How Tablet & Oral Dosing Calculations Work
Tablet dose calculations convert a prescribed dose into the number of tablets required based on the tablet strength (mg per tablet).
Common real-world needs include converting weight-based orders (mg/kg) into total mg, applying maximum single-dose caps, and selecting practical tablet combinations when multiple strengths exist.
Common Tablet & Oral Dosing Calculations Explained
mg to tablets (milligrams to tablets)
Converts a prescribed dose (mg) into the number of tablets using tablet strength (mg/tablet). Used for quick tablet checks during medication prep.
Example question
The doctor prescribes 500 mg per dose. The tablets available are 250 mg per tablet. How many tablets should be given for one dose?
Worked example
Step 1
Dose = 500 mg
Step 2
Strength = 250 mg per tablet
Step 3
Tablets = 500 ÷ 250 = 2
Result: Answer: 2 tablets
💡 Dose ÷ strength = tablets.
mg/kg to tablets (weight-based tablet dosing)
First calculate the total mg dose from mg/kg × weight (kg). Then convert that total mg into tablets.
Example question
A child weighs 20 kg. The order is 10 mg/kg per dose. Tablets are 100 mg each. How many tablets are needed for one dose?
Worked example
Step 1
Total mg = 10 × 20 = 200 mg
Step 2
Tablets = 200 ÷ 100 = 2
Result: Answer: 2 tablets
💡 Calculate mg first, then convert to tablets.
Max dose cap & tablet combinations (multiple strengths)
Some orders include a maximum single-dose cap (do not exceed X mg). Calculate the weight-based dose first, apply the cap, then convert to tablets. If multiple tablet strengths exist, choose a practical combination that matches the target dose.
Example question
The order is 15 mg/kg for a patient who weighs 30 kg, but the maximum dose per administration is 400 mg. Tablets are 200 mg each. How many tablets should be given?
Worked example (cap applied)
Step 1
Calculated dose = 15 × 30 = 450 mg
Step 2
Apply cap = min(450, 400) = 400 mg
Step 3
Tablets = 400 ÷ 200 = 2
Result: Answer: 2 tablets (cap applied)
Worked example (multiple strengths)
Step 1
Start with 250 mg
Step 2
Remaining = 375 − 250 = 125 mg
Step 3
Add 125 mg tablet
Result: Answer: 1 × 250 mg + 1 × 125 mg
💡 Cap first, then plan tablets.
When These Calculators Are Used
- •Converting an ordered mg dose into tablets using tablet strength (mg/tablet)
- •Converting weight-based doses (mg/kg) into tablets
- •Applying maximum single-dose caps before finalising tablet counts
- •Selecting practical tablet combinations when multiple strengths exist
- •Estimating tablets per day based on how often the dose is taken
Clinical safety note: Do not assume tablets can be split. Some formulations must not be divided (e.g., modified-release or enteric-coated). Always confirm the medication order and local protocols. These calculators support calculation checking but do not replace professional judgement. Examples on this page are for calculation practice only.