LifeTally

Items in a row calculator

How many identical items fit in one usable length with your chosen gap only between neighbours?

Find the whole item count, number of gaps, occupied length and remainder for a row starting at one edge.

Your row dimensions

Use the same centimetre basis for all three measurements. L is already the usable length after any outer allowances you choose. All three inputs must be valid, even when no item fits; an invalid gap or item length leaves the results unknown.

Usable row length L, cmLength of each item w, cmYour gap between adjacent items g, cm

How the estimate works

Place identical items from one edge. There is a gap only between neighbours, with no gap before the first or after the last item. If L < w, the count and occupied length are zero and the remainder is L. Otherwise floor((L + g) ÷ (w + g)) gives the largest whole count n. There are n − 1 gaps, occupied length is n × w + (n − 1) × g, and the remainder stays at the far edge. A zero gap means touching items; the row is not centred and gaps are not redistributed.

L < w: n = 0; k = 0; U = 0; R = L
L ≥ w: n = floor((L + g) ÷ (w + g))
n ≥ 1: k = n − 1; U = n × w + k × g; R = L − U

This is a declared one-dimensional geometry model using your own constant item length and gap, not a recommended clearance. It does not model cutting or saw kerf, mixed item sizes, two- or three-dimensional packing, tolerances, installation, loads or safety. It does not guarantee physical fit. Check actual usable dimensions and your own requirements.

OpenStax: meaning of floor ↗

Check the filled example

Chosen example: L = 100 cm, w = 18 cm, g = 3 cm. Four items and three gaps occupy 4 × 18 + 3 × 3 = 81 cm, leaving 19 cm. Adding a fifth item needs another gap and item: 21 cm, so it does not fit. These are example inputs, not a spacing standard.

Accepted input values

Usable row length L, cm: 100
Length of each item w, cm: 18
Your gap between adjacent items g, cm: 3

Plan the next step

Convert your measurements to the same unit before comparing lengths. The unit converter can help; it does not choose a suitable gap.

Open unit converter →