Dial in slat pitch for tidy plant rooms. See counts, stack height, and cut notes. Build shade projects that fit, lift, and last well.
Use this table to sanity-check typical values for small garden structures.
| Scenario | Finished Height (in) | Slat Height (in) | Overlap (%) | Rail Deduction (in) | Estimated Slat Count |
|---|---|---|---|---|---|
| Greenhouse vent window | 36 | 1 | 10 | 3.5 | 37 |
| Potting shed door lite | 48 | 1 | 12 | 4.0 | 50 |
| Propagation rack side shade | 60 | 1 | 8 | 3.0 | 63 |
1) Effective coverage height
EffectiveCoverage = FinishedHeight − (TopRailDeduction + BottomRailDeduction) + ExtraAllowance
2) Effective slat pitch
Pitch = SlatHeight × (1 − Overlap%)
3) Slat count
SlatCount = Rounding( EffectiveCoverage ÷ Pitch )
4) Raised stack estimate
Stack ≈ (SlatCount × SlatThickness) + RailStackAllowance, adjusted for garden environment.
Mini blinds used as garden shades must cover glass consistently to limit heat spikes, protect seedlings, and reduce algae growth on glazing. A correct slat count prevents light leaks at the bottom and avoids overstacking that blocks vents when the blind is raised. This improves uniformity across benches and reduces swings. In humid rooms, small sizing errors amplify because cords stretch and rails swell slightly.
Overlap is the portion of each slat that sits over the next one when closed. Higher overlap tightens the effective pitch, increasing slat count and improving glare control for south-facing panels. Lower overlap reduces count and cost but may leave thin sun lines at midday. Many growers start around 10% and adjust after observing leaf scorch patterns.
The headrail, tilt mechanism, and bottom rail occupy space that slats cannot cover. Deductions keep your slat field aligned with the visible opening, especially on vent windows with hardware brackets. When mounting inside a frame, measure the usable clear height, then subtract rail bulk and add a small allowance for seals or clips that keep dust out.
Raised stack height is driven by slat thickness, count, and rail bulk. The calculator adds an environment factor because grit and moisture increase friction and stacking irregularity over time. If you need maximum airflow near roof vents, aim for a smaller stack by reducing overlap, choosing thinner slats, or splitting one tall opening into two shorter blinds.
For wet zones, prefer corrosion-resistant hardware and wipeable slats that tolerate dilute disinfectants. Keep tilt cords away from mist nozzles and fertiliser splash. Record your final count and pitch in the downloadable report so replacements match later. Stock one or two spare slats per blind; quick repairs prevent gaps that invite pests and uneven light.
A 1 inch (about 25 mm) slat is common and easy to source. Use smaller slats for tight frames and larger slats when you want fewer parts and faster cleaning.
Rounding up helps prevent a shortfall at the bottom edge when rails settle or cords stretch. A single extra slat is usually cheaper than reworking a blind that comes up short.
Many setups perform well between 8% and 15%. Increase overlap for harsh glare or sensitive seedlings, and decrease overlap when you need a smaller raised stack near vents.
Measure the headrail and bottom rail depth in the same unit as your height. If you cannot measure, start with 2.0 plus 1.5 inches and refine after a dry fit.
The count formula stays the same, but humidity can affect operation and stacking. That is why the stack estimate includes an environment factor and the notes recommend spare slats.
Yes. Select your unit at the top, then enter all measurements in that unit. The calculator converts internally and reports results in the same unit you selected.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.