Dilution Factor Calculator

Yes — it's a free, in-browser dilution factor calculator with no signup and no ads gating the result. Your inputs stay on your device.

Use the dilution equation C1V1 = C2V2, where C1 and V1 are the concentration and volume of the stock solution and C2 and V2 are the concentration and volume you want. Solve for the stock volume: V1 = (C2 × V2) ÷ C1, then add diluent up to V2. For example, to make 100 mL of 1 M from a 10 M stock, use 10 mL of stock and 90 mL of solvent.

C1V1 = C2V2 states that the amount of solute stays the same before and after dilution — concentration times volume (the amount) is conserved. It works in any consistent units: keep both concentrations in the same unit (M, mM, µM, mg/mL, or %) and both volumes in the same unit, and the equation gives the stock volume to use.

A 1:10 dilution means 1 part sample to 10 parts diluent — 11 parts total, an 11-fold dilution. To make 1,100 mL, combine 100 mL of concentrate with 1,000 mL of diluent. (Some fields read '1:10' as 1-in-10 total; this calculator uses the 1 part to 10 parts convention and shows the resulting dilution factor so it's unambiguous.)

A serial dilution repeats the same dilution step down a row of tubes, so the concentration drops by the same factor each time (for example 10-fold: stock, then 1/10, 1/100, 1/1000…). Transfer a fixed volume from each tube into the next, which already holds diluent. The serial dilution tool lists the concentration in every tube plus the transfer and diluent volumes.

The dilution factor is how many times more dilute the final solution is than the stock — either the ratio of concentrations (C1 ÷ C2) or of volumes (final volume ÷ sample volume). A dilution factor of 10 means the stock was diluted 10-fold. Multiply a measured concentration by the dilution factor to back-calculate the original.

Any — the math is unit-agnostic. As long as both concentrations share a unit (molarity, mg/mL, %, ppm) and both volumes share a unit (µL, mL, L), the result comes out in the same units you entered. Nothing you type leaves your browser; there's no signup.