Dosage calculator by weight

Calculate the correct dosage of medication based on body weight. Safe and accurate.

Accurate
Calculation by body weight
Safe
Excess warnings
Multilingual
4 languages

Important Tips

Always consult your doctor before taking medications.

Make sure the information you enter is accurate.

For children, use special children's dosages.

About the dosage calculator

Our calculator will help you calculate the correct dosage of medication based on body weight. This is especially important for accurate dosing of drugs.

Correct dosage of medications is critical to treatment effectiveness and patient safety. Calculating the dose by weight allows you to personalize treatment and avoid both insufficient effectiveness and overdose. The calculator takes into account body weight and the recommended dosage per kilogram, calculating both a single and daily dose, taking into account the frequency of administration.

Examples of calculating drug dosage by weight

Let's look at practical examples of calculating dosage for different cases:

Example 1: Adult, antibiotic

Calculation of antibiotic dosage for an adult

Входные данные:

Body weight: 70 kg Dosage: 20 mg/kg Frequency of administration: 2 times a day

Расчёт:

Dose per kg: 20 mg/kg Single dose = 70 kg × 20 mg/kg = 1400 mg Daily dose = 1400 mg × 2 = 2800 mg

Результат:

Single dose: 1400 mg

Дозировка:

Daily dose: 2800 mg (2 times a day)

Example 2: Child, antipyretic

Calculation of paracetamol dosage for a child

Входные данные:

Body weight: 25 kg Dosage: 15 mg/kg Frequency of administration: 3 times a day Maximum daily dose: 60 mg/kg

Расчёт:

Single dose = 25 kg × 15 mg/kg = 375 mg Daily dose = 375 mg × 3 = 1125 mg Maximum for 25 kg = 25 × 60 = 1500 mg 1125 < 1500 – safe

Результат:

Single dose: 375 mg

Дозировка:

Daily dose: 1125 mg (within normal limits)

Example 3: Exceeding the maximum dose

The case where the calculated dose exceeds the maximum

Входные данные:

Body weight: 90 kg Dosage: 25 mg/kg Frequency of administration: 3 times a day Maximum daily dose: 2000 mg

Расчёт:

Single dose = 90 × 25 = 2250 mg Daily dose = 2250 × 3 = 6750 mg Maximum: 2000 mg 6750 > 2000 - EXCESS!

Результат:

Single dose: 2250 mg

Дозировка:

⚠️ The maximum dose has been exceeded! Doctor's consultation required

Example 4: Light Adult

Calculation for a person with low body weight

Входные данные:

Body weight: 50 kg Dosage: 10 mg/kg Frequency of administration: 1 time per day

Расчёт:

Single dose = 50 × 10 = 500 mg Daily dose = 500 × 1 = 500 mg

Результат:

Single dose: 500 mg

Дозировка:

Daily dose: 500 mg (1 time per day)

Example 5: Large person, high frequency of use

Calculation for a person with a large body weight

Входные данные:

Body weight: 100 kg Dosage: 12 mg/kg Frequency of administration: 4 times a day

Расчёт:

Single dose = 100 × 12 = 1200 mg Daily dose = 1200 × 4 = 4800 mg

Результат:

Single dose: 1200 mg

Дозировка:

Daily dose: 4800 mg (4 times a day)

Example 6: Teenager, medium dosage

Calculation for a teenager

Входные данные:

Body weight: 60 kg Dosage: 18 mg/kg Frequency of administration: 2 times a day Maximum daily dose: 2400 mg

Расчёт:

Single dose = 60 × 18 = 1080 mg Daily dose = 1080 × 2 = 2160 mg Maximum: 2400 mg 2160 < 2400 - safe

Результат:

Single dose: 1080 mg

Дозировка:

Daily dose: 2160 mg (safe, below maximum)

How dosage is calculated

Dosage is calculated using the formula: Body weight × Dosage per kg × Number of doses per day. The result shows the dose per dose and the total daily dose.

