Peptide Calculator

Calculate dosage, BAC water reconstitution, and syringe units for any peptide — instantly.

Peptide Dosage Calculator

Enter 3 values — get instant results

For research use only

Select Peptide — auto-fills common values (optional)

1 Vial Size mg

Printed on vial label (e.g. 5 mg, 10 mg)

2 BAC Water mL

Bacteriostatic water added to vial

3 Target Dose mcg

Per injection in mcg (e.g. 250 mcg for BPC-157)

S Syringe Size mL

Select syringe — affects unit markings shown

GetPeptideCalc.com — Peptide Dosage Results

DRAW VOLUME

—

milliliters

UNITS

—

U-100 scale

CONCENTRATION

—

mg / mL

DOSES / VIAL

—

total injections

i How to use: Enter your vial size and the amount of bacteriostatic water you will add. Then enter your desired dose to see exactly how much to draw.

★ Tip: 1 mL = 100 units on an insulin syringe. Draw slowly to ensure accuracy. For GLP-1 peptides like Tirzepatide, switch the dose toggle to mg.

1 mL · 100 units

—

units

— mL

i How to use: Enter your vial size and the amount of bacteriostatic water you will add. Then enter your desired dose to see exactly how much to draw.

★ Tip: 1 mL = 100 units on an insulin syringe. Draw slowly to ensure accuracy. For GLP-1 peptides like Tirzepatide, switch the dose toggle to mg.

Water Solver — How much BAC water should I add?

Know your vial size and desired syringe units? This reverse calculator tells you exactly how much bacteriostatic water to add.

Vial Size (mg)

Desired Dose (mcg)

Target Syringe Units

For educational and research purposes only. Not medical advice. Always consult a qualified professional before use. Reviewed by a BS Bioinformatics graduate, PIEAS.

Works with: BPC-157 Semaglutide Retatrutide Tirzepatide GHK-Cu TB-500 CJC-1295 + 100 more

Quick Start

How to Use the Peptide Calculator

The peptide calculator requires 3 inputs to calculate the injection volume, syringe units, concentration, and doses per vial.

Enter Vial Size (mg)

Find the total peptide amount printed on the vial label and enter it in milligrams. Common sizes include 2 mg, 5 mg, 10 mg, and 15 mg. Use the quick-select buttons for speed.

Enter BAC Water (mL)

Enter the volume of bacteriostatic water you added to the vial in milliliters. Most researchers add 1 mL to 3 mL. Adding 2 mL to a 10 mg vial gives a clean 5,000 mcg/mL concentration.

Enter Target Dose (mcg)

Enter your desired dose per injection in micrograms. BPC-157 is typically dosed at 200–500 mcg. Semaglutide starts at 250 mcg. Tirzepatide starts at 2,500 mcg (2.5 mg = 2,500 mcg).

Read Your Results

The calculator instantly outputs 4 values: draw volume in mL, syringe units on a U-100 insulin syringe, solution concentration in mcg/mL, and total doses per vial.

Reference Data

Peptide Dosage Reference Table

The amount of fluid to draw from any reconstituted vial comes down to two numbers: how much powder is in the vial and how much bacteriostatic water was added. Dividing the vial size in milligrams by the water volume in milliliters gives the concentration, the number of milligrams dissolved in every milliliter of solution.

A 5 mg vial filled with 2 mL of bacteriostatic water produces a concentration of 2.5 mg/mL (2,500 mcg/mL). A 10 mg vial filled with the same 2 mL produces 5 mg/mL (5,000 mcg/mL). Once the concentration is known, the draw volume in milliliters is the target dose divided by the concentration. Multiplying that draw volume by 100 converts it to tick marks on a standard U-100 insulin syringe, where each tick equals exactly 0.01 mL.

The table below pre-calculates these values for the 3 most common lyophilized powder vial sizes, 2 mg, 5 mg, and 10 mg, all reconstituted with 2.0 mL of bacteriostatic water, across 2 standard dose levels each.

Vial Size	BAC Water	Concentration	Target Dose	Draw Volume	Syringe Units
2 mg Vial	2.0 mL	1,000 mcg/mL	250 mcg	0.25 mL	25 Ticks
2 mg Vial	2.0 mL	1,000 mcg/mL	500 mcg	0.50 mL	50 Ticks
5 mg Vial	2.0 mL	2,500 mcg/mL	250 mcg	0.10 mL	10 Ticks
5 mg Vial	2.0 mL	2,500 mcg/mL	500 mcg	0.20 mL	20 Ticks
10 mg Vial	2.0 mL	5,000 mcg/mL	500 mcg	0.10 mL	10 Ticks
10 mg Vial	2.0 mL	5,000 mcg/mL	1,000 mcg	0.20 mL	20 Ticks

Definition

What is a Peptide Calculator?

