SDS-PAGE Polyacrylamide Gel Mix Calculator
Enter your target gel chemistry to calculate exact reagent volumes for one mixed gel solution. APS and TEMED should always be added last.
Educational use only. Always follow your lab SOP, institutional safety rules, and validated protocol.
What this polyacrylamide gel calculator does
This calculator helps you quickly prepare polyacrylamide gel solutions for SDS-PAGE by calculating how much acrylamide stock, Tris buffer, SDS, APS, TEMED, and water to combine for a target final volume.
Instead of repeatedly doing dilution math by hand, you can set your desired percentages and concentrations and get a clean recipe in both mL and µL. This is especially useful when preparing multiple gel percentages throughout a long day of protein work.
How the calculation works
Each component is calculated from the dilution formula:
C1V1 = C2V2
- C1 is the stock concentration
- V1 is the stock volume to add (what we solve for)
- C2 is the desired final concentration
- V2 is total final gel volume
Water is then calculated as:
Water = Final Volume − (Acrylamide + Tris + SDS + APS + TEMED)
Typical SDS-PAGE targets
| Gel type | Typical acrylamide % | Typical Tris final | Main use |
|---|---|---|---|
| Stacking gel | 4% | 0.125 M (pH 6.8) | Concentrate proteins into sharp bands |
| Resolving gel | 8–10% | 0.375 M (pH 8.8) | Larger proteins |
| Resolving gel | 12% | 0.375 M (pH 8.8) | General-purpose protein separation |
| Resolving gel | 15% | 0.375 M (pH 8.8) | Smaller proteins and peptides |
Step-by-step workflow in the lab
1) Choose gel chemistry
Select stacking or resolving preset, then set the target acrylamide percentage based on your protein molecular-weight range.
2) Enter final volume
Estimate enough mix for your cassette size plus slight excess to avoid bubbles or partial fills.
3) Calculate and prepare
- Combine water, Tris, acrylamide, and SDS first
- Degas if needed (especially for large batches)
- Add APS and TEMED last to start polymerization
- Pour immediately after adding initiators
4) Let polymerize fully
Do not disturb the gel while it sets. Polymerization time depends on APS/TEMED levels and room temperature.
Practical tips for better gel consistency
- Use fresh APS. Old APS is a common reason for slow or incomplete polymerization.
- Protect acrylamide solutions from light and heat to preserve quality.
- Mix gently after adding APS/TEMED to avoid introducing excess oxygen.
- If you see irregular polymerization, check pH, reagent freshness, and pipetting accuracy.
- Always verify your gel recipe against your validated lab protocol.
Safety notes
Unpolymerized acrylamide is neurotoxic. Wear gloves, lab coat, and eye protection. Work in designated areas and dispose of waste according to institutional and regulatory requirements. This calculator is an aid, not a substitute for training or SOPs.
FAQ
Can I use this for native PAGE?
The dilution math still applies, but native PAGE recipes differ in buffer composition and detergent use. Adjust to your protocol accordingly.
Why does the calculator show an error sometimes?
If a desired final concentration is equal to or greater than the stock concentration, the required volume is impossible. Lower the target or use a stronger stock.
How much TEMED should I use?
TEMED is usually added in very small volumes. Use your lab standard first. The default in this calculator is a common starting point, not a universal rule.
Bottom line
A reliable polyacrylamide gel starts with precise preparation. This calculator speeds up setup, reduces arithmetic mistakes, and helps standardize runs across experiments. For publishable work, always anchor your final recipe to validated methods and quality controls.