What is a peptide reconstitution calculator?

A peptide reconstitution calculator works out how much bacteriostatic water to add to a lyophilised peptide vial and how many units to draw on a graduated syringe for a target amount per aliquot in laboratory research.

How do I use the peptide reconstitution calculator?

Enter your vial size in mg, the amount of bacteriostatic water you plan to add in ml, and the target amount per aliquot in mg. Choose your syringe size (0.3ml, 0.5ml or 1ml). The calculator returns concentration in mcg/ml, the exact volume per aliquot and the units to draw on the syringe.

How much bac water do I use?

There is no single correct volume — more water gives a lower concentration and larger draw. Common laboratory choices are 1ml, 2ml or 3ml of bacteriostatic water per 10mg vial. Match volume to syringe size so your target aliquot lands on a clear graduation mark.

How many units is 0.25mg on a 1ml syringe?

It depends on concentration. With a 10mg vial reconstituted in 2ml of bacteriostatic water (5,000mcg/ml), 0.25mg equals 0.05ml, which is 5 units on a 1ml (100 unit) graduated syringe.

Is the peptide calculator free?

Yes. The peptide reconstitution calculator is completely free, needs no sign-up, and runs entirely in your browser.

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Free laboratory tool

Peptide Reconstitution Calculator

Free reconstitution calculator for in vitro laboratory research. Enter vial size, bacteriostatic water volume and target amount per aliquot — get concentration, draw volume and graduated syringe units instantly. Works for any lyophilised research peptide. No sign-up, works on mobile.

For In Vitro Research Use Only — Not for Human or Veterinary Use

This tool performs concentration and volume mathematics for laboratory reconstitution only. It provides no guidance on administration, and no output from it should be interpreted as a recommendation for human or animal use.

Vial size (mg)

Bacteriostatic water (ml)

Target amount per aliquot (mg)

Syringe size

Peptide reconstitution calculator — how it works

Our reconstitution calculator uses the standard laboratory formula: concentration (mcg/ml) = vial mg × 1000 ÷ bacteriostatic water ml. Divide your target amount per aliquot (mcg) by that concentration to get the exact draw volume in millilitres, then convert to syringe units. Works for every lyophilised research peptide reconstituted with bacteriostatic water.

Worked example

A 10mg vial reconstituted with 2ml of bacteriostatic water gives 5,000mcg/ml. For a 0.25mg (250mcg) target aliquot that’s 0.05ml — 5 units on a 1ml (100u) graduated syringe. Change any input above and the calculator recalculates instantly.

Quick reference: units per aliquot (1ml / 100u syringe)

Vial	Bac water	Concentration	1mg aliquot	0.25mg aliquot
5mg	1ml	5,000 mcg/ml	20 units	5 units
5mg	2ml	2,500 mcg/ml	40 units	10 units
10mg	2ml	5,000 mcg/ml	20 units	5 units
10mg	3ml	3,333 mcg/ml	30 units	7.5 units
20mg	2ml	10,000 mcg/ml	10 units	2.5 units
30mg	3ml	10,000 mcg/ml	10 units	2.5 units
40mg	3ml	13,333 mcg/ml	7.5 units	1.9 units

Halve the units on a 0.5ml (50u) syringe scale reading, or use the calculator above for exact figures.

mg, mcg and units — what the numbers mean

1mg = 1,000mcg. “Units” on a graduated syringe are a volume scale, not a strength: on a 1ml syringe 100 units = 1ml, so 1 unit = 0.01ml. That is why the same 250mcg aliquot can be 5 units or 10 units depending on how much bacteriostatic water you added. Always calculate units from your own concentration — never copy someone else’s unit count.

Choosing your bacteriostatic water volume

Pick a volume that puts your typical aliquot between roughly 5 and 40 units so it lands on a readable graduation mark. Smaller volumes concentrate the peptide and reduce draw error on very small aliquots; larger volumes make micro-aliquots easier to measure. Reconstituted vials are generally kept refrigerated and used within the supplier’s stated window.

Which research peptides does the calculator support?

BPC-157 & TB-500
GHK-Cu copper peptide
Ipamorelin, CJC-1295, Tesamorelin
MT-1, MT-2, PT-141
Retatrutide, Tirzepatide, Semaglutide (research reference material)
Any lyophilised research peptide

Peptide reconstitution calculator UK — FAQs

How much bacteriostatic water should I add?: There is no single correct volume. More water = lower concentration = larger draw. Common laboratory choices are 1ml, 2ml or 3ml per 10mg vial — match to your syringe so aliquots land on a clear graduation.
Does the calculator work for graduated syringes?: Yes — pick 0.3ml (30u), 0.5ml (50u) or 1ml (100u) above and the output converts your draw volume into units directly on the barrel.
Does it work for BPC-157 and other research peptides?: The same reconstitution maths applies to BPC-157, TB-500, GHK-Cu and any lyophilised research peptide. Enter your vial mg, bacteriostatic water ml and target amount per aliquot in mg.
Where do I buy the research peptides and bac water?: Browse UK-stocked, HPLC 99%+ purity research peptides in our shop, grab bacteriostatic water (3ml & 10ml), or read the peptide reconstitution guide.

For In Vitro Use Only — Not for Human Use

All products sold by Peptides UK 4U are supplied strictly for in vitro laboratory research purposes. They are not for human use, veterinary use, diagnostic or therapeutic use, or cosmetic application.