Morphine ER
- SIG / Daily Dose
- 15 mg twice daily = 30 mg/day
- Factor
- 1
- Daily MME
- 30
- Running Total
- 30
Search This Guide
About PharmCalc
Built for the Way Pharmacy Actually Works.
What it is
PharmCalc is a free pharmacy workflow toolkit for common retail and specialty pharmacy math: day supply, refill timing, insulin, injections, eye and ear drops, inhalers, nasal sprays, topical medications, warfarin weekly dose, MME review, adherence, quantity to dispense, medication remaining, medication synchronization, and refrigerated shipment planning.
When to use it
Use PharmCalc when the math is repetitive, the assumptions need to be visible, or the workflow needs a fast second check before documentation, adjudication review, or pharmacist escalation.
Things to know
- PharmCalc supports arithmetic and workflow review. It does not make clinical decisions.
- Every result should be checked against the prescription, product, claim, payer rules, organizational policy, state requirements, and pharmacist guidance.
- Confidence should come from clear formulas, transparent assumptions, repeatable results, and consistent behavior—not mystery math.
Fast calculator access
Use the homepage for the calculator grid, search, favorites, settings, and Smart Fill.
Use the homepage for the calculator grid, search, favorites, settings, and Smart Fill.
Reference-first guide
Use this page when you need examples, formulas, assumptions, common mistakes, and calculation context.
Use this page when you need examples, formulas, assumptions, common mistakes, and calculation context.
Workflow support only
PharmCalc reduces repetitive math. It does not replace pharmacist review.
PharmCalc reduces repetitive math. It does not replace pharmacist review.
Quick Start
What it does
The main app gets you from a pharmacy question to the right calculator, reference, or workflow tool as quickly as possible.
When to use it
Use the calculator grid when you already know the tool you need. Use Search when you know the medication, concept, or workflow but not where it lives in PharmCalc.
Things to know
- Open PharmCalc.
- Use the calculator grid, Search, or Favorites to open the needed tool.
- Enter the relevant values: quantity, dose, frequency, dates, package size, or days supply.
- Select Calculate.
- Review the answer, warning notes, and math explanation.
- Copy the result when you need documentation support.
Calculate
Runs the selected module and displays the main result first.
Runs the selected module and displays the main result first.
Copy / Copy Note
Copies a documentation-style result when available.
Copies a documentation-style result when available.
Reset
Clears the current calculator. The standard calculator uses AC because it behaves like a normal calculator.
Clears the current calculator. The standard calculator uses AC because it behaves like a normal calculator.
History
Recent calculator results are kept so repeated workflow checks are easier to review.
Recent calculator results are kept so repeated workflow checks are easier to review.
Best practice:
Use PharmCalc to support the math, not to bypass the review. If an entry is vague, mismatched, future-dated, clinically unusual, or policy-dependent, stop and verify before relying on the result.
Use PharmCalc to support the math, not to bypass the review. If an entry is vague, mismatched, future-dated, clinically unusual, or policy-dependent, stop and verify before relying on the result.
Smart Fill Beta
What it does
Smart Fill analyzes prescription directions, identifies supported day-supply patterns, and opens the most relevant calculator when enough information is present.
See it in action
The demo below runs the real Smart Fill engine on three example SIGs — the routing, confidence, and prefilled fields are live output, not a recording.
When to use it
- Use it when a SIG is readable but annoying to translate into daily use.
- Use it for common oral, liquid, insulin, eye/ear drop, nasal spray, inhaler, PRN, taper, and patterned dosing directions.
- Use it as a starting point, then review the populated fields before calculating.
Things to know
- A good parser does not always return an answer. It knows when the SIG is not specific enough.
- Smart Fill refuses or warns on vague, unsafe, unsupported, or policy-dependent directions.
- Sliding-scale insulin can be detected, but daily units still require manual review unless a daily-unit estimate is provided.
- Topical directions still require policy-approved grams/day for day supply.
Examples
Oral:
“Take 1 tablet twice daily” → Standard Day Supply, 2 tablets/day.
“Take 1 tablet twice daily” → Standard Day Supply, 2 tablets/day.
PRN:
“Take 1–2 tablets every 6 hours as needed, max 8 tablets/day” → Standard Day Supply using the documented max daily amount.
“Take 1–2 tablets every 6 hours as needed, max 8 tablets/day” → Standard Day Supply using the documented max daily amount.
