The small wording difference
Four weeks is 28 days. A calendar month is not always four weeks. When a service advertises a price “per month,” look for the definition in its checkout and terms. Shed’s terms, for example, state that billing can occur every 28 days or monthly depending on the program. That does not establish the cadence of every Shed offer; it establishes why the selected plan needs its own answer. Write the payment period next to the price before making any comparison.
Source: Shed: program-specific billing and subscription terms
Compare equal lengths of time
Consider a hypothetical service charging $200 every 28 days. Thirteen periods cost $2,600 and cover 364 days. Twelve periods cost $2,400 but cover only 336 days. A separate hypothetical service charging $200 per calendar month costs $2,400 across twelve calendar months. These examples compare the arithmetic only: they do not say the services include equivalent care or medication. Counting twelve four-week payments as a full year would leave 28 days out of a 364-day comparison.
Convert to an annualized estimate
For a continuous-cost estimate over a 365-day year, multiply the 28-day price by 365 and divide by 28. At $200, that is approximately $2,607.14 per year, or $217.26 per average calendar month when divided by twelve. Compared with $200 per calendar month, the annualized rate is approximately 8.6% higher. This is a budgeting conversion, not a prediction that the provider will collect fractional payments. Use it to compare rates, then examine the real renewal calendar to understand cash flow.
Do not confuse a rate with a payment schedule
If a subscription charges at the start of every 28-day period, payment dates fall on days 0, 28, 56 and so on. Day 364 starts the next period. A date range that includes both the opening charge and day 364 can therefore contain fourteen charges, with the final charge buying service extending beyond that range. There is no contradiction with thirteen periods equaling 364 days. One statement describes the periods consumed; the other counts advance payments inside a chosen window. State the window and treatment of the first payment explicitly.
Keep supply and billing in separate columns
A pharmacy supply period and a care subscription period can differ. Record three things: when money is collected, how much service or medication that purchase covers, and the earliest next renewal. Do not infer a dosing schedule from a billing schedule. Use the clinician’s and pharmacy’s instructions for treatment. If a plan says six months, ask for the number of days or weeks included and the actual end date. Request the same information for any medication refill rather than assuming a marketing label describes the whole package.
Budget for promotions without hiding the change
Suppose the first 28-day period costs $100 and the next twelve cost $200 each. Thirteen periods then cost $2,500 for 364 days. That is different from both a permanent $100 rate and a permanent $200 rate. Show the promotion, renewal rate and number of discounted periods separately. If an advertised saving depends on prepayment, add the amount due today and the cancellation terms. An average can be helpful, but it should not conceal a large initial payment or a short introductory window.
The three questions to send a provider
Ask: “Is this price charged every 28 days or on the same date each calendar month? How many days or weeks does each payment cover? What are my next three charge dates?” Save the response with the selected plan name. This simple record is more useful than trying to infer the contract from a price badge. Compare those answers with the provider review and complete cost breakdown before choosing which service fits your budget.
Put the questions to work
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Sources & scope
Sources checked October 12, 2026. This guide explains published information and consumer research questions; it is not a clinical evaluation.
Prices and terms can change. Confirm your specific offer directly with the provider.