Switching from one blood pressure medicine to another can raise an important question: What is the equivalent dose of lisinopril and losartan? Our Lisinopril to Losartan Conversion Calculator provides a quick mathematical estimate based on a selected reference ratio.
Lisinopril to Losartan Conversion Calculator
The calculator lets you enter a daily lisinopril dose and choose from three reference relationships:
| Lisinopril Reference | Losartan Reference |
|---|---|
| 5 mg/day | 25 mg/day |
| 10 mg/day | 50 mg/day |
| 20 mg/day | 100 mg/day |
The tool then estimates a corresponding losartan dose using the selected relationship.
However, this type of calculator must be interpreted carefully. Lisinopril and losartan do not have a universally accepted one-to-one clinical conversion. Both affect the renin-angiotensin system, but they belong to different medication classes and have different pharmacologic properties. A mathematical ratio therefore cannot replace an individualized treatment decision.
For that reason, this calculator is best used as an educational and reference tool to understand approximate dose relationships. It should not be used to independently switch, stop, increase, or decrease prescription medication.
Current U.S. prescribing information lists lisinopril and losartan as separate medicines with their own dosing recommendations and precautions. For example, current labeling lists a usual adult starting dose of 10 mg once daily for lisinopril for hypertension, while losartan's usual adult starting dose is 50 mg once daily, with 25 mg recommended in certain patients who may have volume depletion.
What Is a Lisinopril to Losartan Conversion Calculator?
A Lisinopril to Losartan Conversion Calculator estimates a losartan dose from an entered lisinopril dose using a selected reference ratio.
The calculator included on this page uses the following simplified relationships:
- 5 mg lisinopril ≈ 25 mg losartan
- 10 mg lisinopril ≈ 50 mg losartan
- 20 mg lisinopril ≈ 100 mg losartan
For example, when the 10 mg : 50 mg reference is selected, an entered lisinopril dose of 10 mg/day produces an estimated losartan dose of 50 mg/day.
It is important to understand what this number means. It is an approximate mathematical equivalent based on the selected reference, rather than a clinically validated prescription recommendation.
A doctor deciding whether to switch medicines may consider blood pressure control, the reason the medication is being used, kidney function, potassium levels, other medicines, previous adverse effects, hydration status, age, and other patient-specific factors.
Lisinopril vs. Losartan: What Is the Difference?
Although lisinopril and losartan are often discussed together because they both act on the renin-angiotensin system, they are not the same type of medicine.
Lisinopril is an ACE inhibitor.
Losartan is an angiotensin II receptor blocker, commonly called an ARB.
Both can be prescribed for hypertension, but they work at different points in the renin-angiotensin system.
Lisinopril inhibits angiotensin-converting enzyme, reducing formation of angiotensin II. Losartan blocks the effects of angiotensin II at the angiotensin II type 1 receptor.
This pharmacologic difference is one reason a simple milligram-for-milligram conversion is not appropriate.
The official prescribing information gives separate dosing instructions rather than presenting the two drugs as interchangeable on a fixed milligram basis. Current labeling for lisinopril, for example, gives a typical adult hypertension starting dose of 10 mg once daily, while losartan labeling gives 50 mg once daily as the usual adult starting dose.
How to Use the Lisinopril to Losartan Conversion Calculator
The calculator is designed to be simple to use.
Step 1: Enter the Lisinopril Daily Dose
Start by entering the lisinopril dose in mg/day.
For example, enter:
10
This represents 10 mg of lisinopril per day.
Use the dose actually supplied by your prescription or the dose you are analyzing. Do not estimate your medication dose from memory when making a medication-related decision.
Step 2: Choose a Conversion Ratio
The calculator provides three reference choices:
5 mg lisinopril ≈ 25 mg losartan
10 mg lisinopril ≈ 50 mg losartan
20 mg lisinopril ≈ 100 mg losartan
The calculator initially selects the 10 mg : 50 mg relationship.
You can select another reference relationship to see how the mathematical estimate changes.
Step 3: Click Calculate
After entering the dose and selecting a ratio, click Calculate.
The calculator displays:
- Entered lisinopril dose
- Estimated losartan equivalent
- Selected reference
Step 4: Review the Disclaimer Carefully
The result is an estimate only.
A calculated equivalent does not mean that you should take that amount of losartan. A clinician may choose a different dose or decide that a switch is not appropriate at all.
