This dilution calculator uses the standard relationship C1V1 equals C2V2 to tell you exactly how much concentrated stock solution and how much diluent you need to reach a target concentration and final volume. Diluting a stock is one of the most common tasks in a chemistry, biology or microbiology lab, as well as in brewing, aquariums, hydroponics, cleaning and pool care, and getting it right matters because too strong or too weak a solution can ruin an experiment or a batch. The principle is simple: when you dilute, you add solvent but the amount of solute stays the same, so the concentration times the volume is constant before and after. You enter the concentration of your stock, the concentration you want to end up with, and the final volume you need, and the calculator returns the volume of stock to measure out and the volume of diluent, usually water, to add to it. The only rule is consistency: use the same concentration unit for both concentrations, whether molar, percent or grams per litre, and the same volume unit throughout. The maths cannot make a weaker stock into a stronger solution, so the target concentration must be lower than the stock. Enter your three known values to see the volumes you need straight away.
Use the same concentration unit for both, and the same volume unit throughout. The target must be weaker than the stock. Estimate only.
Rearranging C1V1 equals C2V2, the stock volume V1 is the desired concentration times the final volume, divided by the stock concentration. The diluent to add is the final volume minus that stock volume. The dilution factor is the stock concentration divided by the desired concentration.
To make 500 mL of a 2 molar solution from a 10 molar stock, you need 2 times 500 over 10, which is 100 mL of stock, topped up with 400 mL of diluent. That is a five times dilution.
If you've found a bug, or would like to contact us, or learn more about James Graham and Calculate.co.nz.
Calculate.co.nz is partnered with Interest.co.nz for New Zealand's highest quality calculators and financial analysis.
All calculators and tools are provided for educational and indicative purposes only and do not constitute financial advice.
Calculate.co.nz is proudly part of the Realtor.co.nz group, New Zealand's leading property transaction literacy platform, helping Kiwis understand the home buying and selling process from start to finish. Whether you're a first home buyer navigating your first property purchase, an investor evaluating your next acquisition, or a homeowner planning to sell, Realtor.co.nz provides clear, independent, and trustworthy guidance on every step of the New Zealand property transaction journey.
Calculate.co.nz is also partnered with Health Based Building and Premium Homes to promote informed choices that lead to better long-term outcomes for Kiwi households.
Calculate.co.nz is hosted in Auckland via SiteHost new Zealand.
All content on this website, including calculators, tools, source code, and design, is protected under the Copyright Act 1994 (New Zealand). No part of this site may be reproduced, copied, distributed, stored, or used in any form without prior written permission from the owner.
About & trust: Why Calculate is NZ's most comprehensive · By the Numbers · How we compare · Editorial standards · How we keep data current · NZ finance glossary · Research & data · Financial literacy NZ · About · Privacy policy · Terms of use
Reviewed and maintained. Last reviewed 2026-06-07 and checked on a twice-monthly cycle against IRD, RBNZ and Stats NZ. How we keep data current.
© 2026 Calculate.co.nz. All rights reserved. Building free NZ calculators since 2011.