Last updated: October 2026
Deca Dosage Calculator
Quick answer: A 200 mg/week dose over 1 shots from a 200 mg/mL vial is 1 mL (100 units) per shot, ≈ 128 mg active hormone/week. mL = (weekly mg ÷ shots) ÷ mg/mL.
Injectable ester — about 64% of each mg is Deca; the calculator converts dose → mL, units and active mg. Aromatizes: Partial / weak. Liver-strain (17α-alkylated): No. Half-life: ≈ 6–12 days oil-depot.
About this calculator
Deca-Durabolin is the long-ester form of nandrolone. Only about 64% of each milligram is active nandrolone — the long decanoate chain accounts for the rest and the slow release. This calculator converts a weekly dose into draw volume and syringe units, and shows the multi-day depot half-life.
Deca-Durabolin is nandrolone on the long decanoate ester — the slow counterpart to NPP. It is commonly supplied at 200 mg/mL, and only about 64% of each milligram is the parent hormone, the lowest of the nandrolones here.
How the injection-volume maths works
The long decanoate chain makes up over a third of the molecule’s weight (274.4 ÷ 428.6 = 0.64), so a 200 mg dose delivers about 128 mg of nandrolone. The calculator shows both the labelled dose and the active figure.
How to use this calculator
Enter your weekly dose, the concentration printed on your vial (mg/mL), and how many injections per week. The result updates instantly with the mL to draw, the U-100 syringe units, and the active-hormone milligrams delivered.
Worked examples
Weekly dose: 200 mg · Concentration: 200 mg/mL · Injections/week: 1
200 mg/shot ÷ 200 = 1 mL (100 units) · active ≈ 128 mg/week
Weekly dose: 300 mg · Concentration: 300 mg/mL · Injections/week: 2
150 mg/shot ÷ 300 = 0.5 mL (50 units) · active ≈ 192 mg/week
Deca dose chart
Common doses at 200 mg/mL, 2 injections/week (each row is the calculator’s arithmetic worked out):
| Weekly dose | mL/shot | Units | Active/week |
|---|---|---|---|
| 100 mg | 0.25 mL | 25 | 64 mg |
| 150 mg | 0.375 mL | 37.5 | 96 mg |
| 200 mg | 0.5 mL | 50 | 128 mg |
| 300 mg | 0.75 mL | 75 | 192 mg |
| 400 mg | 1 mL | 100 | 256 mg |
Half-life & clearance
Illustrative single-dose elimination by half-life (t½ ≈ 9 days). Each marker is one half-life; after ~5 the dose is essentially cleared. For an oil depot the real rise-and-fall is slower (absorption-limited release), so treat this as a timing reference, not a blood-level prediction.
With a multi-day (~6–12 day) depot, Deca is injected infrequently and takes weeks to reach steady state; free nandrolone clears in hours once released (Minto 1997). Its metabolite is among the longest-detectable of any steroid.
How to interpret your result
The result is the volume to draw per injection and its mark on a U-100 syringe. The active-hormone figure shows how much actual Deca that ester delivers — useful when comparing esters or switching concentrations. The half-life figure is a pharmacokinetic timing reference only.
Aromatization, liver & monitoring
Like NPP, nandrolone aromatizes weakly but is markedly progestogenic. It is not 17α-alkylated, so liver strain is not the main concern — but lipids, prolactin and recovery of natural testosterone are.
Common mistakes
Expecting fast results is the common mistake; the long ester means levels build slowly over weeks. For the maths, remember the active fraction is 0.64 — lower than most esters.
Deca at a glance
| Property | Deca |
|---|---|
| Form | Injectable (oil/suspension) |
| Active fraction | 0.64 (esterFactor) |
| Half-life | ≈ 6–12 days oil-depot — canonical nandrolone monograph; free nandrolone clears in ~4.3 h |
| Aromatizes | Partial / weak — same as NPP; mainly progestogenic. |
| Liver (17α-alkylated) | No (not 17α-alkylated). |
| Approx. detection | Very long — 19-norandrosterone detectable for months (one of the longest of any AAS). |
Deca ester and half-life
Deca is nandrolone on a ten-carbon decanoate chain. The chain makes up over a third of the molecule, so the active factor is 274.4 ÷ 428.6, which rounds to 0.64, the lowest of the nandrolone esters here. The oil depot has a half-life of roughly 6 to 12 days according to the canonical nandrolone monograph, so a fixed weekly amount takes weeks to level off. Once the ester is cleaved, free nandrolone itself clears in about 4.3 hours (Minto 1997), and the 19-norandrosterone marker stays detectable for months.
Deca dose range in mL and units
The reference range for Deca runs from 100 mg to 400 mg a week. Split into 2 shots, that is 50 mg to 200 mg per shot. At 200 mg/mL that is 0.25 mL to 1 mL per shot, or 25 to 100 units on a U-100 syringe. At 300 mg/mL that is 0.167 mL to 0.667 mL per shot, or 16.7 to 66.7 units on a U-100 syringe. Each shot carries 32 mg to 128 mg of active nandrolone, which is the shot multiplied by 0.64. These are conversions of the numbers shown, not a recommendation.
Deca injection volume notes
Deca is commonly supplied at 200 mg/mL, with 300 mg/mL as the stronger option. At 200 mg/mL one full millilitre holds 200 mg, so a 200 mg shot is exactly 1 mL, or 100 units, the top mark of a 1 mL insulin syringe. The 300 mg/mL vial reaches that same 1 mL at 300 mg. Because decanoate is a slow ester, the first worked example puts the whole week into a single shot, and the second divides a larger week into two. A U-100 syringe is marked in whole units of 0.01 mL, so a result with a decimal has to be read to the nearest mark; the extra decimal in the table shows how far that rounding moves the draw.
Deca worked examples
| Example | Weekly dose | Vial | Shots/week | mg per shot | mL per shot | Units | Active per shot |
|---|---|---|---|---|---|---|---|
| Deca example 1 | 200 mg | 200 mg/mL | 1 | 200 mg | 1 mL | 100 | 128 mg |
| Deca example 2 | 300 mg | 300 mg/mL | 2 | 150 mg | 0.5 mL | 50 | 96 mg |
| Deca example 3 | 400 mg | 200 mg/mL | 2 | 200 mg | 1 mL | 100 | 128 mg |
Deca questions answered
Frequently asked questions
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References
- Minto CF et al. Pharmacokinetics and pharmacodynamics of nandrolone esters in oil vehicle. J Pharmacol Exp Ther 1997;281(1):93–102 (PMID 9316843)
- PubChem — nandrolone (molecular weight), CID 9904
- PubChem — nandrolone decanoate (molecular weight), CID 9677
- Kicman AT. Pharmacology of anabolic steroids. Br J Pharmacol 2008;154(3):502–521
Every citation URL was verified to return HTTP 200. Citations are provided for transparency and education and do not imply the cited authors or bodies endorse this tool. Anabolic steroid use carries real health risks — always consult a qualified clinician.
How this is calculated
For injectables the calculator divides your weekly dose by the number of injections, then by the vial concentration, to get the mL per shot — and multiplies by 100 for U-100 syringe units (1 mL = 100 units). The active-hormone milligrams are the dose multiplied by the esterFactor (the parent hormone’s molecular weight divided by the full ester’s molecular weight, both from PubChem). For orals it divides the daily dose by your doses-per-day and tablet strength to get tablets per dose. Half-life timing uses ke = ln2 ÷ t½ and the ~5-half-life rule of thumb for steady state and clearance. It is arithmetic only — nothing you enter is stored or sent anywhere, and the result is not medical advice or an endorsement of anabolic steroid use.