UD5 Toolkit
Duct Tape Sheet Calculator – Online Length for Wallet or Purse
Enter wallet size and get the exact length of duct tape strips needed to build a sheet. DIY crafting.
Online Calculators - Math & More
99+ toolsDrum Shell Fundamental Note Calculator – Online Bearing Edge
Enter drum diameter, depth, and material to find the shell's approximate fundamental note. For tuning reference.
Pond Algaecide Dose Calculator – Online Gallons & Product %
Enter pond volume and product concentration to determine safe ml or teaspoon of algaecide.
DIY Electrolyte Powder Calculator – Online Sodium Potassium Glucose Ratio
Create your own oral rehydration solution by mixing salt, potassium, and sugar to WHO formula. Convert to teaspoon amounts.
Shoelace Length Calculator – Online Eyelet Pairs & Pattern
Enter number of eyelet pairs and lacing style to find the correct shoelace length in inches/cm. Never buy too short.
Coffee Extraction Estimator – Online TDS & Yield from Refractometer
If you have a refractometer reading, enter TDS and brew weight to get extraction yield. Dial in your pour‑over.
Jerky Marinade Ratio Calculator – Online Soy, Worcestershire, Cure
Scale a jerky marinade recipe based on meat weight. Includes optional cure #1 calculation for safety.
Hole Saw Speed & Feed Calculator – Online Diameter & Material
Enter hole saw diameter and material to find the recommended RPM and feed pressure. Prevent burning and kickback.
Spray Paint Distance & Coverage Calculator – Online Even Coat Tool
Enter nozzle type and surface area to get optimal spray distance, sweep speed, and estimated cans needed. Prevent runs and drips.
Candlepin Bowling Score Calculator – Online Small Ball Scoring
Keep score for candlepin bowling with its unique rules. No strike carries automatic strikes. For New England enthusiasts.
Tea Leaf Expansion Calculator – Online Pot Size & Leaf Weight
Enter pot volume and tea type to find the right amount of dry leaf considering expansion. Avoid overflowing.
Koi Pond Stocking Calculator – Online Gallons per Fish
Enter pond dimensions and filtration type to estimate safe number of adult koi. Prevent overcrowding.
Erg Stroke Rate & Split Predictor – Online Concept2 Pace Chart
Enter distance and time to get your 500m split. Also predicts how a change in stroke rate affects power output.
Soda Ash Soak Calculator – Online Tie‑Dye Prep Ratio
Calculate water and soda ash needed to pre‑soak fabric for tie‑dye. Achieve vibrant, long‑lasting colors.
Safe Room Size Calculator – Online Occupancy & Ventilation Check
Enter number of people and desired duration to estimate the minimum square footage and ventilation CFM for a residential storm shelter.
Chicken Feed Ration Calculator – Online Layer, Broiler, Chick
Mix your own feed by entering grain percentages and see the resulting crude protein. Formulate a balanced diet for your flock.
Wine Must Adjuster – Online Sugar, Acid & Tannin Calculator
Enter your must volume and current Brix, TA, and pH to calculate additions of sugar, acid blend, or tannin. Standard winemaking formulas.
Soap Superfat & Lye Purity Adjuster – Online Cold Process Calc
Adjust your lye amount based on lye purity (KOH/NaOH) and desired superfat percentage. Provides safety check for handmade soap recipes.
Time‑Lapse Interval Calculator – Online Shoot Duration & Playback Length
Plan your time‑lapse by entering desired clip length, fps, and event duration to find the shooting interval and total frames needed. Avoid under‑ or over‑shooting.
Bolt Torque to Tension Estimator – Online Simple Calculator
Enter bolt diameter and applied torque to estimate clamping force. Use standard friction factors.
Resin Casting Volume Calculator – Online Mold & Part A/B
Enter mold dimensions or water weight to get total resin needed, including Part A and B.
Spring Constant & Elastic Energy Calculator – Online Hooke's Law
Enter spring constant and displacement to find force and stored energy. Visual compression.
Leftover Paint Coverage Calculator – Online Touch‑Up Planning
Enter the amount of leftover paint and see how many square feet it still covers. Plan touch-ups.
Freelance Day Rate Calculator – Online Project Cost Estimator
Based on desired annual income and billable days, calculate your minimum day rate. Don't undercharge.
Moving Truck Size Calculator – Online Bedrooms to Cubic Feet
Enter number of bedrooms and large items to estimate the truck size you need. Avoid multiple trips. Simple local estimator.
IBU Calculator for Homebrew – Online Hop Schedule Tool
Enter hop additions with time and alpha acid to estimate International Bitterness Units. Adjust recipe.
Road Trip Playlist Time Calculator – Online Music for Miles
Enter total drive time or playlist length to figure out how many songs you need. Convert time to estimated tracks.
Crochet Hat Sizing Guide – Online Measure & Increase
Enter head circumference to get crown diameter and length. Perfect fit top‑down hats.
Aquarium Fishless Cycle Ammonia Calculator – Online Dose
Calculate how much pure ammonia to add to reach 4ppm for a fishless cycle. Safe start guide.
