Weaving Calculators - Janet Dawson provides multiple online tools for sett and weaving calculations

Color

Brassard Cotton Color Numbers - all colors listed with RGB and hex numbers

Draft Color Editor - test different colors on any draft [available with subscription to Handweaving.net]

Weaving Color Mixer - terrific tool from Tien Chiu that illustrates how 2 colors [your choice] mix in various weaves

Design

Draft Editor plus hundreds of weaving drafts for 4 & 8 shafts - [available with subscription to Handweaving.net]

Random Stripe Generator - choose colors and width of stripes; intended for knitters but works for weaving

Inkle

Inkle Loom Pattern Generator - using a fill-in form you can try different patterns with lots of colours and see how it will look.

Kumihimo

Kumihimo Pattern Generator - design braids with any number of colors, see it in real time and then print out the instructions

Loom/Reed Adaptations

Reed Substitution Chart - figure out how to thread the reed when you don't have the most appropriate reed

Reed Substitution Tool - a simple form from Jane Stafford tells you what to thread with the reed you have

Treadle Reducer - a simple form that helps you reduce the number of treadles a pattern uses when you don't have enough

Sett

Average Sett Calculator - for mixed warps; Janet Dawson

Master Sett Chart - from Jane Stafford; lists suggested setts for cotton, linen, bambu, silk and wool.

Master Yarn Chart - from Interweave Press; lists many yarns with yards per pound and sett. Free but must register.

Weaving Calculators

Weaving Project Calculator - from Janet Dawson

Weaving Calculator - a helpful tool to calculate your warp and weft yardage, as well as your project costs.