Peptide Calculator: Dosage, Reconstitution & Syringe Units
This peptide calculator converts mg to mL and insulin units (IU) to help you accurately calculate peptide dosage, reconstitution, and injection volume.
Quick Start Instructions
- Pick Find Units or Find Dose.
- Enter vial size and water volume.
- Enter your dose, or use
Weight-Based Dose if needed.
- Choose syringe size.
- Add schedule and supply details for cycle planning and reorder timing.
- Export, print, or share your results.
Enter the number of units (IU marks) you will draw on your syringe, along with your vial and reconstitution details, to find the exact dose in mcg.
This calculator is provided for informational and research-use reference only. It does not constitute medical advice and is not a prescription tool. Users are responsible for independently verifying all calculations, protocol details, and product information before use.
Calculator data is processed locally in your browser for generating results, exports, and share links.
For research-use reference only. This is not medical advice.
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How to Use the Peptide Dosage Calculator
This peptide dosage calculator converts a vial's peptide strength and your bacteriostatic water volume into the exact number of insulin syringe units to draw for a target dose. It works for any research peptide, from BPC-157 and TB-500 to GHK-Cu, semaglutide, and growth hormone secretagogues, because every calculation comes back to one number: concentration in mg/mL.
Step 1: Choose Find Units or Find Dose
Use Find Units when you know your target dose in mcg and need to know how many syringe units to draw. Use Find Dose when you know the units you plan to draw and want the resulting dose. Most people reconstituting a fresh vial start with Find Units.
Step 2: Enter vial size and water volume
Enter the peptide strength printed on the mg vial (5, 10, 15, or 20 mg presets, or a custom amount) and the volume of bacteriostatic water you added during reconstitution (1, 2, or 3 mL, or custom). These two values set the concentration, the strength per mL that every dose depends on. A 5 mg vial in 2 mL of bacteriostatic water gives 2.5 mg/mL. If you are new to this step, the reconstitution logic here matches the worked examples in our peptide reconstitution guide.
Step 3: Use weight-based dosing if your protocol calls for it
Some protocols specify a dose per kilogram of body weight rather than a fixed dose. Turn on Weight-Based Dose, enter body weight in kg and the target in mcg/kg, and the calculator returns the total dose. A 91 kg person at 5 mcg/kg gets roughly 455 mcg. Leave this off for fixed dosing.
Step 4: Enter your dose or units
In Find Units, enter the desired dose in mcg. In Find Dose, enter the units on your syringe. The calculator returns the result for the active mode and shows it on a visual insulin syringe so you can confirm the pull against the markings on the barrel.
Step 5: Match your syringe size
Select the syringe you are actually holding: 0.3 mL (30 units), 0.5 mL (50 units), or 1 mL (100 units). A 0.5 mL syringe holds 50 units, not 100, and applying a calculation built for the wrong barrel is one of the most common dosing errors. The syringe diagram rescales to match.
Plan the full cycle
This part is optional. Beyond a single dose, the calculator plans the whole protocol. Set a dosing frequency, start date, and the number of vials you bought, and it projects how long your supply lasts and when to reorder so a peptide solution does not run out mid-cycle. You can export the schedule to your calendar, print a summary, or share a saved setup by link. These planning sections stay collapsed until you need them, so the core dosage math stays front and center.
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Browse Trusted VendorsPeptide Reconstitution Calculator: Common Volumes
While almost any volume of bacteriostatic water can be used, a few standard reconstitution amounts make peptide dosing more consistent and easier to measure.
2 mL (Most Common)
- A balanced option that works well for most peptides. It keeps concentrations manageable while maintaining reasonable injection volumes and is commonly used with standard 5 mg vials.
1 mL (Higher Concentration)
- Produces a stronger solution with smaller injection volumes. This approach can improve efficiency but may make precise dosing slightly more difficult, especially for beginners.
