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Help & supplies
Use the numbers from your label and instructions. We check the math. We do not tell you what to take or what to mix.
Looking for BAC water?
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Check the product instructions first. A link is not advice to use it.
What to have ready
Start with the instructions for your exact product.
- The right liquid. Use the liquid named in those instructions. Not every product uses BAC water.
- A way to measure it. Check the scale and the marks on your device.
- A record of your numbers. Keep the label and your result together.
We may earn a commission. We don’t add a markup; you buy directly from our partner. For laboratory research only. Not for human consumption or veterinary use.
The supplier’s water is for lab research only. We do not decide which product you need.
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Copy the amounts and final volume from your own instructions.
Choose the exact product before entering numbers. IU products, blends, solutions and lab water open their own calculators.
How the volume changes concentration
Concentration in mg/mL equals the total amount in mg divided by the final liquid volume in mL. The volume for an entered measurement equals that measurement in mg divided by the concentration.
For a mathematical example, 10 mg in a final 2 mL is 5 mg/mL. An entered 0.4 mg measurement corresponds to 0.08 mL, or 8 U-100 units. In a final 4 mL instead, the concentration would be 2.5 mg/mL and that same amount would correspond to 0.16 mL.
These examples demonstrate arithmetic, not product preparation. Changing liquid volume may be incompatible with the product instructions or vial capacity. Read what a calculator cannot verify.
Does BAC water establish a shelf life?
This calculator cannot establish sterility or stability. Do not treat a preservative, a clear-looking solution or a correct calculation as proof that a mixture remains usable. Follow the exact product's storage and discard instructions.
The BAC water storage reference separates unopened expiry, opened-vial guidance and reconstituted-product instructions. They are different questions.
Common questions
- How do I know how much BAC water to add?
- The instructions for the exact product, or the stated concentration of an existing solution, set the final volume. Vial strength alone cannot answer it: 10 mg in 1 mL is 10 mg/mL and the same 10 mg in 2 mL is 5 mg/mL. Enter the volume from your instructions and this calculator shows the resulting concentration so you can check the arithmetic.
- How much BAC water goes in a 5 mg or 10 mg vial?
- There is no universal volume. As arithmetic only, 5 mg in 1 mL is 5 mg/mL, 5 mg in 2 mL is 2.5 mg/mL, and 10 mg in 2 mL is 5 mg/mL. Which volume applies to a real product comes from its instructions, vial capacity and compatibility, none of which a calculator can verify.
- Does adding more BAC water change the amount in the vial?
- No. More liquid lowers the concentration, but the total mass stays the same before any losses. 6 mg in 2 mL is 3 mg/mL; the same 6 mg in 3 mL is 2 mg/mL. Each measured portion then needs a larger volume for the same mass.
- Is the final volume the same as the water added?
- Not necessarily. The calculator uses the final solution volume. Dissolved material, losses and vial capacity are not inferred, so use the final volume stated in your instructions or measured for an existing solution.
More on dilution arithmetic · Does a peptide need BAC water?