This free cat window perch planner tells you what size window perch fits your window, from window width and cat weight, plus the safe load and how many suction cups it needs. It runs fully in your browser, so nothing you type is sent to a server, and you need no account and no sign-up to use it.
Many cat owners buy a perch that is too wide for the window, or too weak for the cat, and the perch ends up falling down. A perch should leave a small gap at each side so it fits flat, and it should hold at least twice the cat weight, because cats jump onto perches with force. Sizing it first saves a fall and a frightened cat.
Type the window width in centimetres and your cat weight in kilograms, then press the calculate button. The tool shows the perch width, the safe load, the number of suction cups, and the perch depth.
The result is a sizing guide, not a safety certificate. Always test the perch yourself before your cat uses it: press down firmly, check the cups hold for a day, and recheck them weekly. Replace cups that look flat, cracked, or yellow.
Example: a 90 cm window and a 4.5 kg cat suit a 70 cm perch that holds at least 9 kg, with 2 suction cups. A 50 cm window and an 8 kg cat suit a 40 cm perch that holds 16 kg, with 4 cups.
Clean the glass before fitting cups. Dust and grease are the main reason suction cups fail, and a clean window can double how long they hold.
Fit the perch low at first. Let a shy cat learn to use it near the floor, then move it up once the cat trusts it.
Add a soft mat on the perch. Cats stay longer on a warm, grippy surface, and the mat stops the cat sliding when it jumps up.
Common question: How much weight should a perch hold? At least twice the cat weight. A jumping cat lands with far more force than its standing weight.
Common question: Are sill-mounted perches better than suction cups? Sill mounts hold more weight and suit heavy cats, while suction cups suit renters and glass doors. Either works if it is rated above twice the cat weight.
Common question: Why does my cat ignore the perch? The perch may be wobbly, too high, too hot in direct sun, or facing a blank wall. Move it to a sunny window with birds or street life to watch.
Keep a simple notebook for a month. Write the numbers you used, the result, and what your cat did next. Did the cat sleep in the new bed, drink from the fountain, or walk calmly in the harness? That short record turns a vague feeling into clear evidence, and it makes the next adjustment much easier to judge.
A steady routine helps more than a perfect purchase. Feed at the same times, keep fresh water out, play at regular hours, and weigh your cat every few weeks. Cats settle well into routines, and a settled cat is easier to measure, easier to watch, and easier to keep healthy.
Finally, check the result against what you already own. If the new size is close to the old one, keep the old one. If it differs a lot, change in small steps and watch your cat for a week before you decide. Write both numbers down so you can compare them again later.
This tool is free to use as often as you like. Bookmark it, recheck the numbers when your cat grows, gains weight, or changes habits, and keep the daily routine steady. Small, steady habits matter far more for a cat than any single perfect number.