Fesaer is a single, fast toolbox for the small jobs you hit every day — a quick percentage, a unit conversion, a strong password, a summary of a long paragraph. Everything runs instantly in your browser.
Everyday math, done in one click.
Check your body mass index from height and weight, with the standard WHO categories.
Open tool →Find a percentage, work out increases, or reverse a percentage change.
Open tool →Exact age in years, months and days from any birth date.
Open tool →Monthly instalment, total interest and payoff breakdown for any loan.
Open tool →Move between units without the mental math.
Length, weight and volume — metric to imperial and back.
Open tool →Celsius, Fahrenheit and Kelvin, converted instantly.
Open tool →HEX, RGB and HSL — convert and preview any color.
Open tool →Switch text between UPPER, lower, Title and Sentence case.
Open tool →Create what you need, then copy it out.
Strong, random passwords with full control over length and characters.
Open tool →Turn any link or text into a downloadable QR code.
Open tool →Placeholder text by word, sentence or paragraph count.
Open tool →Pick random numbers in any range, with or without repeats.
Open tool →Lightweight writing helpers, no account needed.
Condense a long paragraph down to its key sentences.
Open tool →Turn a topic into a set of ready-to-use social hashtags.
Open tool →A fresh batch of post and video ideas for any niche.
Open tool →Live word, character, sentence and reading-time counts.
Open tool →Every calculation happens on your device. Nothing you type is uploaded anywhere.
Open a tool and use it. There's nothing to sign up for and nothing behind a login.
Formulas follow standard, documented methods — the same ones used in textbooks and finance tools.