Sleep Debt Calculator

Sleep Balance

Across {{ dayCount }} night(s)

Need {{ formatFixed(sleepNeedValue, 2) }} h/night Avg {{ formatFixed(avg_hours, 2) }} h Gross {{ formatFixed(gross_deficit, 2) }} h Credit {{ formatFixed(oversleep_credit, 2) }} h {{ catchup_days }} day plan Round {{ roundingBadgeText }} Cap {{ deficitCapBadge }} {{ creditModeBadge }}

Enter your nightly sleep need and at least one recent night to calculate the current debt.

Preset:

Sleep need:

h/night

Horizon:

Recent nights

{{ row.label }}:

Allow oversleep credit:

Nightly deficit cap:

Round entries to nearest:

min

Max extra per day:

Nap allowance:

Metric	Value	Copy
Nights	{{ dayCount }}
Sleep need	{{ formatFixed(sleepNeedValue, 2) }} h/night
Total sleep needed	{{ formatFixed(sleepNeedValue * dayCount, 2) }} h
Total slept (rounded)	{{ formatFixed(total_slept, 2) }} h
Average per night	{{ formatFixed(avg_hours, 2) }} h
Gross deficit	{{ formatFixed(gross_deficit, 2) }} h
Oversleep credit applied	{{ formatFixed(oversleep_credit, 2) }} h
Net sleep debt	{{ formatFixed(net_debt, 2) }} h ({{ debt_readable }})
Deficit cap	{{ deficitCapDescription }}
Rounding rule	{{ roundingDescription }}
Credit mode	{{ creditModeDescription }}
Max extra per day	{{ formatFixed(maxExtraValue, 2) }} h
Nap allowance	{{ formatFixed(napValue, 2) }} h
Catch-up capacity per day	{{ formatFixed(perDayRecovery, 2) }} h
Catch-up days (est.)	{{ catchup_days }}

Night	Slept (h)	Need (h)	Deficit (h)	Credit used (h)	Cum. debt (h)	Copy
{{ r.label }}	{{ formatFixed(r.slept, 2) }}	{{ formatFixed(r.need, 2) }}	{{ formatFixed(r.deficit, 2) }}	{{ formatFixed(r.creditApplied, 2) }}	{{ formatFixed(r.cumDebt, 2) }}

Day	Night extra (h)	Nap extra (h)	Remaining debt (h)	Copy
{{ r.day }}	{{ formatFixed(r.nightExtra, 2) }}	{{ formatFixed(r.napExtra, 2) }}	{{ formatFixed(r.remaining, 2) }}

Chart uses cumulative debt after each night using the rounding, cap, and credit settings above.

Enter your nightly log to generate sleep debt metrics, charts, and exports.

Tags: Date Time , Sleep Hygiene

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Sleep debt is the running gap between the sleep your body needs and the sleep you actually get across recent nights. That makes a simple weekly sleep debt tracker useful for seeing patterns and deciding how to adjust.

You provide a nightly target and a short log of recent nights, then read a clear total with averages and a day count. A seven or fourteen night view shows how small changes add up over time and points to a practical next step.

A quick example helps. With a target of 8 hours, a 6 hour night followed by a 9 hour night still leaves a balance, so you know whether to add time tonight or plan naps.

Numbers can be rounded to consistent minute blocks for cleaner comparisons, and a nightly cap prevents one extreme from dominating the total. You may also let surplus nights reduce what you owe so the balance reflects steadier habits.

Treat results as planning guidance, not medical advice. This tool provides informational estimates and does not substitute professional advice.

Technical Details:

The calculator observes nightly sleep duration and a personal sleep need, then summarizes the difference across a fixed horizon. It computes a per‑night deficit, applies an optional cap, optionally applies credit from surplus nights, and reports the cumulative balance at the most recent night.

Gross deficit is the sum of nightly shortfalls after capping. Oversleep credit is the portion of surplus applied to reduce the running balance. Net sleep debt is the final cumulative value after all nights in scope. A simple catch‑up estimate divides the balance by planned extra time per day from longer nights and optional naps.

Comparability depends on consistent horizon and rounding. Rounding is applied to nightly entries before any other step. Turning credit on or off and changing the nightly cap will change both the totals and the shape of the debt curve.

p i_{raw} = x i_{h} p i = {\begin{cases} \frac{m \cdot round (\frac{p i_{raw} \cdot 60}{m})}{60} & if m > 0 \\ p i_{raw} & if m = 0 \end{cases}} d i = \min (\max (0, H - p i), C) s i = \max (0, s i−1 + d i - c i), s 0 = 0 c i = {\begin{cases} \min (\max (0, p i - H), s i−1 + d i) & if credit on \\ 0 & if credit off \end{cases}} D = s N, G = \sum_{}^{} d i, A = \sum_{}^{} c i r = X + Y, days = {\begin{cases} ceil (\frac{D}{r}) & if D > 0 and r > 0 \\ 0 & otherwise \end{cases}}

Symbols and units used
Symbol	Meaning	Unit/Datatype	Source
N	Horizon nights	integer	Input
x_i	Raw nightly sleep	hours	Input
m	Rounding block	minutes	Input
p_i	Rounded nightly sleep	hours	Derived
H	Sleep need per night	hours	Input
C	Nightly deficit cap	hours	Input
d_i	Nightly deficit	hours	Derived
c_i	Credit applied	hours	Derived
s_i	Cumulative debt	hours	Derived
G	Gross deficit	hours	Derived
A	Oversleep credit sum	hours	Derived
D	Net sleep debt	hours	Derived
X	Planned extra at night	hours/day	Input
Y	Planned nap time	hours/day	Input
r	Catch‑up capacity	hours/day	Derived

Worked example

Inputs: N = 3, H = 8.0 h, m = 0, C = 2.0 h, credit on

Oldest→recent nights: 6.0, 9.0, 7.0 h

d 1 = \min (2.0, 2.0) = 2.0 h, c 1 = 0, s 1 = 2.0

d 2 = 0, c 2 = \min (1.0, 2.0) = 1.0, s 2 = 1.0

d 3 = 1.0, c 3 = 0, s 3 = 2.0 h

G = 3.0 h, A = 1.0 h, D = 2.0 h

r = 1.5 + 0.5 = 2.0 h/day, days = ceil (\frac{2.0}{2.0}) = 1

Interpretation: a 2 h balance clears with one day of 2 h planned recovery.

