Hydrogen Peroxide Dilution Calculator

Step 30%, 35% or 12% hydrogen peroxide down to the strength you need, calculated by weight, the way peroxide is sold.

30% → 3%30% → 8%12% → 3%35% → 3%1:9
Target as

      Reviewed by Andre Taki, Chief Commercial Officer, Alliance Chemical. Densities: Laliberté (2009) and the CRC Handbook; bleach strength from Alliance's TDS. Check the SDS for your lot before mixing.

      02

      Choose The Right Starting Peroxide

      H₂O₂ buying decisions depend on whether the working solution is close to what you buy, or whether you want one concentrate feeding multiple targets. Buying 30% to dilute down to 3% makes sense when you need flexibility. Buying 3% directly makes sense when that is the end-use strength.

      Buying Guide

      3% technical is the strength most customers already know — equivalent to household peroxide. Choose it when that is the end-use strength and you do not want to dilute on-site.

      12% technical is a mid-tier concentrate often used in hair, pool, and light industrial applications. It is a convenient midpoint when dilution from 30% feels aggressive but 3% is too weak.

      30% technical is the flexibility stock. One drum can feed 3%, 6%, 10%, and 12% working solutions depending on the day. Handling requirements are real — 30% peroxide is a strong oxidizer — but the per-unit cost advantage is significant.

      Above 30%, handling risk rises sharply. For most industrial and light-lab work, 30% is the practical ceiling. Anything stronger should be matched to a documented process with trained handlers.

      Hydrogen Peroxide 3% Technical Grade

      Hydrogen Peroxide 3% Technical Grade

      Ready-to-use household-equivalent strength. Buy this when 3% is the end-use and you do not want to dilute.

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      Hydrogen Peroxide 12% Technical Grade

      Hydrogen Peroxide 12% Technical Grade

      Mid-tier concentrate for pool, hair, and light industrial use. Comfortable step-down point toward 3% working solutions.

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      Hydrogen Peroxide 30% Technical

      Hydrogen Peroxide 30% Technical

      Maximum-flexibility concentrate. Feeds multiple working strengths from a single stock, with real oxidizer handling requirements.

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      30 percent hydrogen peroxide product image from Alliance Chemical
      30% technical peroxide is the flexible stock when one facility needs to make 3%, 8%, and 10% working solutions from the same drum.
      03

      Common H₂O₂ Dilution Targets

      H₂O₂ working strengths are driven by the job. Household-equivalent 3% is the most common step; stronger targets show up in heavy-duty cleaning, agriculture, and specialty workflows.

      Common recipes
      Starting Stock Target Typical Use Notes Calculator
      30% technical 3% Household-equivalent strength Classic dilution target for DIY, pet care, and plant applications that assume pharmacy-grade 3% peroxide. Open
      30% technical 8% Heavy-duty cleaning Heavier-duty surface cleaning where 3% is too weak. Verify contact time and material compatibility before scaling. Open
      12% technical 3% Step-down from mid-tier stock Simpler dilution step when 12% is already on-site and a 3% working solution is needed. Open
      30% technical 1:9 water Ratio-written SOP One part 30% to nine parts water lands near 3%. Use this entry when your procedure is written as parts, not final percent. Open
      04

      H₂O₂ Handling Reality Check

      Hydrogen peroxide gets a pass in most people's heads because the household version is stored under the sink. Above 10%, that mental model breaks — concentrated peroxide is a strong oxidizer with real fire and burn risk.

      Guardrails

      Concentrated peroxide is an oxidizer, not a benign cleaner. 30% H₂O₂ on skin causes chemical burns. On combustible material (rags, paper, organic solvents) it can start a fire. Store away from fuels, reducing agents, and transition metals.

      Use compatible materials. HDPE and fluoropolymer containers are peroxide-safe. Uncoated metals — especially iron, copper, and brass — catalyze decomposition, release O₂ and heat, and pressurize closed containers. Never store concentrated peroxide in a metal vessel.

      Heat decomposition matters. H₂O₂ slowly decomposes to water and oxygen at room temperature. Elevated temperature, contamination, or catalyst exposure accelerates this exponentially. Keep containers vented where applicable, store cool, and rotate stock.

      Dilute into water, not the other way around. Add peroxide to water slowly to control the heat of mixing. Never mix concentrated peroxide with acetone, organic solvents, or unknown chemistries — some combinations produce explosive peroxides.

      Questions

      How do I dilute 30% hydrogen peroxide to 3%?
      Use one part 30% H₂O₂ to nine parts water (distilled if the end use is sensitive). That lands at 3% final concentration. The calculator on this page returns exact volumes for any batch size.
      Can I substitute 12% peroxide for 3% household peroxide?
      Only after diluting. 12% is four times stronger than household 3%, which changes dwell time, material compatibility, and burn risk. For recipes calling for 3%, dilute to 3% first rather than substituting.
      What concentration of H₂O₂ is strongest you sell?
      Alliance Chemical stocks peroxide up to 30% in technical and ACS grades. Above 30%, handling complexity rises sharply and is typically restricted to trained, documented industrial processes.
      Does peroxide lose strength over time?
      Yes. Peroxide decomposes to water and oxygen even in ideal storage. Rate depends on temperature, container material, and contamination. Keep it cool, in HDPE or fluoropolymer, away from metals, and rotate stock.