Small, sharp online tools
TinkerBrook is a growing collection of free calculators, converters and generators. Each one does a single job well: open it, get your answer, get back to what you were doing. No sign-up, no downloads, and everything works on your phone.
The tools
Everything below is live — and more are on the bench.
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Kitchen
Sourdough hydration calculator
True dough hydration including your starter — or pick a target and get exact gram weights.
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Kitchen
Air fryer conversion calculator
Turn any oven time and temperature into air fryer settings. °F/°C, both directions.
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Kitchen
Air fryer cooking times
One chart with temps and times for 60 everyday foods, each with a full guide.
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Video
Video bitrate calculator
The right bitrate for your resolution, frame rate and platform, plus file size ⇄ bitrate.
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Gaming
Minecraft circle generator
Pixel-perfect circle and oval blueprints with live block counts.
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EV
EV charging cost calculator
What a charge really costs with your rate, plus a vs-gas comparison.
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Math
Fraction calculator
Add, subtract, multiply and divide fractions and mixed numbers — with the steps shown.
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Health
Steps to miles calculator
Steps to real distance from your height and step length — plus the reverse and a chart.
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Writing
Reading time calculator
Words to minutes for silent reading and speech — paste text or a word count.
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Hobby
Aquarium volume calculator
Tank gallons and liters for 4 shapes, with water weight and a size chart.
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Craft
Epoxy resin calculator
Resin for any pour in oz and ml — split into Part A and B for your mix ratio.
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Craft
Board foot calculator
Lumber board feet with 4/4 quarter buttons, quantity and cost math.
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Health
One rep max calculator
Estimated 1RM from any set — Epley and Brzycki, with your %1RM table.
How TinkerBrook works
Every tool ships together with a plain-English guide that explains the formula behind it, so you can trust the number you get — or do the math yourself next time. Tools are built to stay fast: static pages, nothing to install, and no tracking beyond basic ads and cookie-free anonymous traffic stats.