Bath bomb ratio calculator — parts to grams for a batch
Set baking soda, citric acid, and optional other dry parts (default 2:1), enter total batch grams, and get each ingredient’s weight. Oils and scent stay separate.
Results
Baking soda: 200 g
Citric acid: 100 g
Other: 0 g
Formula
each = total × parts ÷ sum(parts)
Worked steps (check these)
- Σ = 2 + 1 + 0 = 3
- Baking soda = 300 × 2 ÷ Σ = 200 g
- Citric acid = 300 × 1 ÷ Σ = 100 g
Dry-mix estimate only — oils, color, and scent are separate. Test small batches; not a safety or regulatory check.
Bath bombs are mostly a dry ratio problem. Scale the batch without rewriting a recipe by hand.
How to use
- Enter batch total grams
- Set soda / citric / other parts
- Read each ingredient’s grams
Why this calculator
- Editable parts
- Grams for shopping
- Clear dry-mix scope
Good for
- Gift sets
- Market trays
- Recipe scaling
Tips
- Test a small mold first
- Store citric dry to avoid early fizz
Examples
| Input | Output | Note |
|---|---|---|
| 300 g total at 2:1 soda:citric | 200 g soda, 100 g citric | Add oils/color outside this dry split |
Bath bomb FAQ
- Why not a full soap lye calculator?
- Cold-process soap needs oil SAP tables and safety rules we deliberately skip. This page only splits dry bath-bomb parts.
- Can I change 2:1?
- Yes — edit soda and citric parts. Keep totals positive.
- Price the batch?
- Use Craft pricing after you know material cost.