About

About Consumable Calculators

One question, answered for your situation: how often should I replace this?

Why this exists

Filters, blades, bags, and batteries all need replacing on some schedule, but the guidance is scattered across box inserts, manuals, and manufacturer FAQs, and it rarely accounts for how you actually use the thing. A pitcher filter rated for 40 gallons doesn't last "two months" in a house of five. These calculators turn the official ratings into a schedule for your household.

How the estimates work

Each calculator starts from a baseline interval taken from manufacturer or safety agency guidance, then adjusts it for the factors that change real-world wear: household size, water hardness, pets, usage, and so on. The result is a range, and the page shows which of your answers moved it and by how much.

Pages list their sources and the date they were last reviewed.
Where official guidance sets a hard limit, such as the U.S. Fire Administration's yearly smoke alarm battery change, the calculator never recommends going past it.
An estimate is a starting point. If performance drops, a filter smells, or a blade is damaged, replace it sooner and use that as your new baseline.

How the site makes money

Results link to matching products on Amazon. As an Amazon Associate, the site earns from qualifying purchases, at no extra cost to you. Links are chosen to match what the calculator told you to buy, and the estimates don't depend on what earns more. There are no ads, accounts, or cookies set by this site.

Who builds it

Consumable Calculators is built and maintained by Mark Nelson, a software engineer who kept looking up "how often do I replace…" and getting vague blog posts instead of answers. It's part of Tiny Tools, a small collection of independent, single-purpose products.

Corrections and suggestions