Last updated: June 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.

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. esterFactor = 274.4 ÷ 428.6 = 0.64 (active Deca fraction).

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 example

Worked example — injectable

Weekly dose: 200 mg · Concentration: 200 mg/mL · Injections/week: 1

200 mg/shot ÷ 200 = 1 mL (100 units) · active hormone ≈ 128 mg/week

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. The half-life figure is a pharmacokinetic timing reference only. For oil depots it is the absorption-limited release of the ester, not the cleared parent hormone.

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
Aromatises	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).

Frequently asked questions

How do I calculate my Deca dose?

Divide your weekly dose by the number of injections, then by the vial concentration: mL = (weekly mg ÷ shots) ÷ mg/mL, and × 100 for U-100 syringe units. The calculator above does this instantly.

What is the active-hormone amount for Deca?

Deca is an ester, so only part of each milligram is hormone. Its esterFactor is 0.64 (parent MW 274.4 ÷ ester MW 428.6), so a 100 mg dose delivers about 64 mg of the parent hormone.

What is the half-life of Deca?

≈ 6–12 days oil-depot — canonical nandrolone monograph; free nandrolone clears in ~4.3 h.

Does it aromatise or stress the liver?

Aromatises: Partial / weak — same as NPP; mainly progestogenic. 17α-alkylated (liver strain): No (not 17α-alkylated).

Is this medical advice?

No. This is an educational arithmetic tool. It converts the numbers you enter, stores nothing, and does not recommend any dose, cycle, or protocol. Anabolic steroid use carries real health risks — consult a qualified clinician.

Choose a compound

Testosterone Cypionate Anavar (Oxandrolone) Trenbolone Dianabol (Methandrostenolone) NPP (Nandrolone Phenylpropionate) Turinabol (Tbol) Deca (Nandrolone Decanoate) Winstrol (Stanozolol) Equipoise (Boldenone Undecylenate)

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References

Citations are provided for transparency and education. They 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. 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). For orals it divides the daily dose by your doses-per-day and tablet strength to get tablets per dose. 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.