Scale a solution recipe
A recipe written for one volume, at the volume you actually want to make.
Free, no account needed. Nothing you type is sent anywhere or stored — the arithmetic runs in your browser.
Inputs
Components
| Component | In the recipe | Scaled amount | |
|---|---|---|---|
| 25 | |||
| 6.25 | |||
| Total | 31.25 | ||
Results
Scale factor
2.5
The arithmetic
Every component is multiplied by target volume ÷ original volume. Type the recipe once, change the volume, and the whole column moves together — which is the part that goes wrong when it is done by hand and one line gets missed.
Two things that do not scale
The pH adjustment. Acid or base added to bring a buffer to pH is not a component of the recipe — it is however much it takes on the day, at the volume you are making. Scaling the volume of HCl somebody wrote down last time will overshoot or undershoot, and the answer is to titrate again.
The final make-up. “Make up to 1 L” becomes “make up to 250 mL”, not “add 250 mL”. The solids and the concentrated stocks take up room, and at a large scale-down that difference is a real fraction of the volume.
Scaling up is not always safe
A recipe that dissolves easily at 100 mL may not at 2 L without heat or a stirrer, and something near its solubility limit will come out of solution on the way. If you are scaling by more than a few fold, make it once and watch it rather than trusting the column.