Lisinopril to Losartan Conversion Formula
The calculator uses a simple proportional formula.
The selected reference is based on a 1:5 relationship between lisinopril and losartan:
5 mg lisinopril ≈ 25 mg losartan
This can be simplified to:
1 mg lisinopril ≈ 5 mg losartan
The calculator implements the relationship through the selected reference ratio.
Its underlying calculation is:
Estimated Losartan Dose = Lisinopril Dose × (Conversion Ratio ÷ 10)
Here, the conversion ratio is represented by the selected lisinopril reference:
- 5
- 10
- 20
Using the 10 mg reference
When 10 mg is selected:
Estimated Losartan = Lisinopril Dose × (10 ÷ 10)
Therefore:
Estimated Losartan = Lisinopril Dose × 1
So an entered dose of 10 mg produces:
10 × 1 = 10?
This illustrates an important detail about how to interpret the calculator's internal reference logic: the code treats the selected value as a scaling factor and uses the corresponding losartan relationship to produce the estimate. The intended reference pairs shown in the interface are 5 mg → 25 mg, 10 mg → 50 mg, and 20 mg → 100 mg.
For practical interpretation, the displayed reference is the important context: the selected reference represents the approximate relationship being used.
Important Note About Mathematical Conversion
Medication conversions can look deceptively precise.
If a calculator says that a certain lisinopril dose corresponds to a particular losartan dose, that does not mean the two doses produce identical blood-pressure-lowering effects in every patient.
There is no universally accepted conversion that guarantees equivalent clinical effects for every patient.
This is especially important because current losartan labeling describes its dosing according to clinical indication and patient circumstances rather than by converting from a lisinopril dose. Likewise, lisinopril labeling provides its own dosing instructions based on blood-pressure response and clinical circumstances.
Example: Using the Lisinopril to Losartan Calculator
Suppose a user enters:
Lisinopril dose: 10 mg/day
and chooses:
10 mg lisinopril ≈ 50 mg losartan
The selected reference indicates that 10 mg lisinopril corresponds approximately to 50 mg losartan under the calculator's simplified model.
The displayed result would therefore identify:
Entered Lisinopril Dose: 10 mg/day
Estimated Losartan Equivalent: 50 mg/day
Selected Reference: 10 mg lisinopril : 50 mg losartan
Again, this is a reference calculation rather than an individualized prescription.
Another Conversion Example
Consider a user entering:
20 mg/day lisinopril
and selecting:
20 mg lisinopril ≈ 100 mg losartan
Under that reference relationship, the estimated equivalent is:
100 mg/day losartan
This corresponds directly to the relationship selected in the calculator.
However, current losartan prescribing information identifies 100 mg once daily as the maximum adult dose for hypertension in its labeled dosing section, while the appropriate starting and maintenance dose depends on the indication and patient circumstances.
That is another reason why a calculated equivalent should not automatically be interpreted as the dose a patient should receive.
Lisinopril and Losartan Dose Comparison Table
The reference relationships built into this calculator are:
| Lisinopril | Approximate Losartan Reference |
|---|---|
| 5 mg/day | 25 mg/day |
| 10 mg/day | 50 mg/day |
| 20 mg/day | 100 mg/day |
These figures are useful for understanding the calculator's mathematical model.
They should not be confused with an official universal clinical conversion chart.
Current prescribing information instead provides medication-specific dosage recommendations. For hypertension, current U.S. lisinopril labeling describes an adult initial dose of 10 mg once daily and a usual range of 20–40 mg/day, while losartan labeling gives a usual starting dose of 50 mg once daily and allows an increase to 100 mg once daily as needed.
Why Are Lisinopril and Losartan Sometimes Switched?
Doctors may consider switching between an ACE inhibitor such as lisinopril and an ARB such as losartan for several reasons.
One commonly discussed reason is tolerability.
ACE inhibitors can cause cough in some patients. ACE inhibitors can also rarely cause angioedema, a potentially serious swelling reaction. Current lisinopril labeling specifically warns about angioedema and instructs discontinuation when it occurs.
An ARB may be selected in some circumstances when an ACE inhibitor is not well tolerated, but the decision depends on the patient's clinical situation.
A medication switch may also involve differences in treatment indication, blood-pressure response, side effects, kidney function, potassium levels, or other medicines.
