Clothesline Length Calculator
Calculate the minimum clothesline length needed based on the number of items and their average width.
Plan your outdoor or indoor drying setup.
Clothesline length and capacity depend on the number of items you want to hang, the space each item requires, and the sag factor when a load is applied to the line.
Total line length formula: Line Length = (Items × Width per Item) + (Spacing × (Items − 1)) + 2 × End Allowance
Sag compensation (catenary sag formula approximation): Sag = (Load Weight × Span²) ÷ (8 × Line Tension)
For practical purposes, add 10–15% to your calculated line length to account for sag when weighted.
Variable definitions:
- Items — total number of clothing pieces to hang simultaneously
- Width per Item — average hanging width in inches: shirts ~12″, pants/jeans ~14″, sheets ~24″, socks ~4″ per pair, towels ~18″
- Spacing — minimum gap between items for airflow and prevent touching: 2–4 inches recommended
- End Allowance — extra line at each anchor point for tying: 6–12 inches per end
- Load Weight — total weight of wet laundry (wet clothing is 60–80% heavier than dry)
Drying time estimates by fabric type (moderate sun, light breeze):
- Cotton shirts: 1.5–3 hours
- Jeans/denim: 3–5 hours
- Towels: 2–4 hours
- Bed sheets: 2–3 hours
- Synthetic fabrics (polyester, nylon): 1–2 hours
- Wool (lay flat — do NOT hang): 4–8 hours flat-drying
Environmental drying factors:
- Temperature: higher = faster (doubles roughly every 10°C increase)
- Humidity: lower RH = significantly faster; above 85% RH drying nearly stops
- Wind: even light breeze (3–5 mph) cuts drying time by 30–50%
- Direct sunlight: UV kills bacteria but can fade colors — use shade for delicate items
Worked example: You want to hang one load of laundry: 5 shirts (12″ each), 2 pairs of jeans (14″ each), 4 pairs of socks (4″ each), 2 towels (18″ each). Total items: 13.
- Total hanging width: (5×12) + (2×14) + (4×4) + (2×18) = 60 + 28 + 16 + 36 = 140 inches
- Spacing (3″ × 12 gaps): 36 inches
- End allowance (2 × 10″): 20 inches
- Raw total: 140 + 36 + 20 = 196 inches = 16.3 feet
- Plus 12% sag factor: 196 × 1.12 = 220 inches ≈ 18.3 feet
Recommend purchasing a 20-foot clothesline to have comfortable working room.