Dilution Calculator
Percent
Dilute percentage solutions — % w/v, v/v, and w/w. Calculate volumes for bleach, hydrogen peroxide, disinfectants, and chemical stock solutions.
What Is a Dilution Calculator Percent?
A dilution calculator percent applies C₁V₁ = C₂V₂ to percentage-based concentrations — % w/v (grams per 100 mL), % v/v (mL per 100 mL), and % w/w (grams per 100 grams). Percentage concentration is the standard for household chemicals, disinfectants, and many pharmaceutical preparations. Enter the stock percentage, desired percentage, and final volume to get the exact volumes of concentrate and diluent.
Benefits
- Works with % w/v, v/v, and w/w formats
- Calculates bleach and peroxide dilutions instantly
- Shows concentrate and water volumes for any target
- Common chemical dilution presets
Applications
- Bleach dilution for disinfection (sodium hypochlorite)
- Hydrogen peroxide dilution for wound care or cleaning
- Acid and base dilution for chemistry labs
- Formaldehyde and glutaraldehyde dilution for histology
Percent solutions dominate everyday chemistry. Household bleach is ~5.25% sodium hypochlorite. Hydrogen peroxide comes in 3%, 30%, and 35% grades. Rubbing alcohol is 70% isopropanol. Acetic acid (vinegar) is ~5% v/v. This percent dilution calculator helps you dilute any of these to a target percentage — whether you prepare 0.5% bleach for surface disinfection or 10% formalin for tissue fixation.
Percent Dilution Equation
The percent dilution equation uses C₁V₁ = C₂V₂ where concentrations are in percentage. C₁ is the stock percentage, V₁ is the volume of concentrate, C₂ is the target percentage, and V₂ is the total final volume. The equation works identically for w/v, v/v, and w/w — as long as both C₁ and C₂ use the same percent type.
Rearrange the equation to solve for any unknown:
V₁ = (C₂ × V₂) ÷ C₁— how much stock to pipetteC₂ = (C₁ × V₁) ÷ V₂— what concentration you'll getV₂ = (C₁ × V₁) ÷ C₂— total volume neededFor w/v percent (most common in biology and pharmacy), 1% = 1 g per 100 mL = 10 mg/mL. For v/v percent (used for liquids like ethanol), 1% = 1 mL per 100 mL. For w/w percent (used for solid mixtures and concentrated acids), 1% = 1 g per 100 g. Concentrated sulfuric acid is sold as 96–98% w/w by suppliers like Fisher Scientific and Sigma-Aldrich.
Percent Dilution Factor
The dilution factor for percent solutions equals C₁% ÷ C₂%. Diluting 30% hydrogen peroxide to 3% gives a factor of 10. Diluting 5.25% bleach to 0.5% gives a factor of 10.5. The factor tells you how much concentrate goes into the final volume.
The CDC recommends 0.5% (5,000 ppm) sodium hypochlorite for general surface disinfection and 0.1% (1,000 ppm) for routine environmental cleaning. Starting from 5.25% household bleach: 0.5% requires about a 10.5× dilution (1 part bleach in 10.5 total), and 0.1% requires about a 52.5× dilution. This percent dilution calculator gives you the exact volumes for any container size.
Step-by-Step Dilution Calculator Percent Guide
Follow these steps to calculate your dilution:
Serial Percent Dilutions
Serial percent dilutions create a range of concentrations for testing efficacy. For example, testing bleach effectiveness against different organisms may require concentrations from 5% down to 0.01% in two-fold steps.
Environmental health officers and infection control practitioners at hospitals prepare log-dilution series of disinfectants to verify minimum effective concentration (MEC). The AOAC Use Dilution Test and EN 14476 viricidal activity test both require defined dilution series. Manufacturers of disinfectants like Clorox Healthcare, Ecolab, and GOJO (Purell) submit serial dilution efficacy data for EPA or Health Canada registration.
Dilution Calculator Percent Example
Problem: A hospital infection control team needs 2 L of 0.5% sodium hypochlorite solution from standard 5.25% household bleach for surface disinfection per CDC guidelines.
V₁ = (C₂ × V₂) ÷ C₁V₁ = (0.5 × 2000) ÷ 5.25 = 190.5 mLWater = 2000 − 190.5 = 1809.5 mLDF = 5.25 ÷ 0.5 = 10.5× dilutionFrequently Asked Questions
Use V₁ = (target% × final volume) ÷ stock%. For 0.5% from 5.25% bleach in 1 gallon (3785 mL): V₁ = (0.5 × 3785) ÷ 5.25 = 360.5 mL of bleach + 3424.5 mL water. This gives approximately 5,000 ppm available chlorine, which is the CDC-recommended concentration for general surface disinfection. Prepare fresh solutions daily as sodium hypochlorite degrades.
w/v = grams per 100 mL. v/v = mL per 100 mL. w/w = grams per 100 grams. A 10% w/v NaCl solution contains 10 g NaCl in 100 mL total solution. A 70% v/v ethanol contains 70 mL ethanol in 100 mL total. A 37% w/w HCl contains 37 g HCl per 100 g solution. The type matters — 10% w/v is NOT the same as 10% w/w for most solutes. This percent dilution calculator works with all three types as long as C₁ and C₂ use the same notation.
Divide ppm by 10,000. 1% = 10,000 ppm. So 5,000 ppm = 0.5%, 1,000 ppm = 0.1%, and 100 ppm = 0.01%. For bleach: 5.25% = 52,500 ppm. The CDC's 5,000 ppm recommendation = 0.5%. For water treatment, typical chlorine residual is 0.2–2 ppm = 0.00002–0.0002%. This percent dilution calculator works with percentages — convert from ppm first if needed.