Calculator Inputs
Formula Used
The calculator uses the standard dilution relationship:
C1 × V1 = C2 × V2
V1 = C2 × V2 ÷ C1
Diluent volume = V2 − V1
Dilution factor = C1 ÷ C2 = V2 ÷ V1
Concentration units are converted within the same unit family before solving. Volume units are converted to liters internally.
How to Use This Calculator
- Select the unknown value in the solve field.
- Enter all other concentration and volume values.
- Choose matching concentration unit families.
- Add overage when extra solution is needed.
- Add a rounding step if pipette limits matter.
- Press calculate to see the result above the form.
- Use CSV or PDF download for lab records.
Example Data Table
| Stock C1 | Target C2 | Final Volume | Stock Volume | Diluent Volume | Dilution Factor |
|---|---|---|---|---|---|
| 100 mM | 10 mM | 50 mL | 5 mL | 45 mL | 10x |
| 100 mg/mL | 2 mg/mL | 25 mL | 0.5 mL | 24.5 mL | 50x |
| 5% | 0.5% | 100 mL | 10 mL | 90 mL | 10x |
Stock Solution Dilution Guide
Planning Reliable Dilutions
Stock dilution is a task in teaching labs, research benches, and quality rooms. A small arithmetic error can waste reagent, change assay response, or create unsafe concentrations. This calculator keeps the common C1V1 relationship visible while adding practical checks for units, overage, and pipette rounding.
Start with a concentrated stock. Enter its strength and the desired working strength. Then enter the final volume you want to prepare. The tool converts compatible units to one base scale, solves the selected unknown, and returns the stock volume, diluent volume, dilution factor, and mixing ratio. You can also solve for the missing stock strength, target strength, or final volume.
Accuracy Notes
Advanced options help match real laboratory workflow. Overage adds extra prepared solution for dead volume, transfer loss, or repeat wells. Rounding lets you match a pipette step, such as 0.1 mL or 5 µL. The achieved concentration estimate shows how rounding may shift the true target. This is useful when very small stock volumes are requested.
Good dilution practice also needs judgement. Use clean glassware or calibrated plasticware. Add most of the diluent first when the stock is viscous or reactive. Mix gently, then bring the solution to final volume. Label the container with concentration, solvent, date, preparer, and hazards. Store the result according to reagent stability rules.
Records
The table below gives sample lab cases. They show simple molar dilution, mass concentration dilution, and percentage dilution. Keep concentration units within one family. Do not mix molarity with mass per volume unless a molecular weight conversion is done separately.
Use the downloads for documentation. The CSV file is helpful for spreadsheets and electronic lab notebooks. The PDF file gives a printable record for batch sheets. Always review critical preparations with a second person when work affects safety, clinical testing, production release, or expensive experiments.
For best results, record temperature, solvent identity, and batch number. These details make repeated work easier to audit. They also help explain small differences between theoretical and measured concentration. When a requested stock volume is below reliable pipette range, make an intermediate dilution first. That extra step often improves accuracy and reduces waste. Document the calculation source and approval initials.
FAQs
What does C1V1 equals C2V2 mean?
It means the amount of solute before dilution equals the amount after dilution. C1 and V1 describe the stock. C2 and V2 describe the final working solution.
Can I mix molarity and mg per mL?
Not directly. Molarity and mass concentration need molecular weight conversion first. Use one concentration family inside the calculator for reliable dilution results.
What is diluent volume?
Diluent volume is the amount of solvent added to the stock. It equals final volume minus stock volume. It may be water, buffer, media, or another solvent.
Why add overage?
Overage prepares extra solution for transfer loss, tube dead volume, priming, or repeated wells. It increases the planned final volume used in the calculation.
What does rounding step do?
Rounding step adjusts the stock volume to a practical pipette increment. The calculator then estimates the achieved concentration after that rounded transfer.
When should I make an intermediate dilution?
Make one when the required stock volume is too small to pipette accurately. Intermediate dilution improves measurement control and reduces relative transfer error.
Can this calculator solve for stock concentration?
Yes. Choose stock concentration as the unknown. Then enter stock volume, target concentration, and final volume. The tool calculates the required stock strength.
Are PDF and CSV exports saved automatically?
No. They download when selected. CSV is useful for spreadsheets. PDF is useful for printable lab records, review sheets, and batch documentation.