Calculate a final batch that includes every stock addition. The basal-medium amount is the volume left after serum and supplements have been subtracted.
Worked examples use illustrative inputs, independent of your current calculation and selected cell line. Replace them with measured values and your lab protocol.
How to use this tool
Choose the working cell line, then enter the final batch volume. The 100, 250 and 500 mL buttons and the 1–1,000 mL slider change the same input; the numeric field also accepts volumes outside the slider range.
Check the serum percentage against your formulation. Enable Pen–Strep only if your protocol calls for it, and check the concentration of the stock you actually have.
Enable up to three additional supplements. Each “Stock fraction” is the stock volume as a percentage of the final batch, not a mass concentration or a percentage of the basal medium.
For MCF7, supply the lab-confirmed insulin target in mg/mL. Read the dispensing recipe and check that basal medium plus all additions equals the requested final volume.
Formulas and units
1 mL = 1,000 µL; 1 L = 1,000 mL. Convert volumes to mL when combining them with cells/mL or mg/mL.
Percentage addition
V(addition) = V(final) × p / 100
p is the entered % v/v; use the same volume unit on both sides.
Stock dilution
C(stock) × V(stock) = C(final) × V(final)
So V(stock) = C(final) × V(final) / C(stock). Both concentrations must describe the same substance in matching units.
Enter a dilution as a percentage
Stock fraction (%) = 100 × C(final) / C(stock)
For example, a 100× stock used at 1× final contributes 1% of the final volume. Use this conversion for additional supplements.
Basal-medium balance
V(base) = V(final) − sum of all added stock volumes
Every serum, antibiotic and supplement volume is counted once. This calculator requires a positive basal-medium volume.
Worked examples
500 mL with serum and three additional stocks
Inputs. Final volume 500 mL; FBS 10%; Pen–Strep stock 1%; additional stock A 1%, B 2% and C 0.5%.
FBS: 500 × 10/100 = 50 mL.
Pen–Strep: 5 mL. Stocks A, B and C: 5 mL, 10 mL and 2.5 mL.
All additions: 50 + 5 + 5 + 10 + 2.5 = 72.5 mL.
Basal medium: 500 − 72.5 = 427.5 mL.
Result. 427.5 mL basal medium + 72.5 mL additions = 500 mL final.
Use a template without a separate required supplement to reproduce this example. These stock fractions illustrate volume accounting; they are not a recommended formulation.
Convert a concentration target into a stock fraction
Inputs. Hypothetical supplement: 2 mg/mL stock, 0.004 mg/mL target, 250 mL final batch.
Stock volume: 0.004 × 250 / 2 = 0.5 mL.
Stock fraction: 100 × 0.004 / 2 = 0.2%.
Enter 0.2 in an additional supplement’s Stock fraction field.
Result. 0.5 mL (500 µL) of this stock is included within the 250 mL final batch.
This is not an insulin recommendation. The remaining volume also needs to account for serum and any other additions.
Assumptions and interpretation
Volumes are treated as additive. The calculation does not assess chemical compatibility, stability, pH, osmolality or sterility.
The stock-dilution equation assumes the other components do not already contribute the substance being calculated. Check the basal formulation and avoid double-counting premixed supplements.
Concentration units matter: 1 mg/mL = 1,000 µg/mL. A volume fraction alone does not identify the final chemical concentration without the stock strength.
Adding serum to a full 500 mL bottle produces more than 500 mL. Here, 500 mL means the completed mixture.
References and source scope
These sources support the stated background and product references. Formulas explain this tool’s arithmetic; worked examples are not vendor recommendations or evidence of vendor endorsement.
General background on medium selection, counting, subculture, growth phases and cryopreservation. The worked examples here are original arithmetic demonstrations.
Selected cell-line product reference. Use its complete instructions and batch information for biological conditions; the examples below the calculator do not prescribe conditions for this line.