💉 Injection Volume Calculator
Convert dose and concentration to the exact mL and syringe unit mark — with U-100 and U-40 support and precision warnings.
Finding Your Exact Draw Volume
Once your vial is reconstituted, the only maths left is: given your desired dose and the solution concentration you created, how many millilitres do you draw — and which unit mark does that correspond to on your specific syringe?
The most dangerous mistake in peptide research is syringe type confusion. A U-40 syringe has 40 units per mL (1 unit = 0.025 mL). A U-100 syringe has 100 units per mL (1 unit = 0.01 mL). If you use U-100 unit counts on a U-40 syringe, you inject 2.5× the intended dose. This calculator shows your unit count for both syringe types and displays a clear safety warning when U-40 is selected.
You want 300 mcg Ipamorelin. Your vial is at 1,500 mcg/mL on a U-100 syringe.
- Enter 300 mcg as the desired dose
- Enter 1,500 mcg/mL as the concentration
- Volume = 300 ÷ 1,500 = 0.2 mL
- U-100 units: 0.2 × 100 = draw to the 20-unit mark
- U-40 units: 0.2 × 40 = draw to the 8-unit mark
Injection Volume Calculator
Enter your dose and solution concentration. Switch syringe type to see the correct unit mark for your syringe.
How to draw your dose accurately
- Clean the vial stopper with an alcohol swab
- Draw air equal to your dose volume into the syringe
- Insert needle into the vial, inject the air
- Invert the vial and pull the plunger to the unit mark shown above
- Tap to remove air bubbles, push them back into the vial
Injection Volume — Frequently Asked Questions
What is the difference between U-100 and U-40 syringes?
The "U" number indicates how many units of insulin fit in 1 mL. A U-100 syringe: 100 units/mL, so 1 unit = 0.01 mL. A U-40 syringe: 40 units/mL, so 1 unit = 0.025 mL. For peptide research, U-100 syringes are strongly preferred because smaller unit increments allow finer dose control. U-40 syringes are primarily used in veterinary contexts. If you accidentally use U-40 unit counts on a U-100 syringe, each unit delivers 0.4× less volume — you under-dose by 60%. The reverse (U-100 counts on U-40) causes a 2.5× overdose.
My volume is less than 0.05 mL — is that OK?
No. Volumes below 0.05 mL (5 units U-100) are too small to draw reliably. A one-unit error at 5 units is a 20% dosing mistake. The solution is to dilute your peptide further — use the Reconstitution Calculator's BAC Water Optimizer to find how much water puts your dose at a comfortable 0.2 mL (20 units).
What syringe size should I use for subcutaneous peptide injections?
A 29–31 gauge, 0.5 inch (12.7 mm) needle on a 0.5 mL or 1 mL U-100 insulin syringe is ideal for subcutaneous peptide injections. The short fine needle minimises pain and is the correct depth for SC tissue. Avoid needles longer than 5/8 inch for SC injections — they risk hitting muscle (intramuscular), which changes absorption kinetics.
Can I split a large dose into two injections?
Yes — if your dose requires more than 0.5–1.0 mL per injection, splitting across two sites is best practice. Subcutaneous injections above 1.0 mL at a single site can cause localised discomfort, bruising, and slower absorption. Common split-dose sites: left and right abdomen (1–2 cm from the navel), or abdomen and thigh. Use a fresh needle for each injection.