SDS-PAGE Acrylamide Gel Mix Calculator
Enter your desired gel parameters, then click Calculate Mix to generate a master mix recipe.
Tip: APS and TEMED should be added last, immediately before pouring the gel.
What this acrylamide gel calculator does
This calculator helps you quickly prepare SDS-PAGE gel solutions by converting target final concentrations into practical pipetting volumes. Instead of manually re-doing dilution math each time, you enter your gel size and stock concentrations, and it returns a full master mix recipe (including acrylamide/bis, Tris buffer, SDS, APS, TEMED, and water).
It is designed for common laboratory workflows where you cast one or more resolving or stacking gels. You can also add an overage percentage so you do not run short while pouring.
How the calculator works
1) Dilution principle
For each reagent, the required volume is calculated from: Vstock = Vfinal × (Cfinal / Cstock). The calculator applies this equation to acrylamide, Tris, SDS, and APS.
2) TEMED calculation
TEMED is usually added as a small volume percent of the final mix. The calculator converts your requested % v/v directly into a volume: VTEMED = Vfinal × (%TEMED / 100).
3) Water back-fill
Water volume is computed last as: Vwater = Vfinal − (sum of all other components). If water becomes negative, your concentration choices are not physically feasible and must be adjusted.
Common gel setups
| Gel Type | Typical % Acrylamide | Typical Tris System | Use Case |
|---|---|---|---|
| Stacking gel | 4% | 0.5 M stock to 0.125 M final (pH ~6.8) | Compresses samples into sharp bands before separation |
| Resolving gel | 8–15% | 1.5 M stock to 0.375 M final (pH ~8.8) | Separates proteins by size |
| High-% resolving gel | 15%+ | As above | Better for smaller proteins/peptides |
Practical casting workflow
- Prepare all stocks fresh and confirm concentrations.
- Use this calculator to generate a master mix with 5–15% overage.
- Combine water, buffer, SDS, and acrylamide first.
- Add APS and TEMED last, mix gently, and pour immediately.
- Overlay resolving gel with isopropanol/water if needed, then cast stacking gel after polymerization.
Troubleshooting quick guide
Gel does not polymerize
Check APS freshness (it degrades quickly), verify TEMED addition, and confirm stock identities. Old APS is one of the most common causes of failed polymerization.
Bands are distorted or smiling
Common causes include overheating, uneven polymerization, high salt samples, or running conditions that are too aggressive. Ensure consistent gel composition and running temperature.
Poor resolution
Match gel percentage to expected molecular weights. Lower % gels resolve larger proteins better; higher % gels resolve smaller proteins better.
Final notes
This tool is intended for planning and convenience, not as a substitute for protocol validation. If your lab uses specific recipes, pH values, or polymerization conditions, treat those SOPs as primary. Still, having a reliable calculator reduces arithmetic errors and makes gel prep much faster—especially when scaling to multiple gels.