See the extra salt needed from a target salt percentage right away.
Clear single-column flow
%w/w / %w/v switch
Seawater and additives supported
Brine Concentration Calculator
Calculate how much salt you need from a target salt percentage. Switch between %w/w and %w/v, and reverse-calculate the percentage from the salt you actually used.
Includes initial salinity for seawater or existing brine, optional additives such as sugar, g/oz display, and approximate spoon-volume conversions.
Switch between %w/w (weight %) and %w/v (weight/volume %) and compare both views.
Account for starting salinity when you begin with seawater or existing brine.
Include additives such as sugar in the total weight for %w/w calculations.
Reverse-calculate the current percentage from the salt you actually added.
Reuse the setup with shareable URLs and last-state restore.
How to Use
- Choose %w/w or %w/v and check the short definition and example first.
- Enter the target salt percentage and the amount of liquid.
- If needed, open the advanced settings for initial salinity, additives, and display units.
- Read the salt-to-add result, then use the reverse card to confirm the percentage from your actual measured salt.
Examples
Make a 5% brine in %w/w
Input
5.0% w/w, 1000 g
Output
Salt to add: 52.6 g, predicted concentration: 5.00%
Make a 5% salt solution in %w/v
Input
5.0% w/v, 1000 mL
Output
Salt to add: 50.0 g, predicted concentration: 5.00%
Raise seawater from 3.5% to 5.0% w/w
Input
Target 5.0%, initial 3.5%, 1000 g
Output
Salt to add: 15.8 g
Reverse-calculate after using 50 g
Input
%w/w, 1000 g, actual salt 50 g
Output
Estimated salt %: 4.76%, difference from target: -0.24 pt
Quick Glossary
%w/w (weight %)
This shows what percentage of the total final weight is salt. A 5% w/w brine contains 5 g of salt in every 100 g of total mixture.
%w/v (weight/volume %)
This shows how many grams of salt are present per 100 mL of solution. A 5% w/v brine contains 5 g of salt in every 100 mL.
Initial salinity
The salt percentage that seawater or an existing brine already has before you add more salt.
Additives
Ingredients other than salt, such as sugar. In %w/w mode they become part of the total final weight.
Formulas
%w/w: ds = (t × (m0 + a) - s0) ÷ (1 - t)%w/v: ds = (t - p0) × V%w/w reverse: percent = (s0 + sUsed) ÷ (m0 + a + sUsed) × 100%w/v reverse: percent = (s0 + sUsed) ÷ V × 100
FAQ
What if I start with seawater or an existing brine?
Enter the current salinity in the advanced settings under “Initial salt %”. The result will show the extra salt to add. If the starting salinity is already above the target, you need dilution rather than more salt.
Can I see the result in oz instead of g?
Yes. Switch the display unit between g and oz in the advanced settings. The calculation itself is still normalized in grams internally.
Can I add sugar too?
Yes. Add sugar or other ingredients in the advanced settings. In %w/w they become part of the total final weight, so the same amount of salt gives a slightly lower percentage. In %w/v they are shown only as a note and do not change the main calculation.
When should I choose %w/w or %w/v?
Choose %w/w when you weigh everything and want repeatable batches. Choose %w/v when the process is controlled by volume. For a nominal 5% brine at 1 L, %w/w needs about 52.6 g while %w/v needs 50 g.
Are spoon conversions exact?
No. Spoon estimates vary a lot with grain size and salt type. Use them only as rough guidance and weigh in grams for accurate work.
Does this page also cover food safety or recipe guidance?
No. This page is only for concentration calculation. Keep sanitation, storage time, temperature control, safety, and full recipe decisions in separate documentation.
Important Notes
- This page is a calculation tool. Food safety, sanitation, storage time, temperature control, and recipe decisions should be managed elsewhere.
- Spoon-volume conversions are only estimates. Weighing in grams is strongly recommended when accuracy matters.
- %w/v here is treated as a practical volume-based estimate and does not model the exact volume change after dissolving salt.
- If the starting salinity is already above the target, this tool does not calculate how much to dilute.