Dilution Calculator

It solves C1 x V1 = C2 x V2. C1 and V1 are the stock concentration and volume, C2 and V2 are the final concentration and volume. Because the moles of solute do not change when you add solvent, that product stays equal on both sides.

Solve for V1. The calculator rearranges to V1 = C2 x V2 / C1. Measure out that volume of concentrated stock, then add solvent until you reach the final volume V2. For example, 1 x from a 10 x stock in 100 units of final volume needs 10 units of stock.

Any consistent units. Use the same concentration unit for C1 and C2 (molar, mg/mL, percent, or fold such as 10x) and the same volume unit for V1 and V2 (litres, mL or microlitres). The answer comes back in whatever units you entered, since the equation is unit-agnostic.

The dilution factor is C1 / C2, which also equals V2 / V1. A factor of 10 means the stock is ten times stronger than the final solution, so one part stock is topped up to ten parts total. This calculator gives you the exact volumes behind any factor you need.

Yes. Choose C1 in the 'Solve for' menu and enter V1, C2 and V2. The tool computes C1 = C2 x V2 / V1, which is handy when you know how a diluted sample was prepared and want the original concentration.

Yes, one step at a time. Work out each tube in turn and use the previous step's final concentration as the next step's stock concentration C1. Repeating the single-step calculation down a series gives you every intermediate concentration and volume.

One equation can pin down only one unknown. If you leave two boxes blank or fill in all four, the calculator shows a short message asking for exactly three of C1, V1, C2 and V2 so the answer is unique.

Solving for a value can require dividing by another. If you ask for C1 while V1 is zero, or for C2 while V2 is zero, the result is undefined, so the tool refuses it and explains which value cannot be zero.

Everything is computed in your browser, so nothing is uploaded or stored. Results are rounded to nine decimal places, which removes floating-point noise while keeping small pipetting volumes accurate.