3 mL (Lower Concentration)
- Creates a more diluted solution, making small dose adjustments easier and more precise. However, it results in larger injection volumes.
For most people working with a standard 5 mg peptide vial, starting with 2 mL of bacteriostatic water provides a practical balance between concentration and dosing accuracy.
Want a full walkthrough of how to
reconstitute peptides safely?
Read the complete guide:
Peptide Reconstitution Guide
Peptide-Specific Dosing Guidelines
These are general reference ranges provided for calculator context. Detailed protocols vary and should be evaluated separately.
Worked Dosing Examples
These show how the calculator handles the situations people ask about most.
Stacking two peptides in one injection. When you combine compounds such as CJC-1295 and Ipamorelin, calculate each peptide separately, then draw them into the same syringe one after the other while tracking the total volume. Run each peptide through the calculator on its own before combining.
Weight-based dosing. Some protocols specify a dose per kilogram of body weight. A 200 lb person is about 91 kg, so at 5 mcg/kg the target dose is roughly 455 mcg. Turn on Weight-Based Dose in the calculator above and it converts that to syringe units for you.
Estimating how long a vial lasts. At 250 mcg twice daily from a 5 mg vial (5,000 mcg), you use 500 mcg per day, which is 10 days per vial. The Cycle Supply section projects this automatically and flags your reorder date.
Avoiding Common Peptide Dosing Mistakes
Peptides typically cost $50 to $200 per vial, so a single dosing error either wastes expensive compound or throws off your results for an entire cycle. Most mistakes come from the math, not the peptide. These are the errors the calculator is built to prevent, and the ones to watch for when you check your inputs.
Confusing milligrams with micrograms. There are 1,000 micrograms in 1 milligram. Enter a dose in milligrams when you meant micrograms and you will be off by a factor of 1,000. Confirm which unit each field expects before you draw.
Mismatching your syringe size. A 0.5 ml syringe holds 50 units, not 100. Apply a calculation built for a 1 ml (100 unit) syringe to a smaller one and the volume you draw will be wrong. Select the syringe size that matches the one in your hand.
Letting rounding errors stack up. If the result says draw 8.7 units and you round to 9 every time, you take about 3% more peptide per dose. Over weeks that changes both your results and how long the vial lasts. Use the number the calculator gives you.
Reconstituting with too little water. A higher concentration means a smaller injection volume, but it also makes precise dosing harder. For most 5 mg vials, 2 ml of bacteriostatic water is the practical balance between concentration and accuracy.
Skipping refrigeration. This is not a math error, but it has the same effect. A reconstituted peptide left unrefrigerated degrades quickly, so a correctly measured dose can still deliver less active compound than you calculated. Bacteriostatic water extends stability; refrigeration keeps it.
If two calculators give you different numbers for the same inputs, the gap usually comes down to how each one rounds and handles units. We explain
why two calculators can give different answers so you know which result to trust.
The Science Behind Peptide Dosing
Peptide dosing follows pharmacokinetic principles. Each compound has a half-life that determines how long it stays active, so shorter half-life peptides are typically dosed more frequently to hold a steady level.
Receptor saturation also matters. Once the target receptors are fully occupied, additional peptide adds no further effect, which is why precision matters more than volume and why more is not always better.
Individual response varies. Age, body composition, metabolic rate, and other compounds all influence how a given dose behaves. The calculator keeps your dose consistent so you can identify your own optimal amount through careful adjustment rather than guesswork.
Route of administration affects how much compound reaches circulation. Subcutaneous injection, the most common method, generally falls in the range of 80 to 95% bioavailability depending on the peptide. The calculator works from the dose you draw; your individual response determines the rest. If you want to see the arithmetic behind these conversions worked out in full, our
guide to the step-by-step dosage math walks through each calculation.
Peptide Preparation, Reconstitution, and Storage Basics
Calculator accuracy depends on proper preparation. How you reconstitute, dilute, and store a peptide sets its concentration, which is what every dose calculation relies on.
