Storage & Shelving
Shelf Spacing Calculator
Space your shelves evenly. Enter the total height, shelf thickness and the clear gap you need, and we calculate how many shelves fit and the exact spacing between them.
Last updated: June 2026
Why shelf spacing matters
Correct shelf spacing prevents buying a unit only to find it doesn't fit your books or appliances. It also affects structural performance: too few shelves means long spans prone to sagging.
Formula used
Usable height = total height β (top padding + bottom padding)
Number of shelves = floor((usable height + clear gap) / (shelf thickness + clear gap))
Actual clear gap = (usable height β n Γ shelf thickness) / (n β 1)
Worked examples
200 cm bookcase, 1.8 cm shelves, 28 cm gap: n = floor((196 + 28) / (1.8 + 28)) = 7 shelves. Actual gap = 30.3 cm.
90 cm alcove, 2 cm shelves, 20 cm gap (spices): n = floor(110 / 22) = 5 shelves. Gap = exactly 20 cm.
How to use this calculator
- Measure the total height of the unit or alcove.
- Decide on shelf board thickness.
- Measure your tallest item and add 2β3 cm for the minimum clear gap.
- Note any top or bottom trim and enter as padding.
Clear gap guide by item type
| Item type | Typical height | Recommended gap |
|---|---|---|
| Paperback books | 18β22 cm | 24β26 cm |
| Hardback books | 24β28 cm | 30β32 cm |
| A4 ring binders | 30 cm | 33β35 cm |
| Kitchen plates | 3β5 cm | 8β12 cm |
| Glasses / mugs | 10β15 cm | 18β22 cm |
Notes & limitations
For adjustable shelving with pin holes, use the actual gap as a guide and set pins to the nearest 3.2 cm increment. Related: Wardrobe Storage Calculator.
Frequently Asked Questions
How far apart should bookshelves be?
Standard paperback books are 20β22 cm tall; hardbacks are 24β30 cm. A clear gap of 25β28 cm accommodates most paperbacks; 30β33 cm suits hardbacks. Oversized art books need 35β40 cm.
How many shelves fit in a 200 cm bookcase?
With 1.8 cm thick shelves and 28 cm clear gaps: 7 shelves with a 27.2 cm gap. With 2 cm thick shelves and 30 cm gaps: 6 shelves.
What thickness should shelf boards be?
For spans up to 60 cm: 18β22 mm MDF or solid wood. For 60β90 cm spans: 22β25 mm minimum to avoid sagging. For 90β120 cm spans: 30β38 mm.
Should shelves be evenly spaced?
Evenly spaced shelves are structurally balanced and visually clean. Variable spacing is common for display shelving where different item heights mix.
How do I calculate spacing for floating shelves?
Use the same formula. Measure the total wall height to be used as 'total height'. Include any bracket depth in 'shelf thickness'.