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Dilution Calculator

Applies the dilution equation C1·V1 = C2·V2 to find the missing one of stock concentration, stock volume, final concentration or final volume, plus the solvent to add and the dilution factor.

When to use

You are diluting a stock solution and need how much stock to take, the final volume to make up, or the concentration that results.

Do not use when: You are preparing a solution from solid solute (use molarity) or the concentrations are in mass percent with very different densities (C1V1 = C2V2 assumes volumes are additive and the unit is amount per volume).

Formula

C1 × V1 = C2 × V2; solvent_volume_to_add = V2 − V1; dilution_factor = C1 / C2

Exactly three of the four quantities must be given. The relation assumes the amount of solute is conserved and volumes are additive, which holds well for dilute aqueous solutions.

Inputs

Parameter	Type	Required	Description
`stock_concentration`	number	no	Concentration of the stock solution in any unit (M, mM, mg/mL, %, X); all concentrations share the unit. Range: > 0
`stock_volume`	number	no	Volume of stock solution taken, in any unit shared with final_volume (mL, L, µL). Range: > 0
`final_concentration`	number	no	Concentration after dilution, same unit as stock_concentration. Range: > 0
`final_volume`	number	no	Total volume after dilution, same unit as stock_volume. Leave empty to solve for it. Range: > 0

Outputs

Output	Type	Description
`stock_concentration`	number	C1, given or solved.
`stock_volume`	number	V1, given or solved.
`final_concentration`	number	C2, given or solved.
`final_volume`	number	V2, given or solved.
`solvent_volume_to_add`	number	V2 − V1: diluent (water, buffer) to add to the stock volume.
`dilution_factor`	number	C1 / C2 = V2 / V1, e.g. 4 means a 1:4 (4×) dilution.
`solved_for`	string	Name of the quantity that was left empty and computed.

Example

2 M stock, 25 mL, to 0.5 M: {"stock_concentration":2,"stock_volume":25,"final_concentration":0.5} → {"final_volume":100,"solvent_volume_to_add":75,"dilution_factor":4,"solved_for":"final_volume"}

10 mL of 0.1 M made up to 250 mL: {"stock_concentration":0.1,"stock_volume":10,"final_volume":250} → {"final_concentration":0.004,"solvent_volume_to_add":240,"dilution_factor":25,"solved_for":"final_concentration"}

GET https://tttkmbb.com/api/v1/calculate/dilution?stock_concentration=2&stock_volume=25&final_concentration=0.5

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/dilution (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/dilution · Markdown: https://tttkmbb.com/chemistry/dilution.md · JSON definition: https://tttkmbb.com/chemistry/dilution.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="dilution"
OpenAPI operationId: calculate_dilution
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

OpenStax Chemistry 2e – 3.3 Molarity – Dilution of Solutions (textbook)
Wikipedia – Dilution (reference)

FAQ

Which units can I use?

Any, as long as both concentrations share one unit and both volumes share one unit; the result comes out in the same units (e.g. mM and µL).

What is the difference between a 1:4 dilution and a 1-in-4 dilution?

Both conventions exist; here dilution_factor = 4 means 1 part stock brought to 4 parts total (3 parts solvent added), which is the C1V1 = C2V2 interpretation.

Related calculators

Molarity Calculator — Prepare the stock solution from solid solute first.
Mass Percent Calculator — Mass-based concentration units (%, ppm, ppb).