Dilution Calculator
Dilution calculator (M₁V₁ = M₂V₂) — enter three of initial concentration, initial volume, final concentration and final volume, solve for the fourth. Curriculum-aligned.
Dilution Calculator
Enter three values and leave the fourth blank — the calculator solves for it. Concentration is in mol/L; volume in L or mL.
- Curriculum
- English (global) — Cambridge International + IB
- Built against
- Cambridge IGCSE Chemistry 0620 + IB Diploma (2023–2025) — Solution Dilution
- Unit system
- SI primary; US/imperial readout below
- First published
- 2 Jun 2026
- Last updated
- 4 Sep 2026
View authoritative scientific sources
- IUPAC — solution nomenclature
- BIPM SI Brochure, 9th edition (2019)
- Atkins / Campbell Chemistry — dilution
- Dilution — Encyclopædia Britannica
⚠️ Educational use only — see full disclaimer
EDUCATIONAL USE DISCLAIMER
This calculator is provided for educational and reference purposes only. It is not a substitute for instruction from a qualified teacher, your prescribed textbook, or your school's official curriculum materials.
When preparing for examinations, always cross-check our calculations and notation against your current syllabus and your teacher's guidance. Syllabus conventions and accepted notation vary between curricula and may change between examination years.
If you believe any calculation, notation, or curriculum reference in this tool is inaccurate, please let us know via the feedback button. We review feedback promptly and update tools when verified corrections are needed.
RECATOOLS accepts no liability for academic, examination, professional, or research outcomes arising from use of this tool.
How to Use the Dilution Calculator
Pick your curriculum
Use the curriculum pills above to match your syllabus (Cambridge/IB, 高考 or SBMPTN). Terminology and the whole page follow your selection.
Enter three values
Type three of initial concentration, initial volume, final concentration and final volume — leave the one you want to find blank.
Read the result
The calculator solves for the blank value, usually the volume of stock solution needed or the final concentration.
Check against your syllabus
The Tool Information block shows exactly which syllabus this is built against. Spot something off? Use the feedback button.
Dilution, in Your Curriculum's Words
Dilution (M₁V₁ = M₂V₂)
Example: What volume of a 2.0 mol/L stock solution is needed to make 4.0 L of a 0.50 mol/L solution?
Given: M₁ = 2.0 mol/L, M₂ = 0.50 mol/L, V₂ = 4.0 L. Using M₁V₁ = M₂V₂:
V₁ = M₂V₂ / M₁ = (0.50 × 4.0) / 2.0 = 1.0 L
The dilution equation M₁V₁ = M₂V₂ says that the amount of solute does not change when a solution is diluted by adding solvent. M₁ and V₁ are the initial concentration and volume (the concentrated stock), while M₂ and V₂ are the final concentration and volume after dilution. Because the number of moles stays the same, the product of concentration and volume is equal on both sides.
The most common use is finding the volume of stock solution to take in order to make a dilute solution of a given concentration. Molar concentration has no imperial equivalent, so results are shown in mol/L; volumes can be entered in litres or millilitres and are shown in litres. All calculation happens in your browser — nothing is uploaded, and the tool works offline once loaded.
When you dilute a solution you add solvent, not solute — the number of moles stays the same, only the concentration falls.
10 Facts About Dilution
The dilution equation: M₁V₁ = M₂V₂.
On dilution the moles of solute stay the same.
Adding solvent lowers the concentration.
The dilution factor = V₂ / V₁.
M is usually in mol/L (molar).
It works for any concentration unit (mol/L, g/L, %).
Always add acid to water, never the reverse.
Concentrated stock solutions save storage space.
Serial dilution reaches very low concentrations.
This calculator runs in your browser — your working stays private.
Frequently Asked Questions
- M₁V₁ = M₂V₂ — the product of concentration and volume before dilution equals that after dilution. The calculator solves for whichever value you leave blank, whether an initial/final concentration or an initial/final volume, as long as the other three are known.
- Because dilution only adds solvent, not solute, the number of moles of solute does not change. The number of moles equals concentration times volume (n = M × V), so M₁V₁ (moles before) must equal M₂V₂ (moles after).
- Concentration is in moles per litre (mol/L or M), and volume in litres or millilitres. Molar concentration has no imperial equivalent, so results are shown in mol/L; volumes are converted to litres first. You may mix volume units — the calculator reconciles them.
- Enter the stock concentration (M₁), the final concentration you want (M₂) and the final volume (V₂), and leave V₁ blank. The calculator finds the volume of stock to take; you then add solvent up to the final volume.
- Mathematically the formula holds for any concentration unit (g/L, %, etc.) as long as M₁ and M₂ use the same unit. This calculator labels the result mol/L, but the numbers are still correct if you stay consistent with your own units.
- The chemistry — M₁V₁ = M₂V₂ — is identical worldwide. What changes is the terminology; "dilution" is 稀释 in Chinese. The calculated value is the same.
- The Tool Information block lists the exact syllabus for your selected curriculum (e.g. SBMPTN/SNBT Kimia). It is a study aid, not a substitute for your official syllabus or teacher.
- No. Every calculation runs in your browser; nothing you type is uploaded. It works offline once the page has loaded.
- Completely free, no account or usage limit. It runs entirely in your browser and collects no data.
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Method & sources
How it computes
C1 V1 = C2 V2, which holds because the amount of solute does not change on dilution. The assumption hiding inside it is that volumes are ADDITIVE, and they are not exactly: mixing ethanol and water contracts, so 50 mL plus 50 mL gives roughly 96 mL, not 100.
What this tool implements
- Volume additivity is assumed and stated. For aqueous salt and most bench dilutions the error is negligible; for alcohol-water it is percent-level and visible.
- Concentrations must be in the same units on both sides. The equation is dimensionally forgiving, which is exactly why unit mismatches survive it silently.
- Serial dilution multiplies the factors rather than adding them, and a stated fold-change should say which it is.
Sources
- IUPAC Compendium of Chemical Terminology (Gold Book), 'amount concentration' and 'dilution': https://goldbook.iupac.org/
- IUPAC, Quantities, Units and Symbols in Physical Chemistry (the Green Book), 3rd edition 2007.
What can make this go out of date
- None.
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