How It Works

This calculator works in 4 steps.

Choose the input mode
Select ratio (1:X) or concentration (µg/mL from a known stock).
Enter the dilution
Type X from the protocol, or the stock and target µg/mL.
Enter the working volume
Type the buffer volume needed for the blot, slide, or plate.
Read the volumes
The calculator returns antibody and buffer volumes and the final µg/mL.

The Formula

The formula divides the working volume by the ratio term X.

Antibody volume (ratio) V_Ab = V_total / X

Antibody volume (concentration) V_Ab = C_target × V_total / C_stock

Final concentration C_final = C_stock / X

X:: Ratio term in 1:X (stock-to-final)
V_total:: Working volume
C_stock / C_target:: Stock and target antibody concentration

Worked example

A 1:2,000 dilution in 10 mL needs 5 µL antibody and 9,995 µL buffer. From a 1 mg/mL stock, the final concentration is 0.5 µg/mL.

Conversion Table

The conversion table gives antibody volumes for 10 mL and 5 mL and the final concentration from a 1 mg/mL stock for 7 ratios.

Dilution	Antibody in 10 mL	Antibody in 5 mL	Final µg/mL (1 mg/mL stock)
1:100	100 µL	50 µL	10 µg/mL
1:250	40 µL	20 µL	4 µg/mL
1:500	20 µL	10 µL	2 µg/mL
1:1,000	10 µL	5 µL	1 µg/mL
1:2,000	5 µL	2.5 µL	0.5 µg/mL
1:5,000	2 µL	1 µL	0.2 µg/mL
1:10,000	1 µL	0.5 µL	0.1 µg/mL

What Is the Antibody Dilution Calculator?

The Antibody Dilution Calculator is a tool that turns the dilution in your protocol, as 1:X or µg/mL, into antibody and buffer volumes. A 1:1,000 dilution in 10 mL of buffer needs 10 µL of antibody.

Data sheets give a starting dilution for each use. For example, 1:1,000 for a western blot or 1:100 for tissue stains. The best dilution changes by lot and sample. So the calculator uses the one you choose and does not pick one for you. When the stock concentration is known, the calculator states the final antibody concentration in µg/mL.

Common Uses

There are 5 main uses of this calculator.

Western blot
Users dilute antibodies in 5% milk or BSA for membrane incubation.
Immunohistochemistry (IHC)
Pathology labs dilute antibodies for tissue sections.
Immunofluorescence (IF)
Cell biologists dilute antibodies for slide staining.
ELISA
Assay developers dilute capture and detection antibodies.
Flow cytometry
Users dilute antibodies per test volume, such as 100 µL.

Antibody Dilution Calculator