if curious.

Caution / Warning

Review the setting before making the recipe.

Special Ingredient Notifications

Ingredient-based process alerts (Premium details). They explain handling changes and do not alter lye calculations.

Estimate coverage

Model-coverage notes explain which portion of your recipe supports a given estimate. They are separate from process alerts and from formula-balance Soap Tips.

Error

A structural issue such as oil percentages not totaling 100%.

Soap Tips and Analyze Recipe fixes

Fix preview

Shows how selected oil amounts or percentages would change before anything is applied. Review the previewed totals—especially oil percentages—before confirming.

Apply Verified Fix

Available when the targeted calculator rule clears after the previewed change. “Verified” means the specific SoapMetrics guideline for that tip is satisfied—not laboratory validation or a guarantee the recipe is ideal for your process.

Apply Change / Apply Improvement

Applies a previewed adjustment that improves the formula but may not fully clear the guideline, or involves a tradeoff between metrics.

Cancel

Closes the fix dialog without changing the recipe. Partial estimate coverage does not drive unsupported whole-recipe fixes—only tips with an applicable Fix path can be applied.

When the recipe includes special items such as salt, vinegar, honey, milk, or clay, the document adds a notice at the top and places the handling in the correct step (for example, salt last, or clay pre-dispersed). The document uses calculated lye, water, and ingredient amounts from SoapMetrics—not invented values.

• ✓Wear splash-resistant eye protection.
• ✓Wear chemical-resistant gloves and protective clothing.
• ✓Work in a controlled, ventilated area.
• ✓Keep children, pets, and bystanders away.
• ✓Use an accurate digital scale.
• ✓Use heat-safe, lye-compatible containers—never aluminum with NaOH/KOH.
• ✓Add lye slowly to measured liquid—never pour liquid onto dry lye.
• ✓Avoid breathing fumes from fresh lye solution.
• ✓Label and store lye securely.
• ✓Review the supplier Safety Data Sheet (SDS).
• ✓Do not neutralize lye on skin with vinegar; flush with water and seek medical help when needed.