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Dosage Calcs

Methodology

How Dosage Calcs builds, checks, and tests its calculators.

Formulas are checked against published references

Each formula is compared against open nursing textbooks (OpenStax) and NCBI StatPearls articles before it is built. The Dosage Calculator uses Desired ÷ Have × Quantity, as described in OpenStax Pharmacology for Nurses and NCBI StatPearls. See all sources.

One calculation engine

Every answer comes from a single calculation engine that is separate from the page design. The calculators, Med-Math Practice answers, Learning Center worked examples and the Quick Reference all use this same engine, so they can’t disagree. Dimensional analysis and ratio-and-proportion views explain the same result in different ways; they don’t calculate it again separately. Weight conversions use 1 kg = 2.2 lb everywhere.

Units are checked and conversions are exact

  • Only supported units are accepted. Unsupported or mismatched units are rejected, not guessed.
  • The ordered and available doses are converted to a common unit before dividing, using 1 g = 1,000 mg and 1 mg = 1,000 mcg.
  • Every conversion is shown in the worked solution.
  • The answer always carries the unit of the quantity (tablet, capsule, or mL).

Exact arithmetic

Entered numbers are stored as exact fractions rather than floating-point approximations, so results such as 9.9999999997 mL cannot happen. Nothing is rounded mid-calculation.

Safe number display

Results always use a leading zero (0.5, not .5) and never add trailing zeros (5, not 5.0). Milliliters are written mL and micrograms mcg.

Rounding is calculator-specific

There is no one-size-fits-all rounding rule. The Dosage Calculator shows the exact mathematical result. When a result never ends (such as one-third), it is shown as an approximate mathematical result marked ≈. The 4 decimal places shown are a display choice, not a clinical rounding rule. Calculators with established conventions, such as IV drip rates in whole drops per minute, state their own rule on the page.

Known-answer and edge-case testing

Each calculator has automated tests with hand-verified answers. They cover unit conversions, decimal results, leading and trailing zeros, zero and negative values, blank and malformed input, very small and very large numbers, and repeated calculations. The tests must pass before changes are released.

Practice problems and worked examples

Med-Math Practice builds problems from templates with fictional values, and every answer key comes from the same calculation engine. Automated checks generate and validate 24,000 problems. Learning Center worked examples are also produced by the engine and compared with hand-checked answers.

NCLEX-RN Review and Nursing Notes

These sections are original written content based on the public sources listed on each page and on the Sources page. Automated checks confirm their structure (for example, that every question has an answer key and rationale, and that example notes only use facts given in their scenario). Automated testing does not equal clinical review: it cannot confirm that clinical content is accurate or current.

What the calculators do not do

Dosage Calcs performs mathematical calculations on values you provide. It does not prescribe or decide on medication therapy. It does not decide whether a medication, order, or dose is appropriate, and it has no drug database. Educational use.

Review status

Dosage Calcs has not yet been reviewed by an independent clinician. All NCLEX-RN Review and Nursing Notes content is in Draft status pending licensed professional review. If that changes, this page will name the reviewer and their qualifications.