Steroid Conversion Calculator

Steroid Conversion Calculator for Endocrinology. The output is an anti-inflammatory-equivalent dose, not an identical drug. Two doses being equivalent on this scale does not mean equivalent duration of action or mineralocorticoid effect: hydrocortisone and cortisone are short-acting (8-12 h) with substantial sodium retention; prednisone/methylprednisolone are intermediate (12-36 h); dexamethasone and betamethasone are long-acting (36-72 h) with essentially no mineralocorticoid activity. When converting away from hydrocortisone/cortisone toward dexamethasone, remember you are also removing mineralocorticoid support, which matters in primary adrenal insufficiency. Round to practical tablet strengths and reassess clinically rather than treating the number as exact.

How this calculator works

This tool converts a dose of one systemic corticosteroid into the equivalent dose of another using published relative glucocorticoid (anti-inflammatory) potency ratios anchored to hydrocortisone. The core arithmetic is: equivalent dose = starting dose x (starting drug potency / target drug potency), where potency is expressed relative to hydrocortisone = 1. Standard oral/IV equivalence: hydrocortisone 20 mg = cortisone 25 mg = prednisone/prednisolone/methylprednisolone... (prednisone 5 mg, methylprednisolone 4 mg, triamcinolone 4 mg) = dexamethasone 0.75 mg = betamethasone 0.6 mg. The calculator handles the glucocorithoid axis only; it does not scale mineralocorticoid activity, which diverges sharply across agents.

When to use this calculator

Use when switching a patient between systemic corticosteroids (e.g. IV methylprednisolone to oral prednisone at hospital discharge, or converting to dexamethasone for its long half-life and low mineralocorticoid effect). It is designed for anti-inflammatory/immunosuppressive dosing. Do NOT use it for physiologic adrenal replacement dosing (where hydrocortisone 15-25 mg/day split to mimic diurnal cortisol is standard and equivalence tables mislead), for inhaled, intra-articular, or topical steroids (bioavailability differs entirely), or as a stress-dose calculator.

Inputs used

  • Current corticosteroid
  • Current dose
  • Target corticosteroid
  • Route and clinical context

Clinical interpretation

The output is an anti-inflammatory-equivalent dose, not an identical drug. Two doses being equivalent on this scale does not mean equivalent duration of action or mineralocorticoid effect: hydrocortisone and cortisone are short-acting (8-12 h) with substantial sodium retention; prednisone/methylprednisolone are intermediate (12-36 h); dexamethasone and betamethasone are long-acting (36-72 h) with essentially no mineralocorticoid activity. When converting away from hydrocortisone/cortisone toward dexamethasone, remember you are also removing mineralocorticoid support, which matters in primary adrenal insufficiency. Round to practical tablet strengths and reassess clinically rather than treating the number as exact.

Worked example

A patient on IV methylprednisolone 40 mg is being switched to oral prednisone. Methylprednisolone relative potency = 5, prednisone = 4. Equivalent prednisone dose = 40 x (5/4) = 50 mg. To instead convert 40 mg methylprednisolone to dexamethasone (potency 25-30): 40 x (5/27) is roughly 7.4 mg, so about 6-8 mg dexamethasone daily delivers comparable anti-inflammatory effect but with a much longer duration of action and negligible sodium retention.

Limitations and safety notes

Potency ratios are population averages from classic pharmacology data, not individualized: interindividual variation in absorption, protein binding, and 11-beta-HSD/CYP3A4 metabolism means the true equivalent dose varies. Prednisone and cortisone are prodrugs requiring hepatic activation (to prednisolone and cortisol), so equivalence assumes normal liver function. The tool does not adjust for enzyme inducers/inhibitors, hypoalbuminemia, pregnancy (where prednisolone is preferred as placenta metabolizes it and dexamethasone crosses freely), or the differing HPA-suppression risk of long-acting agents. It says nothing about how to taper: abrupt switching between agents does not address adrenal recovery.

Frequently asked questions

Why does prednisone convert to dexamethasone at roughly 6.7:1?

Because dexamethasone is about 25-30 times as potent as hydrocortisone and prednisone about 4 times, the ratio is roughly 27/4, so prednisone 5 mg is equivalent to dexamethasone 0.75 mg. Dexamethasone also lasts far longer (36-72 h), so equivalent anti-inflammatory dosing produces more sustained HPA suppression.

Is methylprednisolone stronger than prednisone?

Slightly, on the anti-inflammatory scale: methylprednisolone relative potency is 5 versus 4 for prednisone, so 4 mg methylprednisolone equals 5 mg prednisone. Methylprednisolone also has essentially no mineralocorticoid activity, which is why it is often chosen for pulse and IV therapy.

Can I use this for hydrocortisone replacement in Addison disease?

No. Adrenal replacement targets physiologic cortisol (about 15-25 mg hydrocortisone daily in divided doses) and requires separate mineralocorticoid (fludrocortisone) cover. Anti-inflammatory equivalence tables overestimate what a patient needs for replacement and ignore the diurnal rhythm and salt-retaining requirement.

Does an equivalent dose let me stop the old steroid immediately?

Switching preserves anti-inflammatory effect but does not protect against adrenal insufficiency from prior chronic use. Per the 2024 ESE/Endocrine Society guideline, taper faster while supraphysiologic and slower near physiologic doses; the calculator does not design the taper.

Why isn't mineralocorticoid effect in the calculation?

Mineralocorticoid potency does not track anti-inflammatory potency. Hydrocortisone retains sodium meaningfully while dexamethasone does not, so converting between them on the glucocorticoid axis can silently drop or add salt-retaining activity that must be managed separately.

References

  • Beuschlein F, Else T, Bancos I, et al. European Society of Endocrinology and Endocrine Society Joint Clinical Guideline: Diagnosis and Therapy of Glucocorticoid-induced Adrenal Insufficiency. J Clin Endocrinol Metab. 2024;109(7):1657-1683. PMID: 38724043.
  • Beuschlein F, Else T, Bancos I, et al. European Society of Endocrinology and Endocrine Society Joint Clinical Guideline: Diagnosis and therapy of glucocorticoid-induced adrenal insufficiency. Eur J Endocrinol. 2024;190(5):G25-G51. PMID: 38714321.

Editorial review and citation methodology

Reviewed by the Quick Medical Calculator Editorial Team. Last reviewed: June 6, 2026. The review checks calculator inputs, intended population, interpretation, limitations, and source alignment.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.

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