Peptide Calculator
Free peptide dosage & reconstitution calculator. Enter vial size, bac water and target dose — get concentration, draw volume and insulin syringe units instantly. Works for Retatrutide, Tirzepatide, Semaglutide, BPC-157, GHK-Cu, Ipamorelin and any research peptide. No sign-up, works on mobile.
Peptide dosage calculator — how it works
Our peptide dosage calculator uses the standard reconstitution formula: concentration (mcg/ml) = vial mg × 1000 ÷ bac water ml. Divide your target dose (mcg) by that concentration to get the exact draw volume in millilitres, then convert to insulin syringe units. Works for every research peptide reconstituted with bacteriostatic water.
Peptide reconstitution calculator — worked example
A 10mg vial reconstituted with 2ml of bacteriostatic water gives 5,000mcg/ml. For a 0.25mg (250mcg) dose that’s 0.05ml — 5 units on a 1ml (100u) insulin syringe. Change any input above and the peptide reconstitution calculator recalculates instantly.
Quick reference: units per dose (1ml / 100u syringe)
| Vial | Bac water | Concentration | 1mg dose | 0.25mg dose |
|---|---|---|---|---|
| 5mg | 1ml | 5,000 mcg/ml | 20 iu | 5 iu |
| 5mg | 2ml | 2,500 mcg/ml | 40 iu | 10 iu |
| 10mg | 2ml | 5,000 mcg/ml | 20 iu | 5 iu |
| 10mg | 3ml | 3,333 mcg/ml | 30 iu | 7.5 iu |
| 20mg | 2ml | 10,000 mcg/ml | 10 iu | 2.5 iu |
| 30mg | 3ml | 10,000 mcg/ml | 10 iu | 2.5 iu |
| 40mg | 3ml | 13,333 mcg/ml | 7.5 iu | 1.9 iu |
Halve the units on a 0.5ml (50u) syringe scale reading, or use the calculator above for exact figures.
mg, mcg and iu — what the numbers mean
1mg = 1,000mcg. “Units” (iu) on an insulin 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 dose 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 bac water volume
Pick a volume that puts your typical dose between roughly 5 and 40 units so it lands on a readable tick mark. Smaller volumes concentrate the peptide and reduce draw error on very small doses; larger volumes make micro-doses easier to measure. Reconstituted vials are generally kept refrigerated and used within the manufacturer’s stated window.
Which peptides does the peptide calc support?
- Retatrutide 10mg / 15mg / 30mg / 40mg
- Tirzepatide 20mg / 40mg / 60mg
- Semaglutide 5mg / 10mg
- BPC-157 (BPC 157 dosage calculator)
- TB-500 & BPC-157/TB-500 blend
- GHK-Cu 50mg / 100mg copper peptide
- Ipamorelin, CJC-1295, Tesamorelin
- MT-1, MT-2, PT-141, Melanotan
Peptide calculator UK — FAQs
- How much bac water should I add?
- There is no single correct volume. More water = lower concentration = larger draw. Common choices are 1ml, 2ml or 3ml per 10mg vial — match to your syringe so daily doses land on a clear tick.
- Does the peptide dose calculator work for insulin 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.
- Is this a BPC-157 dosage calculator?
- The same reconstitution maths applies to BPC-157, TB-500, GHK-Cu and any lyophilised research peptide. Enter your vial mg, bac water ml and target dose in mg.
- Where do I buy the 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.