Peptide Calculator
Dosage, reconstitution, and syringe-unit math for 30+ peptides. Free, no account, no tracking.
Enter your vial, your bacteriostatic water, and your target dose. The calculator converts it into syringe units in real time.
Reconstitution calculator
Show the math
Enter values above to see the step-by-step math.
Free Illustrated Reconstitution Guide (PDF)
8-step visual walkthrough with photos and tips — from gathering supplies to drawing your dose. Educational only — not medical advice.
Peptide dosage calculator
A peptide dosage calculator converts a target dose — usually in milligrams or micrograms — into the exact number of units to draw on a syringe. The math is simple dimensional analysis: once you know the concentration of your reconstituted vial (mg per mL), you divide your target dose by that concentration to get a volume, then convert that volume into syringe units based on the scale of your insulin syringe (U-100 or U-40). The calculator above does every step in real time and flags draws that are too large for the syringe barrel or too small to read accurately.
Peptide reconstitution calculator
Reconstitution is the process of mixing a lyophilized peptide with bacteriostatic water to produce an injectable solution. The reconstitution calculator above takes your vial size and the amount of bacteriostatic water you add and returns the resulting concentration. That concentration feeds the dosage calculation: mg per mL times your draw volume gives you the mass per injection. Entering vial, water, and dose together lets the same tool serve both reconstitution and dosage workflows without switching screens.
Calculators by peptide
Each calculator is pre-filled with a common vial size for that peptide and includes factual, non-promotional information about vial sizes, reported half-life, and storage.
GLP-1 Agonists
Healing & Recovery
Growth Hormone Secretagogues
Cosmetic
Longevity & Metabolic
Peptide classes
Browse by receptor class or therapeutic category.
Popular peptide stacks
Combinations commonly referenced in online peptide communities.
Peptide blends (multi-peptide vials)
Some vendors sell pre-mixed vials containing two or more peptides in a single lyophilized powder. Blend calculators handle the proportional math — target a total blend dose or back-calculate a specific component dose.
Not one of these? Use the generic blended-vial calculator →
How peptide dosage math works
Every dosage calculation comes down to two conversions:
Step 1: concentration. Divide the peptide mass (in mg) by the volume of bacteriostatic water added (in mL). A 5 mg vial mixed with 1 mL of water produces a 5 mg/mL solution, or 5,000 mcg/mL.
Step 2: draw volume. Divide your target dose (converted to mcg) by the concentration in mcg/mL. The result is the volume in mL you need to draw. Multiply that volume by the units-per-mL of your syringe (100 for U-100, 40 for U-40) to get the number of marked units to draw to.
That's it. No magic — just dimensional analysis. The calculator above automates these steps and flags two safety conditions: when the required draw would exceed the syringe's capacity, and when the required volume is too small to measure accurately.
Common mistakes
The most frequently reported sources of math errors in published user discussions and research protocols.
- Confusing mg and mcg. 1 mg = 1,000 mcg.
- Confusing U-100 and U-40 syringes. Same physical volume, different scales. A "10 unit" mark on a U-40 syringe is 2.5× the volume of a "10 unit" mark on a U-100.
- Under-diluting a potent peptide. Very small draw volumes are hard to measure accurately.
- Over-diluting a less potent compound. If your required draw exceeds the syringe barrel, switch to a larger syringe.
- Forgetting to label the vial. Write the reconstitution date and concentration the moment you mix it.
Free Peptide Dosage Cheat Sheet (PDF)
Free Illustrated Reconstitution Guide (PDF)
8-step visual walkthrough with photos and tips — from gathering supplies to drawing your dose. Educational only — not medical advice.
Peptide calculator FAQ
What is a peptide calculator? +
How do I calculate my peptide dosage? +
What's the difference between dosage and reconstitution? +
What syringe do I use for peptides? +
How do I convert mg to units on a syringe? +
What is GLP-1? +
What are peptide stacks? +
Do I need different math for U-100 vs U-40 syringes? +
Guides
Long-form educational articles on reconstitution, insulin syringe markings, bacteriostatic water, storage, and more.