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Loop diuretic equivalence calculator (furosemide, torsemide, bumetanide)

Converts a dose of furosemide, torsemide, bumetanide or ethacrynic acid, oral or IV, into the approximately equivalent dose of another loop diuretic. The result is a starting estimate, not a prescription.

  • Conversions
  • Label tables
  • Runs on your device

Short answer

Loop diuretic doses are compared through units of 40 mg oral furosemide: the equivalent amounts are furosemide oral 40 mg and IV 20 mg, torsemide 20 mg oral or IV, bumetanide 1 mg oral or IV, and ethacrynic acid 50 mg oral or IV (Brater 1998; Felker 2020).

Loop diuretic equivalence

Runs on your device. Nothing you enter is saved or sent.

Estimate only. Interpret it with the patient's clinical picture and the product label.

Sources

8
  1. Brater DC. Diuretic therapy. N Engl J Med. 1998;339(6):387–395. DOI 10.1056/NEJM199808063390607 PubMed 9691107
  2. Felker GM, Ellison DH, Mullens W, Cox ZL, Testani JM. Diuretic therapy for patients with heart failure: JACC state-of-the-art review. J Am Coll Cardiol. 2020;75(10):1178–1195. DOI 10.1016/j.jacc.2019.12.059 PubMed 32164892
  3. Shankar SS, Brater DC. Loop diuretics: from the Na-K-2Cl transporter to clinical use. Am J Physiol Renal Physiol. 2003;284(1):F11–F21. Later adaptation DOI 10.1152/ajprenal.00119.2002 PubMed 12473535
  4. Vargo DL, Kramer WG, Black PK, Smith WB, Serpas T, Brater DC. Bioavailability, pharmacokinetics, and pharmacodynamics of torsemide and furosemide in patients with congestive heart failure. Clin Pharmacol Ther. 1995;57(6):601–609. DOI 10.1016/0009-9236(95)90222-8 PubMed 7781259
  5. Mentz RJ, Anstrom KJ, Eisenstein EL, et al. Effect of torsemide vs furosemide after discharge on all-cause mortality in patients hospitalized with heart failure: the TRANSFORM-HF randomized clinical trial. JAMA. 2023;329(3):214–223. DOI 10.1001/jama.2022.23924 PubMed 36648467
  6. Felker GM, Lee KL, Bull DA, et al. Diuretic strategies in patients with acute decompensated heart failure (DOSE). N Engl J Med. 2011;364(9):797–805. DOI 10.1056/NEJMoa1005419 PubMed 21366472
  7. Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA guideline for the management of heart failure. Circulation. 2022;145(18):e895–e1032. Later adaptation DOI 10.1161/CIR.0000000000001063 PubMed 35363499
  8. Mullens W, Damman K, Harjola V-P, et al. The use of diuretics in heart failure with congestion: a position statement from the Heart Failure Association of the European Society of Cardiology. Eur J Heart Fail. 2019;21(2):137–155. Later adaptation DOI 10.1002/ejhf.1369 PubMed 30600580

Formula version: Loop diuretic equivalence (Brater 1998 · Felker 2020) · MediHelp calc v1.3.1

Formula and sources checked on 2026-11-02

When this estimate is not valid

5
  • A starting estimate of equal diuretic effect, not a prescription. Response is judged by urine output, weight and symptoms within hours, and the dose is adjusted; in heart failure a dose that gives no response is usually doubled rather than increased by small steps (threshold drug).
  • Not for choosing a dose in acute decompensated heart failure: there the IV dose is set from the home dose (the DOSE trial used 1 to 2.5 times the home oral dose given IV) and from the diuretic response, not from a conversion.
  • Heart failure (gut oedema, reduced absorption and delivery) and chronic kidney disease (reduced tubular delivery, higher ceiling dose) both shift the dose-response curve; the same ratio does not mean the same effect in every patient.
  • The drugs differ in half-life and duration: torsemide (about 3 to 4 h, acts 6 to 12 h) is usually given once daily, furosemide and bumetanide twice daily for the same total effect. TRANSFORM-HF (2023) found no mortality difference between torsemide and furosemide.
  • Ratios are from pharmacology reviews (Brater 1998; Felker 2020) and product labels, not from a randomised equivalence trial. Some references quote bumetanide 1 mg ≈ furosemide 40 mg IV; the dose is always titrated to response.

