Eri Tech Studio
/ Free tools
Free Tools & Calculators
Small, fast, free calculators from the apps we build. No signup, nothing gated.
Baking
from The Bake Log
Sourdough Hydration Calculator
Flour, water and starter in — true hydration % out, or work backwards from a target.
Baker's Percentage Calculator
Scale any bread formula from flour weight or target dough weight.
Starter Feeding Ratio Calculator
1:1:1, 1:2:2, 1:5:5 — exact feed amounts and expected peak times.
Dough Temperature Calculator
Hit a target dough temperature — the water temp you need, from flour and room.
Coffee
from Kohii
Coffee Ratio Calculator
Coffee-to-water ratios for V60, Chemex, AeroPress, French press and more.
Espresso Ratio Calculator
Dose, yield, ratio — enter any two and solve the third.
Coffee Freshness Calculator
Roast date in, peak window out — for espresso and filter.
Wine
from Cellar Book
Wine Drink Window Calculator
Style and vintage in — ageing, ready, at peak or fading out.
Wine Cellar Value Calculator
Count by tier — total value, average per bottle, replacement figure.
Plants
from Leaflet
Plant Watering Calculator
Watering intervals by species, season and light.
Travel
from The Travel Binder
Packing List Generator
Trip length, climate and style in — a categorised list with quantities out.
Japan Trip Cost Calculator
Nights and travel style in — a line-by-line budget, per person and per day.
Consumer rights
from Warranty Box
UK Return Rights Checker
Which legal return or refund window you're in, from the purchase date.