Units, precision & rounding policy

Inputs are hours with a decimal point; minute rounding is applied before analysis.
Rounding uses standard half‑up behavior from the platform’s round function.
Displayed values commonly show two decimals; readable “h m” is also provided.

Validation & bounds

Input validation and bounds
Field	Type	Min	Max	Step/Pattern	Notes
Horizon	select	7	14	7 or 14	Fixed choices
Sleep need	number	4	12	0.1	Sanitized to non‑negative in code
Nightly entries	number	0	24	0.1	Decimals allowed; rounded if enabled
Nightly deficit cap	number	0	8	0.1	Clamped to 0–12 in code; 0 means unlimited
Rounding minutes	number	0	60	5	0 disables rounding
Oversleep credit	boolean	—	—	—	Applied up to running balance
Max extra per day	number	0	6	0.1	For catch‑up plan
Nap allowance	number	0	4	0.1	For catch‑up plan

I/O formats

Inputs and outputs
Input	Accepted Families	Output	Encoding/Precision	Notes
Hours per night	Numbers	Summary table	Two decimals	Copy or download CSV; DOCX export
—	—	Daily breakdown	Two decimals	Copy or download CSV; DOCX export
—	—	Catch‑up plan	Two decimals	Copy or download CSV; DOCX export
—	—	JSON payload	Structured fields	Copy or download JSON
—	—	Debt chart	Rounded values	Cumulative after each night

Networking & storage

Processing is browser‑based; copying, downloads, and charting run on the client.
One external script is referenced for the charting layer; metrics render even if it is blocked.
No user entries are transmitted to a server by the calculator.

Assumptions & limitations

Sleep need is treated as constant over the selected horizon.
Sleep quality, timing, and fragmentation are not modeled.
Only planned naps are included in the catch‑up estimate, not in nightly logs.
Older nights beyond the horizon are ignored.
Rounding can slightly inflate or deflate totals depending on block size.
Heads‑up Large nightly caps can hide severe shortfalls; small caps can understate challenging nights.
Oversleep credit never exceeds the current running balance.
Catch‑up plan length is bounded to a practical limit of 60 days.

Edge cases & error sources

Non‑numeric or negative inputs are sanitized to zero before use.
Deficit cap values are clamped to a safe range; entering very large numbers has no extra effect.
Rounding minutes over the limit are clamped; zero disables rounding.
Extremely long nights are bounded by the nightly input limit.
If catch‑up capacity per day is zero, days to clear is reported as zero.
Floating‑point rounding may produce small visual differences versus mental math.
Chart unavailable when the external chart script cannot load; tables and exports still work.
Clipboard or download permissions can fail due to browser policies.
Locale settings that change decimal separators may affect input parsing.
Rapid edits are debounced; the chart updates after a short delay.

How to Use:

Sleep debt estimation compares your target to recent nights and produces totals, a chart, and an optional catch‑up plan.

Enter your sleep need in hours per night.
Choose a horizon of 7 or 14 nights.
Fill recent nights starting with the most recent at the top.
Optionally set rounding, a nightly cap, and enable oversleep credit.
Set planned max extra per day and nap allowance to see a catch‑up plan.
Review the summary, daily table, plan, chart, or JSON as needed.

Example: Need 8.0 h, horizon 7, rounding off, cap 2.0 h, credit on, extra 1.5 h, naps 0.5 h.

Tip: keep rounding consistent to compare weeks cleanly.

FAQ:

Is my data stored?

No. Calculations and exports run on your device, and entries are not sent to a server. The chart script may load from an external source.

If that script is blocked, charts are skipped but tables remain.

How accurate is the balance?

It sums hours below your target after optional rounding and caps, then subtracts applied credit. It does not assess sleep quality or timing.

What units can I enter?

Enter hours with a decimal point. Minute rounding applies first, then deficits and credits are calculated with two‑decimal displays.

Can I use it without a connection?

Metrics and exports work once loaded. The chart depends on an external script and may be unavailable if the connection drops.

What does zero debt mean?

A zero balance means your rounded nights met or exceeded your target after credit rules. It is not a guarantee of ideal rest or alertness.

How do I get a catch‑up plan?

Set max extra per day and optional naps. The plan allocates those hours until the running balance reaches zero, up to a 60‑day limit.

Does it cost anything?

No licensing terms are included here. Availability and terms depend on where this calculator is hosted.

Glossary:

Sleep need (H): Target hours of sleep per night for comparison.
Horizon (N): Number of recent nights included in the balance.
Nightly deficit: Portion of need unmet after rounding and capping.
Oversleep credit: Surplus applied to reduce the running balance.
Gross deficit: Sum of nightly shortfalls before credit.
Net sleep debt: Final cumulative balance after all nights.
Catch‑up capacity (r): Planned extra per day from nights and naps.