The shade should relate to table width and stay visibly inside the edge so guests do not meet the glass when standing up.
Start with the problem, not the product photograph
A few centimetres can expose a bulb or put glass in a door path. For Pendant diameter over a dining table, measure the complete three-dimensional envelope.
Photograph the proposed position straight on and from the side. Record the full dimensions, lampholder, bulb, connection method and the main task. A close product image rarely shows room scale, door movement or the angle from which a bare bulb becomes visible.
Three distinct decisions
1. Decide the job before the style
Keep the pendant centred on the furniture, not automatically on the room, and preserve a clear visual margin around the shade.
Keep this evidence: write the main task and the one constraint that could rule the fitting out.
2. Measure the real fitting envelope
Measure table width and length, shade diameter and the path of a seated person’s head and shoulders when rising.
Keep this evidence: record every dimension from one named reference point and photograph the tape measure in place.
3. Test the result from normal positions
Hang a circular template, set the table and have people sit and stand from every place before approving the diameter.
Keep this evidence: repeat the check by day and after dark, using the bulb and furniture layout you expect to keep.
Worked calculation
Table-edge margin
M = (T − D) ÷ 2
Variables: M is the visible margin on each side, T is table width and D is shade diameter, all in millimetres.
Example: For a 1000 mm table and 406 mm shade, M = (1000 − 406) ÷ 2 = 297 mm per side. Test that 297 mm with people standing from the chairs.
The calculation gives a planning check, not an installation approval. Confirm the maker’s dimensions, use a full-size mock-up and let the appropriately qualified person decide structural and fixed-wiring details.
A real TiffanyLight.co.nz product as the worked case
30 cm European stained-glass pendant
A medium pendant used for canopy, height, table alignment and total-cost examples.
This model demonstrates the method; it is not an automatic recommendation. Draw its complete dimensions, verify the current electrical specification and test the proposed light in the real room. Product details can change, so check the live page before buying.
Confirm on the product page: total dimensions, weight, voltage and connection, lampholder, maximum wattage, included parts and installation conditions.
Practical New Zealand home scenario
Build the full shade diameter in lightweight card and place it at the stated height. Photograph it from the doorway, seat and closest route. Add a realistic margin; a choice that works only to the millimetre will fail when furniture moves or installation tolerances appear.
Common mistakes
- Confusing shade diameter with total fitting width.
- Forgetting doors, heads, curtains, cupboards and cleaning access.
- Rounding inch dimensions before drawing the template.
Final checklist
- All dimensions use the same reference point.
- The complete volume is mocked up at 1:1.
- Doors and walking routes remain clear.
- Seated and standing views are tested.
- Safe service access exists.
Record sheet: model, complete dimensions, total weight, voltage and connection, lampholder, chosen LED, position, mock-up photograph and check date. The current product information and maker’s instructions take priority over general guidance.