Quick answers to everyday math.
Free calculators for sellers, home projects, pets, hobbies and money. No sign-up, and they work on your phone.
🏷️ Reselling & Marketplace Fees
Know exactly what you'll take home before you list. Fee and profit calculators for eBay, Poshmark, Mercari and Etsy.
Amazon Fee CalculatorCalculate Amazon referral fees by category, the $0.99 or $39.99 plan cost, FBA and media closing fees, and see your profit, margin and ROI per sale.Depop Fee CalculatorCalculate Depop's 3.3% + $0.45 payment processing fee and 12% Boosted Listings fee for US sellers, plus your payout and profit after costs.eBay Fee CalculatorCalculate eBay final value fees (13.6% + $0.40), your payout and real profit after item cost, shipping and promoted listing fees.Etsy Fee CalculatorCalculate Etsy's listing, 6.5% transaction, 3% + $0.25 processing and Offsite Ads fees, plus your payout and profit after materials and shipping.Facebook Marketplace Fee CalculatorCalculate the Facebook Marketplace selling fee on shipped orders (10%, $0.80 minimum), your payout and profit, and compare it with a fee-free local sale.Flip Profit CalculatorCalculate profit, ROI, margin and profit per hour on any flip, with eBay, Poshmark, Mercari and Etsy fee presets, and find the most you should pay for an item.Markup & MarginFind a selling price from cost plus markup or a target profit margin, or enter cost and price to get both. Includes a markup-to-margin conversion table.Mercari Fee CalculatorCalculate Mercari's 10% selling fee, your payout and real profit after item cost, shipping and the optional $3 Instant Pay fee. Updated for 2026.Poshmark Fee CalculatorCalculate Poshmark's fee ($2.95 under $15, 20% at $15 and up), your earnings and real profit after item cost and any shipping discount you cover.StockX Fee CalculatorCalculate your StockX payout after the 7%–9% transaction fee by seller level, 3% payment processing, the $5 minimum and $5 shipping fee, plus your profit.TikTok Shop Fee CalculatorCalculate TikTok Shop's referral fee, affiliate creator commission, payout and profit per order. Includes the new-seller 3% rate and a custom rate option.Whatnot Fee CalculatorCalculate Whatnot's 8% commission and 2.9% + $0.30 processing fee, your payout and profit per sale. Supports custom rates for the new volume tiers.
🏠 Home Project Calculators
Figure out how much paint, mulch, gravel, concrete or flooring you need, and what it will cost, before you go to the store.
Concrete CalculatorCalculate cubic yards of concrete for a slab, footing or round post hole, the number of 40, 60 or 80 lb premix bags, and the ready-mix cost with waste.Deck CalculatorEstimate how many deck boards to buy for a deck of any size, with board width, gap and length, plus linear feet, joist count, screws and decking cost.Drywall CalculatorEstimate drywall sheets for a room's walls and ceiling, minus doors and windows, plus screws, joint compound, tape and total material cost.Electricity CostFind what any appliance costs to run per day, month and year from its wattage, hours of use and your electricity rate, with typical watts for common devices.Fence CalculatorEstimate posts, rails, pickets or privacy boards and bags of concrete for a wood fence from its length, height, post spacing and gates, plus total cost.Flooring CalculatorWork out how many square feet and boxes of laminate, vinyl plank, hardwood or tile to buy, with waste for straight, diagonal or herringbone layouts.Grass Seed CalculatorFind how many pounds and bags of grass seed your lawn needs for a new lawn or overseeding, by grass type and area, with cost and starter fertilizer.Gravel CalculatorEstimate how much gravel you need in cubic yards, tons and 0.5 cu ft bags for pea gravel, crushed stone, river rock or road base, plus the total cost.Mulch CalculatorCalculate how much mulch you need in cubic yards and 2 or 3 cubic foot bags from your bed size and depth, and compare bagged versus bulk mulch cost.Paint CalculatorFind how many gallons of paint a room needs from its size, doors, windows and number of coats, with an optional ceiling and a total paint cost estimate.Raised Bed SoilFind how much soil fills your raised beds in cubic feet and yards, split into Mel's Mix or 60/30/10 components, with bag counts, cost and extra for settling.Roofing CalculatorEstimate roof area, squares and shingle bundles from your house size and pitch, plus underlayment rolls, drip edge, ridge cap and an installed cost range.Tile CalculatorWork out how many tiles and boxes to buy for a floor or wall, with grout joint width, layout waste, a grout estimate in pounds and total tile cost.Wallpaper CalculatorCount the wallpaper rolls a room needs using the strip method, with pattern repeat, trim allowance, doors and windows, roll size and total cost.
🐾 Pet Calculators
Feeding amounts, age conversions and tank stocking for dogs, cats and fish.
