Dilution Ratio Calculator
Use this dilution ratio calculator to turn a 1 : N ratio into the exact amount of stock and solvent to combine. Here 1 : N means 1 part stock to N parts solvent (so the total is 1 + N parts). Enter N and the final volume to get both volumes and the dilution factor.
Enter the ratio N and a total volume to see how much stock and solvent to combine.
How dilution ratios work
A dilution ratio describes how much concentrated stock to mix with how much solvent (water, buffer, or another diluent). The number of parts tells you the proportions; multiply by a total volume to get real amounts to measure out.
The 1:N convention used here
This tool reads 1 : N as 1 part stock to N parts solvent. That means the finished solution is made of 1 + N total parts, and the concentration is reduced by a factor of 1 + N (often written as "X-fold"). For a 1:9 ratio you get 10 total parts — a 10× dilution.
Be careful: some people and protocols read 1 : N as "1 part in N total" instead — i.e. 1 part stock makes up N parts of the finished solution, which is an N-fold dilution using 1 part stock plus N − 1 parts solvent. The two conventions disagree (a 1:10 ratio is 11×, while "1 in 10" is 10×), so always confirm which one your method intends. If you actually want a target concentration rather than a ratio, the dilution calculator solves C₁V₁ = C₂V₂ directly.
Worked example
Suppose you want a 1:10 dilution and need 500 mL total. With N = 10 the total is 1 + 10 = 11 parts, so the stock is 500 ÷ 11 ≈ 45.5 mL and the solvent is 500 − 45.5 ≈ 454.5 mL. The dilution factor is 1 + 10 = 11×: the final concentration is one eleventh of the stock.
When to use a series instead
A single ratio works for one dilution step. If you need many ordered dilutions — for example a tenfold series across several tubes — the serial dilution calculator computes the concentration and transfer volume for every step.
Frequently asked questions
›What does a 1:10 dilution mean?
On this calculator, 1:10 means 1 part stock combined with 10 parts solvent, giving 11 parts total. So a 1:10 dilution of 500 mL is about 45.5 mL of stock topped up with 454.5 mL of solvent, and the concentration drops by a factor of 11 (an 11× dilution).
›What is the difference between "1 part in N" and a "1:N ratio"?
They are two different conventions. A 1:N ratio (used here) means 1 part stock to N parts solvent, so the total is 1 + N parts and the dilution factor is 1 + N. "1 part in N total" means 1 part stock makes up N parts of finished solution, so the dilution factor is exactly N. For example, 1:9 as a ratio is a 10× dilution, while "1 in 10" is also a 10× dilution but uses 1 part stock plus 9 parts solvent — always confirm which convention a protocol means.
›How do I calculate a dilution ratio?
Take your total volume and divide it by (1 + N), where N is the parts of solvent per 1 part stock. That gives the stock volume; the solvent volume is the total minus the stock. For a 1:N ratio the dilution factor is 1 + N. This calculator does the arithmetic for you — just enter N and the final volume.
›Is this dilution ratio calculator free?
Yes. This dilution ratio calculator is completely free, runs entirely in your browser, needs no sign-up, and never sends your numbers to a server.
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