Can I enter stock strength in ppm or percent?
Yes. The calculator accepts either value and converts percent into ppm internally before calculating the dilution.
HOCl Stock to Add
200
mL
of HOCl stock for a 100 ppm working solution in 1,000 mL total volume using 500 ppm stock.
Use fresh batches
Store in opaque bottles
Verify with test strips
Mixture Breakdown
Batch math at a glance
HOCl Stock
200 mL
Water Amount
800 mL
Total Solution
1,000 mL
Dilution Ratio
1:4
Target Strength
100 ppm
Stock Strength
500 ppm
HOCl share of solution
20% HOCl
Safety Guidelines
Three rules that matter
- Keep it away from light and heat. HOCl loses strength quickly if it sits in clear containers or warm storage.
- Do not mix with incompatible cleaners. Follow the product label and never combine it with acids, ammonia, or other unknown chemicals.
- Verify ppm for critical uses. Food-contact or healthcare-related uses should be checked with test strips and the product label.
Formula Blueprint
How HOCl dilution math works
The calculator uses the standard C1V1 = C2V2 dilution identity. Stock strength can be entered in ppm or percent; percent values are converted to ppm before the math is solved.
Core Dilution Equation
C1 x V1 = C2 x V2
C1 is the stock HOCl concentration, V1 is the stock volume to add, C2 is the target ppm, and V2 is the total finished solution volume.
Stock Volume Solved
V1 = (C2 / C1) x V2
Divide the target ppm by the stock ppm, then multiply by the finished batch size. That gives the exact HOCl amount needed.
Water Volume
Vwater = V2 - V1
The water fills the rest of the batch. Add the stock solution to the water to keep the mix controlled and splashing down.
C1Stock concentration on your HOCl label, converted to ppm if needed
V1Volume of stock to add
C2Target finished concentration in ppm
V2Total finished solution volume
Reference Table
Common HOCl target presets
Rows are calculated against your current stock concentration. Targets above your stock will show N/A.
| Target ppm | Stock / 1 L | Water / 1 L | Dilution Ratio | Common Use |
|---|---|---|---|---|
| 50 ppm | 100 mL | 900 mL | 1:9 | Light cleaning |
| 100 ppm | 200 mL | 800 mL | 1:4 | Surface disinfection |
| 200 ppm | 400 mL | 600 mL | 1:2 | Food-contact sanitizing |
| 500 ppm | 1000 mL | 0 mL | 1:0 | Heavy disinfection |
Pro Tips
Measure carefully
HOCl is more sensitive than many cleaners. Use a clean measuring container and avoid metal contamination if you want the batch to hold strength longer.
Storage
Use dark containers
Store the finished mix in an opaque bottle away from heat and sunlight. Clear bottles shorten shelf life and reduce effective ppm faster.
Labeling
Write the ppm on the bottle
Label the finished batch with the stock concentration, target ppm, and mix date so you can use it consistently and safely later.
Common Questions
Hypochlorous Acid Calculator FAQ
Quick answers on stock conversion, ppm targets, storage, and safe handling of HOCl mixes.
What target ppm should I use for routine cleaning?
100 ppm is a common starting point for surface disinfection, while 50 ppm is a lighter cleaning range and 200 ppm is often used for sanitizing where the label allows it.
Why does the target need to be lower than the stock?
Dilution can only reduce concentration. If the target exceeds the stock, you need a stronger source rather than more water.
Does HOCl lose strength over time?
Yes. Light, heat, and contamination all shorten shelf life. Make fresh batches and store them in opaque containers.
Can I use HOCl for food-contact or healthcare tasks?
Only if the product label specifically allows it and you verify the concentration with test strips. Those uses are sensitive to ppm errors.
What happens if my stock is lower than the target?
The mix is not physically possible with water alone. The calculator will warn you and you’ll need a stronger stock solution.
Data Integrity
Formula and source verification
This calculator uses the standard dilution identity C₁V₁ = C₂V₂. Stock strength entered as percent is converted using 1% = 10,000 ppm before solving V₁ = (C₂ / C₁) x V₂, and water is computed as V₂ - V₁.
Verified
Reference basis: Concentration math is anchored to standard analytical chemistry dilution equations, while safety and real-world use context is cross-checked against CDC and EPA disinfection guidance. ppm verification for critical use is emphasized because HOCl can lose strength with time, light, and handling.
LibreTexts — Concentration and Dilution
Academic chemistry source confirming the C₁V₁ = C₂V₂ dilution identity used to compute stock and water volumes.
LibreTexts ChemistryCDC — Cleaning and Disinfecting
Used to validate surface-cleaning and disinfection context, including contact-time and handling guidance for routine household use.
CDC Cleaning and DisinfectingEPA — List N Disinfectants
Used to align concentration guidance with label-first disinfectant use and product-specific efficacy requirements.
EPA List NPubChem — Hypochlorous Acid
Used as a chemical reference for HOCl identity and properties when documenting concentration and handling assumptions.
PubChem HOCl Profile