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Dilution Calculator
Work out exactly how much stock solution and diluent you need — for solution dilutions, serial dilutions, ratios, and dilution factors.
Short answer
Use C1V1 = C2V2: the stock volume is V1 = (C2 × V2) ÷ C1, then add diluent up to V2. To make 100 mL of 1 M from a 10 M stock, use 10 mL of stock and 90 mL of solvent. Enter your own numbers below — any consistent units work.
Stock to use (V1)
10 mL
Diluent to add
90 mL
Dilution factor
10×
Add 10 mL of 10 M stock to 90 mL of diluent for 100 mL of 1 M solution.
More dilution tools
Stock volume for common dilutions (100 mL final)
| Dilution factor | Stock to use | Diluent to add |
|---|---|---|
| 2× | 50 mL | 50 mL |
| 5× | 20 mL | 80 mL |
| 10× | 10 mL | 90 mL |
| 20× | 5 mL | 95 mL |
| 50× | 2 mL | 98 mL |
| 100× | 1 mL | 99 mL |
| 1000× | 0.1 mL | 99.9 mL |
For a 100 mL final volume. The math is unit-agnostic — the same stock volumes apply to µL or L, and to any concentration unit, as long as you keep units consistent.
How we calculate this
Every number on this page comes from the standard dilution relationships:
- Solution dilution. C1V1 = C2V2 — the solute amount is conserved, so the stock volume is V1 = (C2 × V2) ÷ C1 and the diluent is V2 − V1.
- Dilution factor. how many-fold the stock is diluted: C1 ÷ C2 (by concentration) or final volume ÷ sample volume (by volume).
- Serial dilution. the same factor is applied step after step, so concentration falls geometrically — stock ÷ factor^n at step n.
- Dilution ratio. a 1:N ratio is 1 part concentrate to N parts diluent, N + 1 parts total, an (N + 1)-fold dilution.
Assumptions
- Volumes are additive and mixing is ideal — fine for routine lab and cleaning dilutions, though concentrated acids/bases can show small volume-contraction effects.
- Concentrations and volumes are each entered in consistent units; the tool does not convert between unit systems.
- Educational estimates — for regulated or analytical work, follow your validated protocol.
Sources
Last reviewed: July 17, 2026
Frequently asked questions
Related tools
How do you calculate a dilution?+
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.
What is the dilution formula (C1V1 = C2V2)?+
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.
How do you make a 1:10 dilution?+
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.)
How do you do a serial dilution?+
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.
What is a dilution factor?+
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.
What units does this dilution calculator use?+
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.
Educational estimates only. Assumes ideal, additive mixing and consistent units; for regulated or analytical work, follow your validated protocol. Handle chemicals per their safety data sheet.