How it's calculated
Each corticosteroid's approximate equivalent glucocorticoid dose to 20 mg hydrocortisone is used as a potency reference (e.g. 5 mg prednisone, 0.75 mg dexamethasone). The converted dose scales proportionally between the two selected drugs' reference values.
Approximate equivalent doses (glucocorticoid potency)
| Drug | Equivalent to 20 mg hydrocortisone |
|---|---|
| Hydrocortisone | 20 mg |
| Cortisone acetate | 25 mg |
| Prednisone / Prednisolone | 5 mg |
| Methylprednisolone / Triamcinolone | 4 mg |
| Dexamethasone | 0.75 mg |
| Betamethasone | 0.6 mg |
Clinical use
- This conversion covers glucocorticoid (anti-inflammatory) potency only — it does not account for mineralocorticoid activity, which differs substantially between these drugs (hydrocortisone and cortisone have meaningful mineralocorticoid effect; dexamethasone and betamethasone have essentially none).
- Duration of action also differs considerably — hydrocortisone and cortisone are short-acting, prednisone/prednisolone and methylprednisolone are intermediate-acting, and dexamethasone/betamethasone are long-acting, which affects dosing frequency independent of the potency conversion.
- These are approximate equivalency ratios from standard references — individual patient response can vary, and doses should be titrated to clinical effect rather than relying on the conversion alone for fine dose adjustments.
- When switching a patient on long-term or high-dose steroids, consider both the potency-equivalent dose and any need for a tapering schedule to avoid adrenal insufficiency from abrupt discontinuation.
Frequently asked questions
What is the steroid conversion calculator used for?
It estimates an equivalent anti-inflammatory (glucocorticoid) dose when switching a patient from one corticosteroid to another, using standard published potency-equivalence ratios.
Does this account for mineralocorticoid effects?
No — this conversion is for glucocorticoid (anti-inflammatory) potency only. Hydrocortisone and cortisone have meaningful mineralocorticoid (salt-retaining) activity that dexamethasone and betamethasone largely lack, which matters separately for conditions like adrenal insufficiency.
Why do dexamethasone and prednisone have such different mg doses for the same effect?
Different corticosteroids have different intrinsic potencies at the glucocorticoid receptor — dexamethasone is roughly 25-30 times more potent by weight than hydrocortisone, which is why its equivalent doses are much smaller in absolute mg terms.
Can I use this to directly switch a patient's steroid dose?
It gives a reasonable estimated equivalent dose as a starting point, but duration of action, mineralocorticoid activity, and individual patient factors also need to be considered — and any taper should follow a clinician's plan rather than a single dose conversion.
References
- Liu D, et al. A practical guide to the monitoring and management of the complications of systemic corticosteroid therapy. Allergy Asthma Clin Immunol. 2013;9:30.
- British National Formulary (BNF) — Glucocorticoid Therapy, Equivalent Doses.
- Meikle AW, Tyler FH. Potency and duration of action of glucocorticoids. Am J Med. 1977;63:200-207.