Peptide calculator methodology
Purpose of the peptide calculator methodology
This peptide calculator methodology documents the equations, unit definitions, validation rules, display precision, and deliberate limits used across Peptide Calc. The website performs dimensional arithmetic after a user supplies total vial mass, liquid volume, and a target mass. It does not derive a medically appropriate target, select a product, recommend a liquid, or provide instructions for administration. Publishing the method makes each output reproducible instead of asking users to trust a hidden formula.
The calculation runs locally in the browser. Inputs are parsed as positive decimal numbers and are not submitted to a server. The same calculation module is used by the visible tool and automated tests, reducing the risk that test formulas differ from production formulas. The peptide calculator methodology applies to the general, reconstitution, dosage, syringe-unit, and compound-labeled calculator pages.
1. Normalize mass to micrograms
The vial field uses milligrams. The target field accepts milligrams or micrograms. Before calculating concentration, vial milligrams are multiplied by 1,000 to obtain micrograms. If the target is entered in milligrams, it is also multiplied by 1,000. If the target is already in micrograms, its numerical value is retained.
NIST defines milli as 10⁻³ and micro as 10⁻⁶. Therefore, one milligram equals exactly one thousand micrograms. The peptide calculator methodology does not support an approximate conversion factor or infer units from the number’s size. The user must explicitly select mg or mcg, and the normalized target appears in the displayed equation.
vial mcg = vial mg × 1,0002. Calculate concentration
Concentration connects mass and volume. Total vial mass in micrograms is divided by the entered liquid volume in milliliters. The result is micrograms per milliliter. The interface also divides that value by 1,000 to display milligrams per milliliter. Both describe the same concentration.
The peptide calculator methodology treats entered liquid volume as the actual volume used for the mathematical scenario. It does not decide how much liquid should be added. Product-specific selection depends on authoritative instructions outside this site. Zero or negative liquid values are rejected because division by zero is undefined and negative physical volume is invalid for this model.
concentration mcg/mL = vial mcg ÷ liquid mL3. Calculate target volume
Target volume is calculated by dividing normalized target mass by concentration. The unit cancellation is explicit: mcg divided by mcg/mL leaves mL. This is why target mass cannot be converted directly into syringe volume without first knowing concentration.
When the target mass is larger than the total vial mass, the mathematical result can still be computed, but the interface displays a warning. It does not silently cap the target, alter the vial amount, or pretend the entered scenario contains enough total mass. This behavior is part of the peptide calculator methodology because warnings should preserve user inputs while identifying a contradiction.
draw mL = target mcg ÷ concentration mcg/mL4. Express volume on a U-100 scale
U-100 is modeled as 100 marked units per milliliter. Official DailyMed labeling documents this 100 units/mL relationship. The calculated target volume is multiplied by 100, so 0.01 mL maps to 1 unit, 0.05 mL maps to 5 units, and 0.1 mL maps to 10 units on that scale.
The peptide calculator methodology uses U-100 only as a relationship between marked units and volume. It does not describe peptide activity in insulin units or international units. Other syringe scales are outside the current model. A result above 100 units is flagged because it exceeds the one-milliliter visual range, even though the raw arithmetic remains visible.
U-100 units = draw mL × 1005. Calculate theoretical amounts per vial
Theoretical amounts per vial equal total vial mass divided by target mass. A 10,000 mcg vial divided by a 250 mcg target produces 40 mathematical amounts. This output does not estimate usable yield. It ignores dead space, material left in a vial or syringe, transfer loss, manufacturing tolerances, overfill, underfill, damage, and stability.
The label “calculated amounts” is intentional. It is not a treatment schedule, number of administrations, duration, or claim that every fraction can be measured. The peptide calculator methodology keeps that value secondary to concentration and volume to reduce the chance that a theoretical division is mistaken for product or medical guidance.
Precision, formatting, and validation
Internal arithmetic uses JavaScript numbers without rounding between steps. Formatting is applied only when values are displayed. Syringe markings use up to two decimal places, draw volume uses up to four, concentration uses up to three, and the mathematical amount count uses up to two. Trailing zeros are removed for readability. Displaying a decimal does not imply that a physical device can measure to that precision.
Automated tests cover a standard calculation, a target entered in milligrams, a target beyond total vial mass, a volume above one milliliter, invalid values, bidirectional mg/mcg conversion, and number formatting. Production builds also run TypeScript checks. The peptide calculator methodology is reviewed when formula behavior, units, warnings, or supported scales change.
Sources and limits
Unit definitions come from NIST SI guidance. The U-100 scale relationship is documented in official DailyMed labeling. The site also links to Bacteriostatic Water for Injection labeling and CDC injection-safety guidance to make clear that product and procedural safety extend beyond arithmetic.
The peptide calculator methodology cannot validate product identity, purity, sterility, labeling, storage, compatibility, route, equipment, a target amount, or a person’s medical circumstances. Read the medical disclaimer and obtain qualified, product-specific guidance before using any result in a health-related context. Last reviewed: 2026-07-30.