Set a target strength and get the mass to weigh out
The confusing part of mixing a citric acid solution is whether the percentage counts the water alone or the finished liquid. Enter the water and the strength you are aiming for, and the page returns the citric acid to weigh out, the total mass of the solution and the actual strength recalculated from a mass rounded to a tenth of a gram. The ratio against the water on its own is shown as well, so the two readings never get mixed up.
How the numbers are worked out
Because the target is read against the whole solution, the acid mass is the water mass times the strength, divided by 100 minus that strength. Add 50 g to 1,000 g of water and the total is 1,050 g at roughly 4.76 percent. Water is treated as 1 g per milliliter, an assumption stated here rather than applied silently, and grams and milliliters are not swapped anywhere else. No officially recommended strength is offered: the ratios that circulate are tied to a surface or a product and are not a standard. Figures as of October 2026.
Water hardness unit conversion, contact times and which surfaces tolerate acid are not covered here. For working strength and precautions, follow the product label and the manufacturer's instructions.
Frequently Asked Questions
No officially recommended strength is offered here. Ratios circulate widely, but they are common practice tied to a particular surface or product rather than a published standard. If your product prints a working strength, enter that.
On the whole solution by mass. Adding 50 g of citric acid to 1,000 g of water gives 1,050 g in total and a strength of about 4.76 percent, not 5. To keep that clear, the ratio against the water alone is shown on its own line as well.
This calculation assumes 1 mL of water weighs 1 g, which is close enough at room temperature. Metric units are kept on both language versions because the arithmetic is mass-based, and the assumption does not carry over to other liquids.