Liquid:
“Take 5 mL by mouth twice daily” → Oral liquid mode, 10 mL/day after the user enters mL dispensed.
“Take 5 mL by mouth twice daily” → Oral liquid mode, 10 mL/day after the user enters mL dispensed.
Insulin:
“Inject 40 units every morning and 20 units every evening” → Insulin, 60 units/day.
“Inject 40 units every morning and 20 units every evening” → Insulin, 60 units/day.
Eye drops:
“Instill 1 drop in both eyes twice daily” → Eye/Ear, 4 drops/day.
“Instill 1 drop in both eyes twice daily” → Eye/Ear, 4 drops/day.
Nasal spray:
“Use 2 sprays in each nostril daily” → Inhalers & Nasal Sprays, 4 sprays/day.
“Use 2 sprays in each nostril daily” → Inhalers & Nasal Sprays, 4 sprays/day.
MME workflow:
Use Smart Fill to help interpret directions or day-supply patterns, then open the MME Calculator separately and use Add to Stack when multiple opioids need one combined total daily MME.
Use Smart Fill to help interpret directions or day-supply patterns, then open the MME Calculator separately and use Add to Stack when multiple opioids need one combined total daily MME.
Open tool
Fill Date, RTS, and Next Fill Date
What it does
The Fill Timing calculator estimates when a prescription may be eligible based on a previous fill date, days supply, and refill threshold.
When to use it
Use it for refill-too-soon review, next fill date checks, early refill triage, and quick claim-history conversations.
Things to know
Allowed days used = days supply × threshold
Estimated next fill date = last fill date + allowed days used
Estimated next fill date = last fill date + allowed days used
- Thresholds vary by payer, plan, drug class, and workflow.
- Claim response and pharmacy policy remain the source of truth.
- Controlled medications may require stricter review and pharmacist involvement.
Common mistakes
- Using the written date instead of the last fill or sold date when claim history controls the calculation.
- Ignoring reversed claims, partial fills, transfers, or previous pharmacy fills.
- Assuming all plans use the same threshold.
Open tool
Standard Day Supply
What it does
The Standard Day Supply calculator estimates day supply for tablets, capsules, PRN directions, dose ranges, tapers, multi-step schedules, and patterned dosing.
When to use it
Use it for common oral directions, quantity checks, max daily dose review, and schedules such as daily, BID, TID, QID, every other day, weekly, or MWF.
Things to know
Day supply = quantity dispensed ÷ units used per day
- Use maximum possible daily use for PRN ranges unless approved documentation says otherwise.
- Add each step separately for tapers and multi-step directions.
- Patterned schedules may convert weekly use into an average daily use.
Examples
BID
1 tablet twice daily = 2 units/day.
1 tablet twice daily = 2 units/day.
QOD
1 tablet every other day = 0.5 units/day.
1 tablet every other day = 0.5 units/day.
MWF
1 tablet Monday, Wednesday, Friday = 3 tablets/week, about 0.43 tablets/day.
1 tablet Monday, Wednesday, Friday = 3 tablets/week, about 0.43 tablets/day.
Common mistakes
- Using the minimum dose in a range when the day supply should use maximum possible use.
- Missing weekly pattern directions.
- Letting “as directed” produce a false sense of precision.
Open tool
Liquid Medication Day Supply
What it does
The Liquid Medication calculator estimates day supply from total mL dispensed and total mL used per day.
When to use it
Use it for suspensions, solutions, syrups, and other oral liquids when directions include a measurable mL dose and frequency.
Things to know
mL per day = mL per dose × doses per day
Day supply = mL dispensed ÷ mL per day
Day supply = mL dispensed ÷ mL per day
- PRN ranges should usually use the maximum possible daily mL unless approved documentation says otherwise.
- Directions without a frequency need manual review.
- Quantity dispensed should match the billable/package quantity used in workflow.
Example
Example:
Dispense 300 mL. Take 5 mL twice daily. Daily use = 10 mL/day. Day supply = 300 ÷ 10 = 30 days.
Dispense 300 mL. Take 5 mL twice daily. Daily use = 10 mL/day. Day supply = 300 ÷ 10 = 30 days.
Open tool
Quantity to Dispense
What it does
Quantity to Dispense calculates how much medication is needed for a target day supply when the daily use is known.
When to use it
Use it when the prescription or workflow starts with the intended days supply and you need to confirm the quantity to dispense.