Aquarium Stocking CalculatorCheck how stocked your freshwater tank is. Pick common fish and quantities, add tank size and filter rating, and get a stocking level plus school-size warnings.Cat Age CalculatorConvert your cat's age to human years using the AAHA/AAFP chart (15 at one, 24 at two, then 4 per year) and see which veterinary life stage your cat is in.Cat Food CalculatorFind how many calories your cat needs daily and how many cans of wet food and cups of dry food that is, with any wet and dry mix, from weight and life stage.Cat Pregnancy CalculatorEnter your cat's mating date to get her kitten due date, the normal 61 to 72 day birthing window, how far along she is and a timeline of pregnancy signs.Dog Age CalculatorConvert your dog's age to human years by size (small to giant) or with the UCSD DNA-methylation formula, and see which life stage your dog is in.Chocolate Toxicity CalculatorEstimate how dangerous the chocolate your dog ate may be, using the dog's weight, chocolate type and amount. Always call your vet or pet poison control too.Dog Food CalculatorWork out how many calories and cups of food your dog needs per day from weight and life stage, plus cups per meal and how long a bag will last.Dog Pregnancy CalculatorFind your dog's due date from the breeding, ovulation or LH surge date, plus how far along she is and a week-by-week timeline of scans, prep and whelping.Dog Water CalculatorFind out how much water your dog should drink a day in ounces, cups and ml, adjusted for weight, activity, hot weather and wet or dry food, plus warning signs.Pet Cost CalculatorEstimate what a dog or cat really costs per year, per month, in the first year and over its lifetime, with editable food, vet, insurance and care costs.Puppy Weight CalculatorEstimate how big your puppy will get from its age in weeks, current weight and breed size, with how much of its adult size it has reached and when growth stops.
🧵 Hobby & Craft Calculators
3D printing costs, fabric yardage, lumber board feet and coffee brew ratios.
3D Print Cost CalculatorWork out what a 3D print really costs: filament, electricity, printer wear and failed prints, plus a suggested sale price with your markup.Baker's Percentage CalculatorTurn baker's percentages into gram weights for bread, sourdough and pizza. Start from flour weight or from dough balls, with starter and effective hydration.Blanket Yarn CalculatorEstimate how much yarn a knit or crochet blanket needs by size and yarn weight, from baby to king, plus skeins to buy with a safety margin and total cost.Board Foot CalculatorCalculate board feet for hardwood and lumber from thickness, width and length, add a waste allowance, and see the total cost at your price per board foot.Candle Wax CalculatorFind how much wax and fragrance oil to melt for a batch of container candles, from the water your jar holds, plus cost per candle and a retail price.Coffee Ratio CalculatorFind how much coffee to use for pour-over, French press, AeroPress, drip, cold brew or espresso, in grams and tablespoons, from your water or number of cups.Cross Stitch Fabric CalculatorFind the finished size of a cross stitch design and how much Aida or evenweave to cut, from the stitch count, fabric count and margin, in inches and cm.Epoxy Resin CalculatorWork out how much epoxy resin you need for a table top, coasters or a river table, split into part A and part B, with kits to buy and total cost.Fabric Yardage CalculatorEstimate how many yards of fabric to buy from your cut pieces, fabric width, pattern repeat and shrinkage allowance, rounded up to the nearest 1/8 yard.Knitting Gauge CalculatorTurn your swatch gauge into stitches to cast on and rows to knit, rounded to a pattern multiple, or see how a different gauge changes a pattern's size.Photo Print Size CalculatorSee how big you can print a photo from its pixel dimensions at 300, 240 or 150 DPI, plus the effective DPI and crop for 4×6 up to 24×36 prints.Quilt CalculatorWork out quilt backing yardage and panel layout, binding strips and yardage, and the right pre-cut batting size from your quilt top width and length.
💵 Money & Side Hustle Calculators
Take-home pay from side gigs, freelance rates and lease-versus-buy decisions.
Compound Interest CalculatorSee how savings grow with compound interest. Enter a deposit, monthly contribution, rate and years to get your final balance and a year-by-year growth table.Credit Card Payoff CalculatorSee how many months it takes to pay off a credit card, total interest, and how much you save versus minimum payments, or find the payment for a target date.Debt Payoff CalculatorCompare debt snowball and avalanche for up to 5 debts. See your debt-free date, total interest for each method, interest saved and the order debts get paid.Emergency Fund CalculatorAdd up your essential monthly expenses to find your emergency fund target for 3 to 12 months, the gap from your savings, and how long it will take to get there.Freelance Rate CalculatorWork out the hourly, day and monthly rate you need as a freelancer to hit your income goal after taxes, expenses, time off and unbillable hours.Gig Driver Earnings CalculatorFind your real hourly pay driving for DoorDash, Uber, Lyft or Instacart after gas, car wear and taxes, plus per-mile earnings and net pay per week and year.Hourly to Salary CalculatorConvert an hourly wage to annual, monthly, biweekly, weekly and daily pay, or a salary to an hourly rate, with overtime, unpaid time off and rough take-home.Lease vs Buy CalculatorCompare the true cost of leasing versus financing a car over the same period, including down payment, sales tax, mileage overage fees and resale equity.Rent Affordability CalculatorFind the most rent you can afford with the 30% rule, 50/30/20 budget, 40x landlord rule or a debt-to-income check, plus the income needed for any rent.Savings Goal CalculatorFind how much to save each month, paycheck or week to reach a savings goal by your target date, with interest from a high-yield savings account included.Side Hustle Tax CalculatorEstimate 2026 self-employment tax, federal and state income tax on side gig income, your real take-home, and how much to set aside for quarterly payments.