Safety

Always consult your doctor before taking any medications. The calculator is for informational purposes only and does not replace medical advice.

Advantages

Accurate calculation, support for different units of measurement, warnings about exceeding doses, multilingual interface.

Frequently Asked Questions

How is dosage calculated by weight?

Dosage is calculated by multiplying body weight (in kg) by dosage per kilogram of weight (mg/kg), then multiplying the result by the number of doses per day. Formula: Single dose = Body weight × Dosage per kg; Daily dose = Single dose × Number of doses.

Can it be used for children?

Yes, the calculator can be used by children, but with caution. For children, it is especially important to use special children's dosages indicated in the instructions for the drug, and be sure to consult with a pediatrician. Children's bodies are more sensitive to medications, and the wrong dosage can be dangerous.

What to do if the dose is exceeded?

If the calculated dose exceeds the maximum daily dose indicated in the calculator, do not take the medicine under any circumstances without consulting a doctor. Be sure to consult a specialist to adjust your treatment regimen. Exceeding the maximum dose is dangerous to health.

How accurate are the calculator's calculations?

The calculator performs accurate mathematical calculations based on the entered data. However, the result depends on the accuracy of the entered data (body weight, dosage per kg). The calculator does not take into account individual characteristics of the body, liver disease, kidney disease and other factors. Always consult your doctor.

Can I use a calculator instead of consulting a doctor?

No! The calculator is for informational purposes only and does not replace medical advice. Only a doctor can take into account all factors (health status, other medications, contraindications) and prescribe the correct dosage. Self-medication is dangerous to health.

How to correctly measure body weight for calculation?

Body weight should be measured on an accurate scale, without clothing or in minimal light clothing, in the morning on an empty stomach. Weigh yourself at the same time of day for accuracy. For an accurate calculation, use the current weight, not the old one.

What is the difference between a single and daily dose?

A single dose is the amount of medicine to take at one time. The daily dose is the total amount of medicine that needs to be taken for the whole day (the sum of all single doses). For example, if a single dose is 500 mg and taken 3 times a day, then the daily dose = 500 × 3 = 1500 mg.

What is the dosage per kilogram?

Dosage per kilogram (mg/kg) is the number of milligrams of medication needed per kilogram of body weight. For example, a dosage of 20 mg/kg means that for every kilogram of weight you need 20 mg of the drug. For a 70 kg person this would be 70 x 20 = 1400 mg.

How to convert pounds to kilograms?

1 lb = 0.453592 kg (approximately 0.454 kg). To translate: Weight in kg = Weight in pounds × 0.454. For example, 150 pounds = 150 × 0.454 = 68.1 kg. The calculator has a function for switching units of measurement.

Can it be used for older people?

Yes, you can use it, but with special attention. Older adults often have decreased kidney and liver function, which affects drug elimination. Dosages may require adjustment. Be sure to consult a doctor who will take into account your age and health status.

What if I missed a medication dose?

If one dose is missed, do not usually take a double dose to make up for the missed dose. Continue taking as usual. If you have missed many doses or are unsure, consult your doctor. Do not increase the dose on your own.

How often can I use the calculator?

The calculator can be used as often as needed to check the dosages of different medications. However, remember that the dosage should be prescribed by a doctor and the calculator is for checking and understanding only. Do not change the dosage yourself based on calculations.

Does the calculator take into account interactions with other medications?

No, the calculator does not take into account interactions with other medications you take. Interactions may affect the effectiveness and safety of dosage. Only a doctor can take into account all the medications you are taking and prescribe a safe dosage.

Can it be used for pregnant and lactating women?

For pregnant and breastfeeding women, dosages are often different and require special attention. Many medications are contraindicated during pregnancy and lactation. Be sure to consult with your doctor, who will take these factors into account and prescribe a safe dosage or alternative treatment.

What to do if the dosage per kg is not indicated in the instructions?

