Practical Guides

Measurements, methods and worked examples to help you use Jolbox calculators.

Golden dog sitting beside a stainless steel bowl of kibble and a measuring scoop on a kitchen floor.

Pets & Aquariums

How Many Calories Does a Dog Need Per Day?

Estimate dog calories with RER, compare puppy and adult factors, read food-label kcal, and subtract treats using checked feeding examples and clear limits.

Read guide →Gray tabby cat eating from a shallow ceramic bowl with a separate kibble scoop nearby.

Pets & Aquariums

How Many Calories Should a Cat Eat Per Day?

Calculate cat calorie estimates, compare kitten and adult needs, and work through wet-and-dry food portions without confusing cans, cups or safe weight management.

Read guide →Bowls of granulated sugar and flour with metal measuring cups and a digital kitchen scale on a wooden counter.

Food & Kitchen

How Many Cups Is 100 Grams? Ingredient Conversion Guide

Compare 100 grams of flour, sugar, butter, water, oats and cocoa in US cups using documented ingredient weights, with packing and cup-size limitations.

Read guide →Partly unrolled beige carpet in a bright room, with a tape measure and three carpet samples on the floor.

Home & Renovation

How Much Carpet Do I Need for a Room?

Measure room area in square feet and yards, compare carpet roll orientations, and separate waste, material pricing and installation in a checked US example.

Read guide →Crushed-stone driveway beside grass, with a measuring stake at the edge.

Home & Renovation

How Much Gravel Do I Need for a Driveway?

Calculate driveway gravel from length, width and depth, convert cubic yards to weight using bulk density, and allow for ordering without counting extra twice.

Read guide →River stones around planted shrubs beside a curved border and a small-gravel path with a resting garden rake.

Garden & Outdoor

How Much Gravel Do You Need for Landscaping?

Estimate decorative gravel for garden beds and paths, including irregular areas, depth choices, cubic yards and supplier-specific density without driveway assumptions.

Read guide →Stacks of plain coins beside a blank calendar and a blue circular target.

Family & Lifestyle

How Much Money Should I Save Each Month to Reach My Goal?

Work out monthly savings from your target, current balance and deposit dates, then compare a zero-interest plan with a hypothetical monthly-compounding example.

Read guide →Bark mulch around green garden plants, with the tree’s root flare and plant stems left clear.

Garden & Outdoor

How Much Mulch Do You Need for a Garden Bed?

Estimate garden-bed mulch from measured area and chosen depth, convert cubic feet to cubic yards, and compare rounded bag purchases with bulk volume.

Read guide →Paint roller and tray beside a partly painted interior wall and measuring tape.

Home & Renovation

How Much Paint Do You Need for a Room?

Estimate room paint from wall area, doors and windows, coats and label coverage. Follow a checked gallon calculation and separate touch-up allowance from rounding.

Read guide →Blue-and-cream quilt beside joined panels of plain backing cotton and sewing scissors.

Sewing & Quilting

How Much Quilt Backing Fabric Do I Need?

Estimate quilt backing yardage from quilt dimensions, overhang, usable fabric width and seam allowances, with a checked two-panel cutting example.

Read guide →Fresh produce and plain pantry groceries beside a blank-backed receipt and a calculator on a kitchen counter.

Family & Lifestyle

How Much Should You Budget for Groceries Each Month?

Build a monthly grocery budget from your own receipts, convert weekly spending with 52/12, and plan for household needs, waste and changing shopping schedules.

Read guide →Folded sweater and plain mug with blank tags, a calculator and blank-backed receipts on a tabletop.

Education & Everyday

How to Calculate a Discount When There Are Two Sales

Work out stacked percentage discounts, effective savings, coupon order and reverse prices with checked shopping examples and separate sales-tax assumptions.

Read guide →Timber forms outlining a rectangular slab on a gravel base with measuring tools nearby.

Home & Renovation

How to Calculate Concrete for a Slab

Calculate slab concrete in cubic feet and cubic yards from measured length, width and thickness, then compare an explicit allowance with ready-mix and bag yields.

Read guide →Household fan connected through a plug-in power meter at a wall socket.

Home & Renovation

How to Calculate Electricity Cost from Watts and Hours

Turn appliance watts and running hours into kWh and energy cost, with checked daily, monthly and yearly examples, standby power and electricity-bill limitations.

Read guide →Simple gable roof on a single-story house, viewed from ground level with its triangular end and shingled slope visible.

Home & Renovation

How to Calculate Roof Pitch: Rise, Run, and Degrees

Convert roof rise and horizontal run into X:12 pitch, angle, slope percentage and slope factor, with verified 4:12, 6:12 and 8:12 examples and safe measurement options.

Read guide →Jar of bubbly sourdough starter beside bowls of flour and water.

Food & Kitchen

How to Calculate Sourdough Hydration (Including Starter)

Calculate dough hydration by separating starter flour and water, then use baker’s percentages to check a recipe and adjust water for a target hydration.

Read guide →Overlapping red, green and blue light beside cyan, magenta, yellow and black paint swatches.

Photo & Printing

How to Convert RGB to CMYK for Printing

Learn the mathematical RGB-to-CMYK formula, check a worked color example, and understand why professional print conversion needs a printer-specific ICC profile.

Read guide →