Things to know
Quantity to dispense = daily use × desired days supply
- This is the reverse of a standard day-supply calculation.
- Package size, plan limits, and pharmacy policy may still change what can be dispensed.
- Round only when the medication, package, and workflow allow it.
Example
Example:
2 tablets/day for 30 days requires 60 tablets.
2 tablets/day for 30 days requires 60 tablets.
Open tool
Insulin Day Supply
What it does
The Insulin calculator estimates day supply from total units available and total units used per day. It also works in reverse: select "Quantity needed from days supply" to size the dispense from units per day and a target days supply.
When to use it
Use it for vials, pens, fixed daily doses, split doses, and workflows where the patient has a clear daily-unit total.
Things to know
Total units = mL dispensed × concentration
Day supply = total units ÷ units used per day
Quantity needed = units used per day × target days supply, converted to packages
Day supply = total units ÷ units used per day
Quantity needed = units used per day × target days supply, converted to packages
- U-100 insulin contains 100 units/mL; U-200 contains 200 units/mL; U-300 contains 300 units/mL; U-500 contains 500 units/mL.
- Sliding-scale or correction-scale directions need a daily-unit estimate before day supply is reliable.
- Day supply is calculated on labeled units per day per standard payer convention; priming is not part of the dispensing math. Verify package size and day-supply policy.
- Reverse pen and box results round up to whole packages, because partial pens and boxes are not dispensed, and then state the day supply the rounded quantity actually covers.
- When rounding up exceeds the target, results also show the largest whole-package quantity that stays at or under the target days supply — useful when the target is a plan maximum. If even one package exceeds the target, the result says so explicitly.
- Reverse mL results return the exact volume needed; verify vial or package size before dispensing.
Example
Example:
One 3 mL U-100 pen contains 300 units. Five pens contain 1,500 units. At 50 units/day, day supply = 1,500 ÷ 50 = 30 days.
One 3 mL U-100 pen contains 300 units. Five pens contain 1,500 units. At 50 units/day, day supply = 1,500 ÷ 50 = 30 days.
Reverse example:
45 units/day for a 30-day supply needs 1,350 units. On 3 mL U-100 pens (300 units each) that is 4.5 pens exact, so 5 pens are dispensed — which actually covers 33.33 days.
45 units/day for a 30-day supply needs 1,350 units. On 3 mL U-100 pens (300 units each) that is 4.5 pens exact, so 5 pens are dispensed — which actually covers 33.33 days.
Open tool
Injection Day Supply
What it does
The Injection Day Supply calculator estimates day supply from the number of doses dispensed and the dosing frequency.
When to use it
Useful for weekly, every-2-week, every-28-day, and monthly injection workflows.
Things to know
Day supply = doses dispensed × days between doses
- Monthly schedules vary by calendar month. PharmCalc uses a standardized 30-day estimate when monthly frequency is selected.
- Injection day supply is a workflow estimate. Verify package size and directions.
- Some products have starter doses, titrations, or package-specific assumptions that need manual review.
Example
Example:
4 doses dispensed, used every 7 days = 28 days.
4 doses dispensed, used every 7 days = 28 days.
Open tool
Morphine Milligram Equivalent (MME) Calculator
What it does
The MME tool estimates daily morphine milligram equivalents for supported opioid medications and can stack multiple opioids into one total.
When to use it
Use it for workflow review, documentation support, and multi-opioid situations where total daily MME needs to be visible before pharmacist review.
Things to know
- MME values are workflow estimates and should be verified against policy and pharmacist guidance.
- Use MME Stack when more than one opioid is active.
- Methadone is excluded because its conversion is nonlinear and clinically complex.
Example
MME Stacking Example
| Medication | SIG / Daily Dose | Factor | Daily MME | Running Total |
|---|---|---|---|---|
| Morphine ER | 15 mg twice daily = 30 mg/day | 1 | 30 | 30 |
| Oxycodone | 10 mg every 6 hours PRN, max 4/day = 40 mg/day | 1.5 | 60 | 90 |
| Combined Total Daily MME | 90 | |||
Oxycodone
- SIG / Daily Dose
- 10 mg every 6 hours PRN, max 4/day = 40 mg/day
- Factor
- 1.5
- Daily MME
- 60
- Running Total
- 90
Combined Total Daily MME90
Open tool
Eye and Ear Drop Day Supply
What it does
The Eye and Ear Drop calculator estimates day supply from bottle size, drops per mL, drops per dose, affected eye or ear count, and frequency. It also works in reverse: select "Quantity needed from days supply" to calculate the mL required for a desired days supply.