Water Leak Cost Calculator – Online Drip to Gallon Waste
Select drip speed or running toilet and see gallons wasted per day and annual cost. Fix leaks!
Screen Time Reward Calculator – Online Chores = Minutes
Enter completed chores/reading minutes to calculate earned screen time. Customizable rates. Local tracking.
Series & Parallel Resistor Network Solver
Build a combination resistor network by adding series/parallel groups and get total resistance. Visual circuit.
Viewport Unit Calculator – Online vw vh vmin vmax to PX
Enter a CSS value in vw/vh and see the actual pixel size at current viewport. Dynamic resize demo.
Salary Negotiation Anchor Calculator – Online First Offer Strategy
Based on your target salary, calculates a high anchor number to improve negotiation outcome. Psychological tactic.
Credit Card Utilization Calculator – Online Ratio & Score Effect
Enter total balance and limit to see utilization percentage. See how it affects credit score bands.
Auto Loan Calculator – Online Monthly Payment Estimator
Enter vehicle price, down payment, rate, term to compute monthly payment and total interest paid.
Rent vs Buy Breakeven Calculator – Online Simple Comparison
Compare renting to buying a home by entering price, rent, interest, and years. See which saves more. Simplified model.
Paper Towel Consumption Estimator – Online Weekly Roll Use
Track how many rolls you use per month. Input sheet count to find cost per sheet. Reduce waste.
Toilet Paper Stock Calculator – Online How Long Will It Last?
Enter rolls remaining and household size to estimate weeks of supply. A humorous yet practical aid.
Portable Generator Sizing – Online Wattage Estimator
Add appliances with running and starting watts to estimate needed generator capacity. Prevent overload.
Emergency Water Storage Calculator – Online Gallons per Person
Calculate how many gallons of water to store based on household size and days. Preparedness aid.
Rice Water Ratio Calculator – Online White Brown Jasmine Basmati
Select rice type and number of cups to get exact water measurement. Perfect fluffy rice every time.
Popcorn Yield Calculator – Online Kernels to Popped Volume
Enter amount of kernels and see estimated popped volume. Plan movie night snacks perfectly.
Rubber Band Ball Calculator – Online Estimate Bands Needed
Enter current ball size and target to find approx rubber bands required. Fun and satisfying.
Macrame Cord Length Estimator – Online Project Calculator
Calculate total cord needed for a macrame plant hanger or wall hanging based on size and knot density.
Pom‑Pom Yarn Calculator – Online How Many Wraps for Size
Enter desired pom-pom diameter to estimate yards needed and number of wraps. Quick craft math.
Sore Throat Remedy Mix Calculator – Online Salt/Gargle Ratios
Calculate salt to warm water ratio for effective gargle. Also ginger and honey tea prep. Simple first aid.
Aquarium Additive Doser – Online ml per Gallon Calculator
Enter tank volume and recommended dose to find exact ml or capfuls needed. Avoid overdosing fish.
Liquid Fertilizer Dilution Calculator – Online Mix Ratio
Calculate how much liquid fertilizer concentrate to add per gallon of water based on desired N concentration.
Close‑Up Lens Diopter Calculator – Online Magnification Estimate
Convert diopter strength to approximate magnification and working distance for macro photography.
Depth of Field Calculator – Online Near/Far Focus Limit
Input camera sensor, focal length, aperture, distance to get hyperfocal distance and DoF range. Visual chart.
Golden Hour & Blue Hour Calculator – Online Sunrise/Sunset Light
Enter a date and location (or use GPS) to see exact golden hour and blue hour times for perfect natural light.
Overtime Pay Calculator – Online Time‑and‑a‑Half Estimator
Enter regular hours, hourly rate, and overtime hours to calculate total weekly pay. Follows standard 1.5x rule.
Child Support Estimator – Online Simple State Guideline Calculator
Approximate monthly child support obligation based on both parents incomes and number of children. Uses simplified model for educational reference. Not legal advice.
Yarn Substitution Tool – Online Match Gauge & Yardage
When a yarn is discontinued, find equivalent alternatives by matching weight and gauge. Local reference.
Pickling Brine Calculator – Online Vinegar Water Salt Ratio
Create the perfect brine for refrigerator pickles. Adjust ratios by weight. Quick and safe recipe tool.
Compost Ratio Calculator – Online Brown/Green Balance Tool
Adjust material types (leaves, grass) to achieve the ideal 30:1 C:N ratio. Improve compost bin performance. Local only.
RV Battery Drain Calculator – Online Estimate Off‑Grid Duration
Enter appliance loads and battery capacity to estimate how long your RV can run without recharging. Local simulation.
Tiny House Cost Estimator – Online DIY Build Budget Tool
Breakdown of expected costs (materials, appliances, etc.) for a tiny house. Adjust percentages or enter custom. Local calculation.
Picture Hanging Height Calculator – Online Eye‑Level Guide
Find the ideal height to hang art based on wall and furniture dimensions. Follow gallery standard 57‑inch center rule.