The Peptide Calculator

Unit converter

Mass and volume convert exactly. International units and molar amounts need one figure from elsewhere, and the converter asks for it rather than guessing.

Educational arithmetic only. Not medical advice and not a dosing protocol.

From the preparation’s own label. Needed only for an IU conversion.
Needed only for a molar amount. Sourced figures are on the compound pages.

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Read this with the answer

This is educational arithmetic on figures entered by the reader. It is not medical advice, not a dosing protocol, and not a recommendation that anything be prepared, obtained or administered.

Nothing here states what quantity is appropriate for anyone, and there is no function in it that produces an amount to administer. A question about anyone’s health belongs with a licensed clinician who can examine the person asking.

Most compounds named here are research chemicals that are not approved by the FDA for human use. An exact calculation is not an accurate measurement: what is actually in a syringe depends on the preparation and the device, neither of which this page can see.

No qualified clinical reviewer is recorded against this site, and no credential is claimed anywhere on it. Full disclaimer.

Show the working
  1. Mass and volume factors are exact integer ratios: 1 mg is 1,000 mcg, 1 mL is 1,000 microlitres, and no rounding happens on the way through.
  2. International units: mass in mg = IU / (IU per mg). The potency has to come from the preparation, because an international unit is defined against a biological reference standard per substance and has no universal mass equivalent.
  3. Molar amount: n = m / M, where M is the molar mass in grams per mole. 5 mg of a compound at 1,419.5 g/mol is 3,522.37 nanomoles.

Two of these four conversions need a fact this site cannot supply

Milligrams to micrograms is a definition and needs nothing from anybody. International units to milligrams is not. An international unit measures biological activity against a reference standard, the standard differs by substance, and the units-per-milligram figure belongs to the specific preparation it was measured in. A converter holding a built-in IU table is making a claim about a vial it has never seen.

Molar mass is a fact about a molecule rather than a preparation, so it is knowable, but it still has to come from a record rather than from a guess. Each of the compound pages carries one, with the PubChem record it was read from and the date it was retrieved. Compounds whose molar mass was not sourced have no page, rather than a page with a plausible number on it.

Why a molar amount is worth converting to at all

Mass is the unit everything is labelled in and the wrong unit for comparing two different compounds. One milligram of a 889 g/mol compound contains about 5.4 times as many molecules as one milligram of a 4,813 g/mol compound. If a quantity is being compared across compounds in any way, the molar amount is the figure that compares and the mass is not.

The comparison stops at molecule counts. Equal molar amounts are not equal potency, equal activity or equal anything else, and the answer says so every time it is produced.

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