TOOLS · CALCULATOR

CPAP compliance calculator

The usual US insurance rule is 4 hours of CPAP use on 21 of 30 consecutive nights, inside your first 90 days. This CPAP compliance calculator shows whether you are there, how many nights you still need and how many you can miss.

About 1 minute
Free, no sign-up

Free CPAP compliance calculator: check the 4-hour, 70%-of-nights rule, see nights still needed, nights you can miss and your best 30-day window.

5 questions · nothing leaves your device

YOUR RESULT

What your result looks like

A sample result. Yours appears here the moment you finish, with what it means and what to do next. Every possible result is listed beside it.

Your resultAt risk

1/21

021

At risk: you need {needed} of the next {future} nights at 4 hours.

You can still qualify in this window, with almost no slack. Fix whatever is cutting nights short now.

Check mask fit and leak
Ask your DME about comfort settings

21–+Qualified
Qualifying window found: {start} to {end}, {count} of 30 nights at 4 hours.
Either side of 10000On track
On track: {needed} more 4-hour nights and you qualify. You can miss up to {can_miss}.
Either side of 10000At risk
At risk: you need {needed} of the next {future} nights at 4 hours.
Either side of 10000Behind
This window can't reach 21, but one starting by {next_start} still can.

Use the calculator

Quick check takes a minute. Night by night is exact. If you upload your card to Apnealytics, your own data fills it in.

What this tool does

It checks one rule: 4 hours or more on 70% of nights in some 30 consecutive days within your first 90. It is for people whose insurer or DME is watching usage. It cannot tell you your insurer's exact policy or whether therapy is working.

How the score works

Item	Rule
Compliant night	4.0+ hours on the machine's sleep day
Qualifying window	21+ compliant nights in 30 consecutive days
Period	Window fully inside days 1–90 (61 possible windows)
Still needed	21 minus compliant nights in your best window
Can still miss	Future nights in that window minus still needed
Status	Qualified · On track (miss 3+) · At risk (miss 0–2) · Behind

Reading your result

Qualified. A window has 21 or more 4-hour nights. Note the dates; your DME will ask.

On track. Your window can still reach 21 with three or more nights to spare.

At risk. You can still make it, but only just. Every night counts.

Behind. This window cannot reach 21. A later one may still fit before day 90. If none can, call your DME now, not at day 89.

Let your own data do the counting

Checking 61 overlapping windows by hand is slow. Use my data reads each night's usage from your card and finds the best window, with the same logic as the compliance report autopilot, which on Pro turns it into a letter. The dashboard streak keeps the 4-hour line in view.

Sources

CMS. LCD: Positive Airway Pressure Devices for the Treatment of Obstructive Sleep Apnea (L33718).
Kribbs NB et al. Objective measurement of patterns of nasal CPAP use. Am Rev Respir Dis, 1993.
Weaver TE et al. Hours of CPAP use and normal levels of sleepiness and daily functioning. Sleep, 2007.

FAQ

What is the CPAP 90-day compliance rule?

Under Medicare's coverage policy you must use CPAP for at least 4 hours a night on at least 70% of nights, 21 of 30, in a consecutive 30-day window within your first 90 days. Many private insurers use the same or a similar rule. A clinician also documents at follow-up that therapy is helping.

Does the 30-day window have to start on day 1?

No. Any 30 consecutive days inside your first 90 can qualify, so days 15 to 44 work as well as days 1 to 30. The calculator checks every window and reports the earliest that reaches 21 compliant nights, so a slow first week is not the end of the story.

Do nights under 4 hours count?

Not toward the 21. A night of 3 hours 50 minutes is non-compliant, even though it still helped your breathing. If nights keep ending just short, look at mask comfort, leak and ramp settings, and talk to your DME about what can be adjusted.

Why does my result differ from my DME's report?

Usually the start date differs, a "night" is defined differently, or the DME's modem data has gaps. Apnealytics uses your start date and your machine's sleep day. Ask your DME which date is day 1, then compare the same 30 days.

Is this calculator free?

Yes. Quick check and night by night need no account. Use my data works with your uploaded card; Pro keeps full history and drafts the compliance letter. See pricing.