Estimate only. Interpret it with the patient's clinical picture and the product label.

About this calculator

What it is
Converts a dose of one loop diuretic, oral or IV, into the approximately equivalent dose of another (furosemide, torsemide, bumetanide, ethacrynic acid).
Why it is used
Patients switch between oral and IV furosemide on admission and discharge, and between agents when absorption or response is poor; the ratios are easy to misremember (furosemide 40 mg oral ≈ 20 mg IV ≈ torsemide 20 mg ≈ bumetanide 1 mg).
How to use it
Each dose is turned into "units" of 40 mg oral furosemide using published potency and bioavailability tables, then into the target drug and route.
How to read the result
The result is a starting estimate: the dose is then titrated to urine output and weight. Oral furosemide absorption is unpredictable, kidney disease needs larger doses, and acute decompensation is dosed from the home dose and the response, not from a conversion.

How it is calculated

Dose of drug B = dose of drug A ÷ equivalent mg of A × equivalent mg of B

Each dose is turned into units of 40 mg oral furosemide using published potency and bioavailability tables (Brater 1998; Felker 2020), then into the target drug and route.

equivalent mg (1 unit = 40 mg oral furosemide): furosemide oral 40, IV 20; torsemide oral 20, IV 20; bumetanide oral 1, IV 1; ethacrynic acid oral 50, IV 50

The equivalent mg of one unit are furosemide oral 40 and IV 20, torsemide oral 20 and IV 20, bumetanide oral 1 and IV 1, and ethacrynic acid oral 50 and IV 50. Furosemide is absorbed about half as well by mouth as by vein; torsemide and bumetanide are close to 1:1.

Enter one dose, not the daily total. The calculator also shows the amount of oral furosemide that is approximately equivalent, and the equivalent of every other drug and route in the table.

Notes appear when oral furosemide is involved (its absorption varies widely), at 160 mg or more of oral furosemide equivalent, above a labelled maximum, for ethacrynic acid, and when eGFR is below 30 mL/min/1.73 m² or the patient is on dialysis.

Limits: a dose from 0.1 to 1000 mg. The calculator shows each step of the arithmetic.

Worked example

40 mg of IV furosemide converted to oral torsemide:

  1. 40 ÷ 20 × 20 = 40 mg
  2. 40 ÷ 20 = 2

40 mg of IV furosemide is approximately equivalent to 40 mg of oral torsemide (a starting estimate). That is 2 units of 40 mg oral furosemide, so about 80 mg of oral furosemide; the same effect is approximately bumetanide 2 mg or ethacrynic acid 100 mg by mouth.

Questions

Is the result a dose to give?

No. It is a starting estimate of equal diuretic effect. Response is judged by urine output, weight and symptoms, and the dose is adjusted.

Why does oral furosemide carry a warning?

Oral furosemide absorption ranges from about 10% to 100% between people and from day to day, and falls further with gut oedema, so the 2:1 oral-to-IV ratio is only an average.

Can it be used for acute decompensated heart failure?

Not as a conversion. In acute decompensated heart failure the IV dose is set from the home dose and the diuretic response (the DOSE trial used 1 to 2.5 times the home oral dose given IV).

Does kidney function change the ratio?

The equivalence ratio is unchanged, but with an eGFR under 30 mL/min/1.73 m² much larger doses are needed for the same effect, so the starting dose is usually larger and is titrated to urine output.

Why is ethacrynic acid in the list?

It is used when a sulfonamide allergy limits the other loop diuretics. Its 50 mg ≈ 40 mg furosemide equivalence is approximate, and it is the most ototoxic of the group.

Use the calculators in the MediHelp app

Estimate only. Interpret it with the patient's clinical picture and the product label.