A peptide calculator is a digital tool that calculates the exact injection volume in milliliters from the known concentration of a reconstituted peptide solution.

The tool accepts 3 measurements, vial peptide content in milligrams, diluent volume in milliliters, and target dose in micrograms, and outputs the draw volume on a standard U-100 insulin syringe. Peptide calculators eliminate manual calculation errors that occur when converting between milligrams, micrograms, and milliliters.

A concentration of 5,000 mcg/mL from a 10 mg vial reconstituted in 2 mL of bacteriostatic water means a 500 mcg dose requires drawing 0.10 mL, or 10 units on a U-100 syringe. Calculating this manually across repeated doses introduces dosing inconsistency that a peptide dosage calculator eliminates in under one second.

// Peptide Dosage Formula

Concentration (mcg/mL) = Vial (mg) × 1,000 ÷ BAC Water (mL)
Draw Volume (mL) = Target Dose (mcg) ÷ Concentration (mcg/mL)
Syringe Units = Draw Volume (mL) × 100
Doses Per Vial = Vial (mg) × 1,000 ÷ Target Dose (mcg)

What is Peptide Reconstitution?

Peptide reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide powder into a liquid solvent to produce an injectable solution. Peptides arrive as white lyophilized powders in sealed glass vials because the dry form is stable during shipping and long-term storage at temperatures between −20°C and −80°C.

What is Bacteriostatic Water?

Bacteriostatic water is a sterile water solution containing 0.9% benzyl alcohol as a preservative. The benzyl alcohol inhibits bacterial growth after reconstitution, extending the usable life of the peptide solution to 28 days when stored at 2°C to 8°C. Sterile water contains no preservative and must be used within 24 hours.

Step-by-Step

How to Reconstitute Peptides: 6 Steps

Proper peptide reconstitution maintains peptide integrity and ensures accurate dosing across the full vial.

Gather Supplies

Collect the lyophilized peptide vial, bacteriostatic water vial, 2 insulin syringes (1 mL, U-100), and 2 alcohol swabs. Ensure the workspace surface is clean and dry.

Sterilize Both Vials

Clean both vial tops with separate alcohol swabs and allow 30 seconds for the alcohol to evaporate completely before inserting any needle.

Draw the BAC Water

Draw the calculated volume of bacteriostatic water into the first insulin syringe. For most peptides, 1 mL to 3 mL produces a measurable, precise concentration. Use the calculator above to confirm your target volume.

Inject Water Into Peptide Vial

Inject the bacteriostatic water slowly into the peptide vial by aiming the syringe at the inside wall of the vial, not directly onto the powder. This prevents foaming and peptide degradation from direct mechanical force.

Dissolve — Do Not Shake

Gently swirl the vial between your palms for 30–60 seconds until the powder dissolves completely. Never shake the vial — shaking creates mechanical stress that denatures peptide bonds and reduces potency.

Store at 2°C to 8°C

Store the reconstituted vial upright in a refrigerator at 2°C to 8°C. Use within 28 days for bacteriostatic water, or within 24 hours for sterile water. Label the vial with the reconstitution date.

Equipment Guide

Syringe Types for Peptide Injection

Peptide injections use 3 standard insulin syringe sizes. Each has a different unit scale. The calculator above defaults to U-100 units.

U-100 Syringe (1 mL) — Most Common

Holds 1 mL total. Has 100 unit markings. Each unit equals 0.01 mL. This is the standard syringe for most peptide research protocols. A draw of 10 units delivers 0.10 mL.

U-50 Syringe (0.5 mL)

Holds 0.5 mL total. Has 50 unit markings. Wider spacing between marks gives improved precision for small draw volumes under 0.25 mL. Ideal for high-concentration solutions where doses are under 5 units on U-100.

U-30 Syringe (0.3 mL)

Holds 0.3 mL total. Has 30 unit markings. Best precision for very small doses. Used when the calculated draw volume is under 0.15 mL and precision below 3 units is required.

Luer Lock (1 mL or 2 mL)

Graduated in 0.01 mL increments. Used when draw volumes exceed 1 mL or when a detachable needle is required. Read the markings in mL directly, no unit conversion is needed.

FAQs

Common Peptide Calculator Questions

What is the Difference Between a Peptide Dosage Calculator and a Reconstitution Calculator?

A peptide dosage calculator determines how much solution to draw from an already-reconstituted vial based on the target dose. A reconstitution calculator determines how much bacteriostatic water to add to a dry peptide vial to achieve a target concentration. This page provides both functions in a single tool — enter vial size, BAC water, and target dose to get all 4 output values simultaneously.

How Much Bacteriostatic Water Should I Add to a Peptide Vial?