When to use it
Use it for ophthalmic and otic directions where small changes in directions can dramatically change day supply.
Things to know
Total drops = mL dispensed × drops per mL
Day supply = total drops ÷ drops used per day
mL needed = drops used per day × desired days supply ÷ drops per mL
Day supply = total drops ÷ drops used per day
mL needed = drops used per day × desired days supply ÷ drops per mL
- Drops per mL is an assumption and may vary by product, bottle, and policy.
- Both eyes or both ears usually doubles daily use.
- Taper directions should be calculated step by step.
- Reverse results return the exact mL needed; match to the nearest available commercial bottle size before dispensing.
Example
Example:
5 mL at 20 drops/mL = 100 drops. 1 drop in both eyes twice daily = 4 drops/day. Day supply = 25 days.
5 mL at 20 drops/mL = 100 drops. 1 drop in both eyes twice daily = 4 drops/day. Day supply = 25 days.
Reverse example:
1 drop in both eyes twice daily = 4 drops/day. For a 25-day supply, 100 drops are needed. At 20 drops/mL, quantity needed = 100 ÷ 20 = 5 mL.
1 drop in both eyes twice daily = 4 drops/day. For a 25-day supply, 100 drops are needed. At 20 drops/mL, quantity needed = 100 ÷ 20 = 5 mL.
Open tool
Inhalers and Nasal Sprays
What it does
The Inhaler and Nasal Spray tools estimate day supply using actuations, sprays, puffs, devices dispensed, and daily use.
When to use it
Use these tools for single inhalers, multiple inhalers, nasal sprays, PRN max-use directions, and maintenance-and-reliever workflows.
Things to know
Day supply = total actuations or sprays ÷ daily use
- Package actuation counts matter. One canister, bottle, or device is not always one month.
- PRN directions need a max daily use if day supply is being calculated from maximum use.
- SMART therapy and maintenance-and-reliever directions may require separate maintenance and rescue assumptions.
Example
Example:
An inhaler with 120 actuations used 2 puffs twice daily uses 4 puffs/day. Day supply = 120 ÷ 4 = 30 days.
An inhaler with 120 actuations used 2 puffs twice daily uses 4 puffs/day. Day supply = 120 ÷ 4 = 30 days.
Open tool
Topical Cream and Ointment Day Supply
What it does
The Topical calculator estimates day supply when grams per day or policy-approved application assumptions are available.
When to use it
Use it for creams, ointments, gels, and other topical products when the quantity dispensed and daily gram use can be supported.
Things to know
Day supply = grams dispensed ÷ grams used per day
- Topical day supply often depends on body area, application amount, frequency, and pharmacy policy.
- Directions such as “apply as directed” or “apply to affected area” are not enough by themselves.
- Day supply calculations are for workflow support.
Example
Example:
60 grams dispensed at 2 grams/day = 30 days.
60 grams dispensed at 2 grams/day = 30 days.
Open tool
Adherence, Medication Remaining, and Medication Sync
What it does
These tools support refill planning, medication-on-hand review, and synchronization checks.
When to use it
Use them when comparing what the patient should have remaining, whether a short fill makes sense, or whether multiple medications can be aligned to a common date.
Things to know
- Medication Remaining estimates supply based on fill history, days supply, and elapsed time.
- Medication Sync helps estimate quantities needed to align medications to a target date.
- Adherence review can identify math concerns, but it does not prove how the patient actually used the medication.
Common mistakes
- Ignoring hospitalization, dose changes, discontinued therapy, lost medication, or partial fills.
- Assuming claim history always matches patient possession.
- Using sync math without checking payer rules and pharmacist guidance.
Open tools
Warfarin Weekly Dose
What it does
The Warfarin calculator totals a patient's weekly dose based on different tablet counts or strengths across the week.
When to use it
Use it when directions vary by day, such as different doses on Monday/Wednesday/Friday versus the rest of the week.
Things to know
Weekly dose = sum of each day's dose
- Warfarin directions can be complex and should be reviewed carefully.
- This tool supports arithmetic only; it does not evaluate INR, dose appropriateness, or clinical safety.
- Verify strength, schedule, and pharmacist guidance before relying on the result.