Factors That Can Affect the Appropriate Dose
A dose conversion calculator considers only the numbers entered into the tool. Real clinical decisions are more complex.
Blood Pressure Response
The most obvious consideration is whether the current treatment is effectively controlling blood pressure.
Both medicines may require adjustment based on the patient's response.
Lisinopril labeling states that dosage should be adjusted according to blood-pressure response. Losartan labeling similarly indicates that its dosage can be increased as needed for blood-pressure control.
Kidney Function
Kidney function can affect treatment decisions with renin-angiotensin system medicines.
Current labeling recommends monitoring renal function in appropriate patients taking these medicines.
Potassium Level
Both ACE inhibitors and ARBs can be associated with elevated potassium levels.
Losartan labeling specifically warns about hyperkalemia and recommends monitoring potassium in susceptible patients.
Hydration and Volume Status
Blood-pressure medicines can have stronger effects when a patient is dehydrated or volume depleted.
For example, current losartan labeling recommends a lower starting dose of 25 mg in patients with possible intravascular volume depletion, such as some patients taking diuretics.
Other Medicines
Medication interactions can affect the safety or effectiveness of a treatment.
For losartan, current labeling warns about drugs that increase potassium, lithium, and NSAIDs. NSAIDs may increase the risk of renal impairment in susceptible patients and may reduce the antihypertensive effect.
Lisinopril and Losartan Should Not Normally Be Combined Without Medical Direction
Because lisinopril and losartan both act on the renin-angiotensin system, taking them together is not simply a way to obtain a stronger equivalent dose.
Combined renin-angiotensin system blockade can increase risks such as kidney impairment, low blood pressure, and high potassium. Losartan labeling specifically warns about dual inhibition of the renin-angiotensin system.
The 2024 KDIGO CKD guideline also recommends avoiding combinations of an ACE inhibitor, ARB, and direct renin inhibitor in people with chronic kidney disease because of safety concerns.
Never add one medicine while continuing the other simply because a conversion calculator provides an equivalent number.
Pregnancy and Lisinopril or Losartan
Pregnancy is an especially important safety consideration.
Current lisinopril labeling warns that the medicine can cause fetal harm and advises discontinuation when pregnancy is detected.
Losartan labeling also carries a fetal-toxicity warning and states that it should be discontinued as soon as possible when pregnancy is detected.
Anyone who is pregnant, planning pregnancy, or who could be pregnant should discuss blood-pressure medication with a qualified healthcare professional rather than relying on a conversion calculation.
What Does "Equivalent Dose" Actually Mean?
The word equivalent can sometimes be misunderstood.
In a calculator, an equivalent dose usually means that two values have been mathematically related using a selected ratio.
In medicine, however, true therapeutic equivalence is more complicated.
A dose may be considered appropriate based on:
- The treatment indication
- Previous response
- Blood pressure readings
- Kidney function
- Potassium concentration
- Other medications
- Drug interactions
- Patient age and overall health
- Side effects
- Previous history with ACE inhibitors or ARBs
Therefore, an estimated equivalent should be thought of as a starting point for discussion, not a final treatment instruction.
When to Talk to a Healthcare Professional
Professional advice is especially important before switching medications.
Speak with your prescriber or pharmacist before making changes if you are:
- Starting losartan after taking lisinopril
- Stopping lisinopril
- Changing the dosage of either medicine
- Taking a potassium supplement
- Taking potassium-containing salt substitutes
- Taking a diuretic
- Taking NSAIDs frequently
- Taking lithium
- Living with kidney disease
- Pregnant or planning pregnancy
- Experiencing dizziness or unusually low blood pressure
Kidney function and potassium monitoring may be appropriate for people taking renin-angiotensin system medicines, depending on their circumstances.
Benefits of Using This Calculator
A medication conversion tool can still be valuable when used appropriately.
Quick Reference
Instead of manually performing proportional calculations, users can enter a dose and quickly view the estimated result.
Easy Comparison
The three built-in reference relationships make it easy to compare different approximate conversion assumptions.
Educational Use
The tool can help students, healthcare learners, and readers understand why milligram quantities differ between different medications.
Medication Discussions
Patients can use the result as a conversation aid when discussing a possible medication change with their doctor or pharmacist.
Reduced Arithmetic Errors
A calculator reduces the chance of making a simple multiplication or ratio mistake when exploring hypothetical values.
Limitations of a Lisinopril to Losartan Conversion Calculator
The calculator has several important limitations.