The standard bacteriostatic water volume for peptide reconstitution is 1 mL to 3 mL per vial. Adding 2 mL to a 10 mg vial produces a concentration of 5,000 mcg/mL, which places a 500 mcg dose at exactly 10 units on a U-100 syringe — a clean, precise measurement. Using less water increases concentration and reduces draw volume per dose, which improves precision on very small doses. Using more water decreases concentration and increases draw volume, which makes mid-range doses easier to measure.

Can this Peptide Calculator be Used for Semaglutide and Tirzepatide?

Yes. The peptide calculator works for all injectable peptides, including GLP-1 receptor agonists such as semaglutide (Ozempic, Wegovy), tirzepatide (Zepbound, Mounjaro), and retatrutide. Enter the vial size in mg, the BAC water volume in mL, and the target dose in mcg. For tirzepatide, note that doses are commonly expressed in mg — convert to mcg by multiplying by 1,000 before entering (e.g. 2.5 mg = 2,500 mcg).

What Does mcg/mL Mean on a Peptide Solution?

mcg/mL (micrograms per milliliter) is the concentration of a reconstituted peptide solution. A concentration of 2,500 mcg/mL means each 1 mL of solution contains 2,500 mcg of peptide. Drawing 0.10 mL from this solution delivers 250 mcg. The peptide calculator computes this concentration automatically from vial size and water volume and displays it as one of the 4 output values.

How Many Doses are in a 10 mg Peptide Vial at 500 mcg Per Dose?

A 10 mg vial contains 10,000 mcg of peptide. At 500 mcg per dose, the vial contains exactly 20 doses. The peptide calculator displays the total doses per vial as one of 4 output values — enter vial size 10, BAC water 2, and dose 500 to confirm.

Is this Peptide Calculator Accurate for BPC-157?

Yes. BPC-157 is a synthetic pentadecapeptide of 15 amino acids with a molecular weight of 1,419.53 daltons. The dosage calculation for BPC-157 uses the same mass-volume formula as all other peptides. A standard BPC-157 protocol of 250 mcg from a 5 mg vial reconstituted in 2 mL BAC water requires drawing 0.10 mL (10 units on U-100). The dedicated BPC-157 calculator page provides protocol-specific dosing tables and reconstitution guides for this compound.

What Peptides Does this Calculator Support?

The peptide dosage calculator works for all injectable research peptides, including BPC-157, TB-500, GHK-Cu, CJC-1295, Ipamorelin, Sermorelin, AOD 9604, Hexarelin, Semaglutide, Tirzepatide, Retatrutide, Epithalon, PT-141, Selank, Semax, Melanotan II, KLOW blend, GLOW blend, KPV, NAD+, and all other lyophilized peptides sold in mg vials. If it comes as a powder that is reconstituted with bacteriostatic water, this calculator handles the math.

What is the Peptide Calculator Formula?

The peptide calculator uses a 3-step concentration formula. Step 1: Concentration (mcg/mL) = Vial Size (mg) × 1,000 ÷ BAC Water (mL). Step 2: Draw Volume (mL) = Target Dose (mcg) ÷ Concentration (mcg/mL). Step 3: Syringe Units (U-100) = Draw Volume (mL) × 100. Doses Per Vial = Vial Size (mg) × 1,000 ÷ Target Dose (mcg).

Can I Use this Calculator for Peptide Blends Like KLOW?

This single-compound calculator calculates dosage based on one peptide per vial. KLOW is a 4-peptide blend (GHK-Cu, BPC-157, TB-4, KPV) in a fixed mass ratio. For KLOW and other peptide blends, use the dedicated Blend Calculator page, which accepts multi-compound vials and calculates the dose of each individual peptide per injection.

Why is my Draw Volume More Than 1 mL?

A draw volume exceeding 1 mL means your target dose exceeds the capacity of a standard 1 mL U-100 syringe. This occurs when the concentration is low (e.g. too much BAC water added) or the target dose is very high relative to vial size. Solutions: use less BAC water to increase concentration, reduce the target dose, or use a 2 mL luer lock syringe to accommodate the full draw volume.

More Tools

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Reconstitution Calculator

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Blend Calculator

Individual doses from KLOW, GLOW & multi-peptide vials

Accumulation Calculator

Model peptide buildup over a dosing cycle by half-life

BPC-157 Calculator

Protocol-specific dosage & reconstitution for BPC-157

Retatrutide Calculator

GLP-1/GIP/glucagon tri-agonist weekly dosing calculator

Semaglutide Calculator

Ozempic & Wegovy dosing and syringe draw calculator

About This Tool

Reconstitution Calculator

The dosage formulas and reference data on this site are based on standard mass-concentration-volume calculations used in biochemistry and pharmacology research. Content is developed and reviewed by a researcher with a BS degree in Bioinformatics (16 years of formal education), with graduate research in MYC gene network analysis in Lung Adenocarcinoma at HU.

BS Bioinformatics

Molecular Research

Gene Network Analysis

Compound Index