Example
Example:
5 mg on Monday, Wednesday, and Friday plus 2.5 mg on the other four days = 15 mg + 10 mg = 25 mg/week.
5 mg on Monday, Wednesday, and Friday plus 2.5 mg on the other four days = 15 mg + 10 mg = 25 mg/week.
Open tool
Pancreatic Enzyme Day Supply
What it does
The Pancreatic Enzyme calculator estimates day supply based on capsules used with meals and snacks.
When to use it
Use it when directions specify capsules per meal, capsules per snack, and the expected number of meals and snacks per day.
Things to know
Capsules/day = meal capsules + snack capsules
Day supply = capsules dispensed ÷ capsules/day
Day supply = capsules dispensed ÷ capsules/day
- Results depend on the number of meals and snacks entered.
- Directions with variable meals, snacks, or max daily caps need careful review.
- Verify against package size, directions, policy, and pharmacist guidance.
Example
Example:
2 capsules with 3 meals and 1 capsule with 2 snacks = 8 capsules/day. 240 capsules ÷ 8 = 30 days.
2 capsules with 3 meals and 1 capsule with 2 snacks = 8 capsules/day. 240 capsules ÷ 8 = 30 days.
Open tool
Refrigerated Shipment Check
What it does
The Refrigerated Shipment Check flags delivery dates that may create weekend, holiday, or shipping-delay concerns for temperature-sensitive medications.
When to use it
Use it before releasing or reviewing a cold-chain shipment when the proposed delivery date may be affected by weekends, holidays, or carrier timing.
Things to know
- This is a workflow warning tool, not a replacement for cold-chain policy.
- Carrier rules, packaging validation, temperature excursion procedures, and pharmacist or leadership guidance still apply.
- Different refrigerated products may have different stability requirements.
Common mistakes
- Looking only at ship date and ignoring delivery date.
- Forgetting carrier holidays.
- Shipping temperature-sensitive medication into a weekend without review.
- Assuming all refrigerated products have the same stability rules.
Open tool
Standard and Scientific Calculator
What it does
The standard calculator gives PharmCalc a built-in place for quick arithmetic without leaving the app.
When to use it
Use it for percentages, package totals, quantity checks, daily-use conversions, documentation verification, and other quick side math.
Things to know
- The standard calculator is intentionally general-purpose.
- It is useful when the task does not require one of the specialized pharmacy calculators.
- Use the dedicated calculators when assumptions, warnings, or copyable notes matter.
Open tool
Smart Fill Recognition
What it does
This section explains how Smart Fill recognizes common pharmacy directions and why it sometimes asks for manual review.
When to use it
Use this reference when you want to understand why a SIG matched a calculator, why a warning appeared, or why Smart Fill refused to guess.
Things to know
- Smart Fill is designed to be conservative when directions are incomplete.
- Manual review is a feature, not a failure, when the prescription lacks enough information.
- The goal is to prefill useful fields without hiding uncertainty.
Open tool
Frequently Asked Questions
Is PharmCalc a clinical decision tool?
No. PharmCalc is arithmetic and workflow support. It does not decide whether a medication is appropriate, safe, payable, or clinically correct.
Why does Smart Fill refuse some directions?
Because some directions do not contain enough information to calculate responsibly. “As directed,” incomplete sliding scales, unclear topicals, and unsupported weekly shorthand should be reviewed manually. Smart Fill also flags directions where a written strength doesn't match the recognized brand, where the route or dosage form doesn't match the medication (like an inhaled direction written for a nasal spray product), or where a generic name is shared by brands with different dosing and no brand name was written.
Why not put every reference on the homepage?
The homepage should stay fast and calculator-first. This Reference & How-To Guide carries the detailed explanations, formulas, examples, FAQs, and search-friendly content.
Can PharmCalc replace checking the claim?
No. Claim adjudication, payer rules, refill-too-soon messages, plan limits, and policy requirements still have to be reviewed in the pharmacy system.
Why are assumptions shown in the result?
Because hidden assumptions create bad confidence. If a calculation uses drops per mL, total actuations, max daily dose, threshold percentage, grams/day, or a 30-day monthly estimate, the user should be able to see and challenge that assumption.
What makes PharmCalc different from a basic pharmacy calculator?
PharmCalc combines calculators with workflow features: Smart Fill, MME Stacking, search, favorites, examples, history, copyable notes, assumptions, warnings, and reference documentation. The goal isn't just to calculate. It's to support real pharmacy workflow.