Free CPAP planning tool
Use any brand's prices, your spare stock and your own replacement schedule to build a practical supply budget.
Stock covers all replacements in this period.
Understand your plan
Cost per unit is your pack price divided by the number of units in that pack. The daily average is the unit cost multiplied by units per replacement, divided by your chosen interval in days.
Annual average = daily average × 365
Monthly average = annual average ÷ 12
We count replacement dates from your next replacement up to, but not including, the plan end date. Existing unused units cover those replacements first. Any remaining need is rounded up to whole packs.
Units to buy = max(0, units needed − spare stock)
Packs to buy = round up(units to buy ÷ units per pack)
Suppose a pack of 6 filters costs $12, you use 1 at each replacement, your chosen interval is 30 days, your next replacement is in 10 days, and you have 2 unused filters. A 90-day plan contains 3 replacement dates. You need 1 additional filter, so you buy 1 pack for $12 and finish with 5 spare filters. The ongoing monthly average is about $2.03 and the annual average is about $24.33. This is an arithmetic example, not a recommended filter schedule.
The first replacement not fully covered by stock determines the first shortage date. We subtract your order-ahead days to get a planning deadline. A deadline on or before the start date is shown at plan start. The reminder covers your calculated whole-pack purchase for the full period; it is not a recurring automatic order.
Use the instructions for your exact equipment and advice from your equipment provider. Inspect equipment as instructed and respond to damage or wear rather than relying only on a date. Insurance reimbursement schedules are separate from maintenance instructions; this tool does not determine eligibility or prescribe replacement intervals.
Count unused individual pieces available for future replacements. Exclude anything currently in use. Enter how many days remain until its next scheduled replacement separately. If you need two pieces at each replacement, enter two under units used at each replacement.
The average spreads ongoing use over a 365-day year and 12 equal budget months. Planned purchases depend on the exact period, replacement dates, existing stock and whole-pack sizes. A plan can cost zero to purchase even when ongoing usage has a cost.
No. Enter every price in the selected currency. The currency selector changes the displayed unit only, so check or re-enter prices when changing it. This tool does not calculate insurance payments, exchanges, tax or delivery charges separately.
Download the .ics file and import it into your calendar. It contains an all-day order event for each item that needs a purchase, with a one-day-before alert. Your calendar controls notifications and may change or ignore imported alerts. If an order is already due at plan start, set a reminder that works for you. No emails, text messages or orders are sent by this page.
The calculator keeps inputs only in this open page. A reset or reload clears them. You can keep a CSV or printed copy yourself; the calculator does not store a supply history or transmit these inputs to site analytics.
The arithmetic uses your inputs. Manufacturer information helps distinguish equipment care from insurance schedules.
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