Cost Per mg Calculator

A price belongs to a transaction, not to a substance. The same peptide in a 5 mg vial and in a much larger container carries two different prices, and neither number means anything on its own, because what a buyer actually wants to know is what the material costs per unit of material. Dividing by the mass is what converts a transaction into a property. The mass is the right denominator because it is the quantity a vial label quantifies, so a figure built on it scales with the amount rather than with the packaging.

The result is therefore independent of how much you buy. If a unit price is constant, a single vial and a bulk order return the same cost per milligram, which means the number is measuring the material and not the deal. That is exactly what makes it usable as a comparison figure: two suppliers offering the same peptide in different pack sizes can be placed on one basis by dividing, without either figure being converted into the packaging of the other. A number that shifted with order size would be measuring the seller instead of the substance.

The mass you divide by must be the mass of active substance, not the mass in the container. Those are the same number only for pure material. Anything present alongside the peptide, whether counterions, residual solvent or a salt form, contributes to a gross figure without contributing to the amount of peptide actually present. Cost per milligram of gross mass is therefore lower than cost per milligram of active substance by exactly the fraction that is not peptide. Where a purity figure exists, correcting for it is a single division, and the purity correction calculator performs that step on its own.

Purity and unit price interact in a direction that surprises people: impure material looks cheaper per milligram on gross mass and then costs more per milligram of the substance actually of interest. That is why two containers at visibly different prices can have identical cost per milligram of active substance, and why a more precisely specified material can appear to be the more expensive one. Where no purity figure is available the honest move is to leave the correction out and record that the result is a gross mass figure, rather than to assume a purity. The recovery percent calculator runs the same reasoning in the opposite direction.

Cost per milligram prices the material and nothing else. Shipping, diluent, syringes, filters, time and the portion of a container that goes unused are all excluded, and on a small order they can rival the vial price. A material with the best unit price is therefore not automatically the cheapest route to a given amount of peptide. The batch cost calculator exists to hold the list of everything that is not the substance, precisely so that the unit price reads as one component of a total rather than as the total itself.

Unused material changes the arithmetic in a specific and quantifiable way. If a container is opened and only part of its contents is used, the price paid covers the whole labelled mass while the amount actually used is smaller, so the effective cost per milligram used is the label figure divided by the smaller number. How much larger that is depends entirely on the fraction consumed, which turns it into an input rather than an opinion. The cost per sample calculator carries the same idea up one level, dividing a whole batch by the number of samples it yields, which is the form that survives an uneven split.

Once a cost per milligram exists, every other cost figure on the site is one multiplication or division away. The cost of a given amount is the unit price times that amount. The cost of a whole vial is the unit price times the labelled mass. The cost per micromole needs the mass expressed as a particle count first, which is what the cost per micromole calculator does. Working from the unit price rather than from raw prices keeps all of these figures mutually consistent, which is the real reason to compute it once.

Two identities are worth checking, because both are exact and both catch transcription errors. Multiply a cost per milligram by the total mass and the original price comes back. Multiply a cost per micromole by the total micromoles and the original price comes back as well. When either fails, the fault is in an input rather than in the arithmetic, and finding that out before a purchase is far cheaper than finding it out afterwards. The cost calculator starts from a single vial and reports the cost of an amount drawn from it, which is an independent route to the same arithmetic.