For step-by-step guidance, see:
Key Terms for Peptide Calculations
Peptide calculations typically involve converting between milligrams (mg), milliliters (mL), and insulin units (IU). Understanding how these units relate is essential for accurate dosing.
Peptide Strength (mg)
The total amount of peptide in the vial before reconstitution.
Bacteriostatic Water (mL)
The volume of liquid added to dissolve the peptide.
Concentration (mg/mL)
The strength of your solution after reconstitution, and the value every dose calculation depends on. See how dilution volume sets your concentration for the full breakdown.
Insulin Units (IU)
The measurement used on insulin syringes. This calculator converts your dose into units for accurate measurement. For a deeper breakdown of concentration and dilution, see the
Peptide Reconstitution Guide.
Calculating Peptide Doses for Pets
Peptide dosing for pets follows the same concentration principles as human dosing, but requires greater precision due to smaller body weights and tighter dosing ranges.
Most veterinary peptide use is calculated based on weight, which makes accurate reconstitution and unit conversion even more important. Small variations in measurement can have a larger relative impact compared to standard dosing scenarios.
This peptide calculator can be used for pets by adjusting inputs carefully, but for a dedicated weight-based tool designed specifically for animals, use the
Pet Peptide Calculator.
Bookmark this page to keep accurate peptide calculations available whenever you need them.
Peptide Calculator FAQ
What does the peptide calculator do?
The calculator estimates either the syringe units needed for a target dose or the dose delivered by a set number of syringe units. It also handles weight-based dosing, schedule planning, cycle supply tracking, reorder projections, calendar export, sharing, and a print or save summary.
What is the difference between Find Units and Find Dose?
Use Find Units when you already know the dose in mcg and want to calculate how many syringe units to draw. Use Find Dose when you already know the syringe units and want to estimate the resulting dose in mcg.
How do I use weight-based dosing?
Turn on Weight-Based Dose, then enter body weight in kilograms and the target dose in mcg per kg. The calculator will automatically generate a computed total dose from those two values.
Can I use custom vial sizes and water volumes?
Yes. The calculator includes preset buttons for common vial sizes and water volumes, but it also provides custom input fields for both values if your setup does not match a preset option.
What syringe sizes does the calculator support?
The calculator supports 0.3 ml, 0.5 ml, and 1 ml syringes, which correspond to 30, 50, and 100 unit scales. The syringe diagram rescales to match the size you select and the number of units calculated.
How does the dosing schedule feature work?
The Dosing Schedule section lets you set a frequency, start date, and time of day, with optional cycle end and manual end dates. You can pick a preset frequency such as daily, twice daily, every other day, or a weekly pattern, or set a custom schedule.
How does the calculator estimate reorder timing?
The Cycle Supply and Cycle Timeline sections use your starting vial count, vial size, dose, and dosing schedule to estimate how long supply may last. The reorder date is then projected using the depletion date minus the reorder buffer in days.
Can I export my schedule to a calendar?
Yes. Once you enter valid schedule details, the Download Calendar File and Add Calendar Reminder buttons become active and let you add your dosing schedule to your calendar.
Can I save or share my calculation?
Yes. The calculator includes Print / Save Summary for printing or saving as PDF, plus share tools for copying, emailing, or sharing a completed setup.
Important Disclaimer:
This peptide calculator is provided for research and educational purposes only and does not constitute medical advice, diagnosis, or treatment.
Assumption of Risk: Use of this calculator and any actions you take based on its results are at your own risk. We make no warranties regarding accuracy and are not liable for any damages, injuries, or losses arising from use of this tool.
Regulatory Notice: Many peptides are for research use only and may not be FDA-approved for human use. Verify the legal status in your jurisdiction.
Individual results vary. Never disregard professional medical advice or delay seeking it because of information on this website. In case of emergency or adverse reaction, seek immediate medical attention.