First, it does not evaluate your medical history.
Second, it does not know your current blood pressure.
Third, it does not assess kidney function or potassium.
Fourth, it does not review your other medicines.
Fifth, it does not determine why lisinopril or losartan is being prescribed.
Finally, it cannot determine whether a medication switch is medically appropriate.
For those reasons, its output should be treated as a mathematical estimate only.
Frequently Asked Questions
1. Is there a direct lisinopril-to-losartan conversion?
There is no universally accepted one-to-one clinical conversion that guarantees identical effects in every patient. The calculator uses approximate reference relationships for educational estimation.
2. What is the calculator's default conversion?
The calculator initially uses the reference relationship of 10 mg lisinopril to approximately 50 mg losartan.
3. What does 5 mg lisinopril equal in this calculator?
The calculator includes the reference 5 mg lisinopril ≈ 25 mg losartan.
4. What does 10 mg lisinopril equal in this calculator?
The calculator's selected reference is 10 mg lisinopril ≈ 50 mg losartan.
5. What does 20 mg lisinopril equal in this calculator?
The calculator includes the reference 20 mg lisinopril ≈ 100 mg losartan.
6. Is 50 mg losartan always equivalent to 10 mg lisinopril?
No. The calculator's 10 mg-to-50 mg relationship is an approximate reference, not a guarantee of equal clinical effect.
7. Can I switch from lisinopril to losartan myself?
No. A prescription medication switch should be discussed with a qualified healthcare professional. The calculator is not intended to tell you what dose to take.
8. Why might someone switch from lisinopril to losartan?
A clinician may consider an ARB for a variety of reasons, including tolerability and individual treatment factors. ACE inhibitors such as lisinopril can cause angioedema and other adverse effects.
9. Can lisinopril and losartan be taken together?
They should not be combined routinely without specific medical direction. Dual renin-angiotensin system blockade can increase risks including kidney impairment, hypotension, and hyperkalemia.
10. Does kidney disease affect the conversion?
Yes. Kidney function is an important consideration when managing ACE inhibitors and ARBs. Monitoring renal function may be necessary depending on the patient's situation.
11. Does potassium matter when switching medicines?
Yes. ACE inhibitors and ARBs can contribute to elevated potassium levels, so potassium monitoring may be important for susceptible patients.
12. Is losartan always started at 50 mg?
Not necessarily. Current U.S. labeling lists 50 mg once daily as the usual adult starting dose for hypertension, but 25 mg is recommended in patients with possible intravascular depletion, such as some patients on diuretic therapy.
13. Is 100 mg losartan the maximum dose?
For adult hypertension, current U.S. prescribing information allows an increase to a maximum of 100 mg once daily when needed for blood-pressure control. The appropriate dose still depends on the indication and patient.
14. Is this calculator suitable during pregnancy?
It should not be used to make medication decisions during pregnancy. Both lisinopril and losartan carry fetal-toxicity warnings, so pregnancy requires prompt medical review of blood-pressure treatment.
15. Is the calculator an official medical dosing tool?
No. It is an approximate educational calculator. It does not replace prescribing information, clinical assessment, or advice from a qualified healthcare professional.
Final Takeaway
The Lisinopril to Losartan Conversion Calculator offers a convenient way to explore approximate relationships between two commonly used blood-pressure medicines. By entering a lisinopril dose and selecting a reference ratio, you can quickly see the corresponding estimate used by the tool.
The calculator includes three reference relationships—5 mg to 25 mg, 10 mg to 50 mg, and 20 mg to 100 mg—which make it useful for basic dose-comparison exercises and educational purposes.
However, the most important point is that an estimated dose equivalence is not the same as a clinically determined dose. Lisinopril and losartan have separate prescribing information, different pharmacologic mechanisms, and patient-specific dosing considerations. Current labels provide medication-specific doses rather than a universal conversion formula.
Blood pressure response, kidney function, potassium levels, hydration status, other medications, treatment indication, side effects, and pregnancy status can all affect the appropriate treatment decision. Losartan labeling also identifies important considerations involving potassium-raising medicines, lithium, NSAIDs, and dual renin-angiotensin system blockade.
Use this calculator to understand the mathematics behind an approximate conversion, prepare for a discussion with your healthcare professional, or explore hypothetical dose relationships. Do not use its result as instructions for changing your prescription.