Buffer Recipe Calculator
Scale a common molecular-biology buffer to any volume. Pick a recipe and enter the volume you want — the ingredient amounts are worked out for you.
To make 500 mL of 1X TBS (Tris-buffered saline):
- Tris base1.21 g
- Sodium chloride (NaCl)4 g
Target pH: 7.5
Dissolve in ~900 mL water, adjust to pH 7.5 with HCl, then top up to the final volume.
How it works
Lab buffers are defined by fixed concentrations, so the ingredient amounts scale linearly with the volume you make. This calculator holds canonical recipes for the most-used Western-blot and general buffers — TBS, TBST, PBS, PBST, and 5% milk or BSA blocking buffers — and multiplies each ingredient by your target volume.
Masses are given in grams and liquids in millilitres. Dissolve the solids in most of the water first, adjust to the target pH where noted, then top up to the final volume so the concentrations come out right. Blocking buffers are best made fresh.
Examples
- 500 mL of 1X TBS needs 1.21 g Tris base and 4 g NaCl.
- TBST is TBS plus 0.1% Tween-20 (1 mL per litre).
- 5% blocking buffer is 50 g of milk or BSA per litre of TBST.
Frequently asked questions
- How do buffer recipes scale?
- Linearly with volume — since the concentration is fixed, each ingredient is simply proportional to how much buffer you make.
- Why top up to volume after mixing?
- Dissolving solids changes the volume slightly. Adding water to the final mark after dissolving keeps the concentrations accurate.
- Milk or BSA for blocking?
- Non-fat milk is cheap and works for most antibodies; BSA is preferred for phospho-specific antibodies because milk contains phosphoproteins.
- Can I store these buffers?
- TBS and PBS keep well refrigerated; add Tween fresh if storing long-term. Blocking buffers with milk or BSA should be made fresh.