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Skylight Opening Size Calculator
Size a roof opening for a skylight frame.
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Size a roof opening for a skylight frame.
Skylight Opening Size Estimator
Enter your numbers below for an instant estimate.
0
π‘ Tip: Add clearance.
How It Works
Key concepts behind this calculator
1
Enter Values
Fill in each field with your own numbers.
2
Calculate
Results update as you change the inputs.
3
Review
Read the breakdown and the explanation.
4
Adjust
Change values to compare scenarios.
Quick Reference Guide
Skylight Quick Guide
Typical values for reference.
| Frame | Gap | X | Opening |
|---|---|---|---|
| 55×78 | 1.5 cm | – | 58 x 81 cm |
| 78×98 | 1.5 cm | – | 81 x 101 cm |
| 94×118 | 2 cm | – | 98 x 122 cm |
| 114×140 | 2 cm | – | 118 x 144 cm |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Common Questions
Skylight Opening Size Calculator FAQ
Answers to common questions about this calculator.
Frame plus gap.
It gives a quick estimate of skylight opening size from the values you enter.
No. It is a planning estimate, so check important figures with a professional or official source.
Yes. Edit any field and the result updates when you calculate.