What the Time-Space percentage is
If you run a family day care (home daycare) business from your residence, you may deduct certain home expenses under the business-use-of-home rules. For daycare providers who regularly use space for care and meet the IRS daycare facility conditions, Publication 587 describes a daycare facility approach that combines:
- Space % — how much of your home’s square footage is used for daycare (exclusive vs regular shared use), and
- Time % — how many hours the home was used for daycare versus hours available in the tax year.
Those pieces combine into a single Time-Space percentage that often feeds Form 8829 (Expenses for Business Use of Your Home), commonly discussed as the line 7–style business percentage for daycare. Always follow the current Form 8829 instructions for your tax year.
Who this method is for
In plain terms, this path is aimed at providers who:
- Care for children in their home as a business,
- Regularly use parts of the home for that care, and
- Qualify under the daycare facility rules in Pub. 587 (including licensing/approval or exemption conditions — check the publication for your situation).
If you only claim a room used exclusively and regularly for business under the regular home-office rules (not daycare), the math differs. When in doubt, ask your tax pro which method applies.
Step-by-step calculation
1. Measure the home
Start with total finished living space of the home in square feet (the same basis you would use consistently for Form 8829). Exclude outdoor space you do not treat as part of the home’s interior square footage under the instructions you follow.
2. Split daycare space into exclusive vs regular use
- Exclusive-use daycare space — areas used only for the daycare business (for example a playroom that is never personal living space). Exclusive space generally counts at 100% of its share of the home toward the business percentage (it is not multiplied by the time percentage).
- Regular-use shared space — rooms used for daycare on a regular basis but also for personal living (living room, kitchen, dining area). That square footage is multiplied by the time percentage.
Do not invent “exclusive” status for a shared family room. Auditors and preparers look for a defensible story.
3. Log daycare hours for the year
Pub. 587 allows hours the home is used for daycare, including ordinary and necessary prep and cleanup related to the daycare, not only hours children are present. Typical buckets providers track:
- Hours children are in care
- Prep and cleanup
- Extra daycare days / evenings
- Business tasks done in the home for the daycare (when allowed under the publication’s framework)
Keep a contemporaneous log (calendar, attendance + hours sheet, or workbook). Reconstructing a year from memory is fragile.
4. Compute time %
Hours available are generally 24 × days in the tax year (8,760 in a non-leap year), or a shorter available period if you started or stopped mid-year under the rules you apply.
5. Combine into Time-Space %
That Time-Space % is the figure many providers use as the business percentage on Form 8829 (verify the exact line mapping for your year’s form).
Free Time-Space calculator
Run the same daycare-facility style math in your browser — exclusive vs regular rooms, hours, mid-year start/stop. No account required.
IRS Pub. 587 Example 1 (self-check)
Publication 587 includes worked examples. One common self-check (Example 1 style figures used in our calculator tests):
- Home: 3,200 sq ft
- Regular daycare space: 1,600 sq ft (no exclusive in that example)
- Daycare hours: 3,000
- Hours available: 8,760
Time % = 3,000 ÷ 8,760 ≈ 34.25%. Time-Space % = 50% × 34.25% ≈ 17.12%. Our calculator includes a chip to load this example so you can verify the tool matches the publication’s arithmetic pattern.
Common mistakes
- Calling shared rooms “exclusive”
- Forgetting prep/cleanup hours that are ordinary and necessary for the daycare
- Using 365 days of availability when you only operated part of the year (or the reverse)
- Mixing simplified home-office method assumptions with daycare Time-Space without guidance
- No square-footage sketch or hours log to support the return
What to do with the percentage
- Save your inputs (sq ft by room, hours totals, tax year).
- Apply the percentage to allowable home expenses as Form 8829 / Pub. 587 direct.
- Carry results into your Schedule C workflow with your preparer.
- Keep records with your tax file (see our audit records guide).
For year-round tracking, the NaptimeLedger Daycare Tax Workbook embeds the same Time-Space logic plus meals, mileage, and Schedule C / 8829-oriented summaries.
Sources
- IRS Publication 587, Business Use of Your Home
- About Form 8829 and current Form 8829 instructions