If the dosage per kg is not indicated, then the drug has a fixed dosage that does not depend on weight. In this case, the calculator is not suitable. Use the dosage indicated in the instructions or prescribed by your doctor. Not all medications are dosed by weight.

How is kidney function taken into account in the calculation?

The calculator does not take into account kidney function. In case of kidney disease, the dosage of many medications must be reduced, since they are eliminated by the kidneys more slowly. If you have kidney problems, be sure to consult your doctor to adjust the dosage.

How is liver function taken into account in the calculation?

The calculator does not take liver function into account. In case of liver diseases, the metabolism of drugs is impaired, and dosages require adjustment. For liver diseases, the doctor should adjust the dosage taking into account the condition of the liver.

Can it be used on animals?

The calculator is designed for people. For animals, dosages may vary significantly. Do not use a calculator to calculate dosages for animals - contact a veterinarian who knows the specifics of dosing drugs for animals.

What is the maximum daily dose?

The maximum daily dose is the maximum allowable amount of medication that can be taken per day without risk to health. Exceeding this dose is dangerous and can lead to overdose and side effects. The calculator warns if the maximum dose is exceeded.

How to take age into account when calculating dosage?

The calculator takes into account body weight, but not age directly. However, in children and older adults, body weight often correlates with age, and weight calculations indirectly account for these differences. For exact dosage, age must be taken into account by the doctor separately.

Can I split the tablet if the calculated dose is less?

Not all tablets can be divided - it depends on the form of release. Coated tablets, capsules, and modified-release tablets usually cannot be split. If you need a lower dose, ask your doctor or pharmacist to see if there is a drug with the right dosage or a dosage form for dividing.

How to recalculate the dosage when changing weight?

If the weight changes, the dosage must be recalculated: enter the new weight into the calculator with the same dosage parameters. If you lose or gain weight, especially during long-term treatment, consult your doctor to recalculate your dosage based on your new weight.

Does the calculator take into account individual tolerance?

No, the calculator does not take into account individual tolerance to the drug, allergic reactions, concomitant diseases, or genetic characteristics of metabolism. Only a doctor can take all these factors into account and prescribe a safe and effective dosage.

Can the calculator be used for all types of medications?

The calculator is only suitable for drugs dosed by body weight (mg/kg). Many medications have a fixed dosage that is not weight dependent. Also, some drugs require special calculation methods (for example, chemotherapy). Use the calculator only for drugs with dosage per kg.

How does the reception frequency affect the calculation?

Dosing frequency determines how many times a day you need to take the medicine. It affects the daily dose: the more often you take it, the higher the daily dose. For example, with a single dose of 500 mg: 1 time per day = 500 mg/day, 2 times = 1000 mg/day, 3 times = 1500 mg/day.

What to do if the calculated dose does not correspond to the available release form?

If the calculated dose does not match the available dosage forms (for example, you need 375 mg, but the tablets are only 250 or 500 mg), do not try to adjust the dosage yourself. Contact your doctor - he will select the appropriate form or adjust the dosage regimen.

Can the calculator be used for prophylactic doses?

Yes, the calculator can be used to calculate prophylactic doses if they are indicated in mg/kg. However, preventive doses often differ from therapeutic ones and should be prescribed by a doctor, taking into account individual risk factors and health status.

How to account for digestive disorders?

The calculator does not take into account digestive disorders that may affect the absorption of medications. If there are problems with the gastrointestinal tract (ulcers, inflammation, surgery), absorption may be impaired and the dosage requires adjustment. Discuss this with your doctor.

Can I use the calculator for IV drugs?

The calculator can calculate the dosage, but intravenous medications require special care and professional administration. Never administer intravenous medications yourself. Injections must be performed by medical personnel, even if you know the dosage.

What if the instructions contradict the calculation?

Always follow the instructions for the drug and the doctor's prescription. If the calculator's calculations contradict the instructions or doctor's prescription, use official data. The calculator is an auxiliary tool and does not replace medical advice.