Home, food & hobbies
729 everyday calculators for home, cooking and free time: recipes and servings, tips and shared bills, paint and flooring, pets, games and hobbies. Quick answers to the small questions of daily life, free in your browser.
Golden ratio font size calculator
Start from a 16 px body and every heading grows by the square root of phi, so heading 5 lands exactly on 16 times phi.
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Knitting gauge calculator
At 5.5 stitches and 7.5 rows per inch, a 20 by 24 inch piece needs 110 cast-on stitches and 180 rows.
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Modular type scale generator
From a 16 px base with a 1.25 ratio, five steps give 16, 20, 25, 31.25, 39.0625 and 48.828125. Pick three numbers and get a whole hierarchy of type sizes…
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Musical interval calculator
From C up to G is 7 semitones, a perfect fifth: enter two note names, with or without octave numbers, and get the distance in semitones, the short label and the…
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Note frequency calculator
A4 sounds at 440 Hz and is MIDI note 69: enter a note name and an octave, change the reference A if your ensemble tunes elsewhere, and get the exact frequency…
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NPF rule calculator
At f/2.8 with a 24 mm lens and 5.9 µm pixels, stars on the celestial equator stay sharp for under three seconds: enter aperture, focal length, pixel pitch and…
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Poker outs and odds calculator
With 9 outs and 47 unseen cards, the next card completes a flush draw exactly 9 times in 47: enter your outs and the unseen cards to get the exact chance on the…
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Print size & DPI calculator
A 3000 × 2000 pixel photo at 300 DPI prints 10 inches wide, or 25.4 cm: enter the pixel size and either a DPI or the print size you want, in inches, centimetres…
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Reading time estimator
A 1200-word article read at 200 words per minute takes 6 minutes: enter the word count and a realistic reading speed to get the time in minutes, hours and…
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Epoxy resin mix calculator
A 2:1 epoxy for a 100 ml mold splits into two thirds resin and one third hardener: enter the total amount and the ratio printed on the bottle, by volume or by…
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Musical scale generator
C major comes out as C D E F G A B with the pattern whole, whole, half, whole, whole, whole, half: pick a root such as F sharp or B flat and a scale type to get…
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Music transposition calculator
Move C up 2 semitones and you get D. Type a note or chord such as F#m7 or C/E, choose how many half steps to shift, and get the new chord with its quality and…
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Yarn weight substitution calculator
A pattern needing 1200 yards takes 6 skeins of 220 yards but 7 of 180, because 1200 divided by 180 is six and two thirds.
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Air conditioner BTU calculator
A 250 sq ft room with an 8-foot ceiling, average sun and two people needs about 5000 BTU per hour.
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Concrete block calculator
263 blocks cover a 20 m² wall when each face measures 0.4 by 0.2 m and you allow 5 percent for cuts and breakage.
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Carpet calculator
A 5 by 4 m room with a 4 m roll needs one 5 m strip, or 5.5 linear metres with 10 percent waste, instead of two strips totalling 8 m.
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Concrete column calculator
Four round columns 0.4 m across and 3 m tall take about one and a half cubic metres of concrete: pi times the radius squared times the height, times the number…
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Concrete footing calculator
Four pad footings of 2.4 × 0.6 × 0.3 m hold 1.728 m³ of concrete, 0.432 m³ each: length times width times depth, times the number of identical pads.
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Concrete slab calculator
A 4 × 3 m shed pad, 10 cm thick, needs 1.2 m³ of concrete, exactly 80 bags at the default bag size.
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Crown molding calculator
A 48 ft room with 8 ft sticks and 10% waste needs 7 sticks of crown molding, covering 52.8 ft with 3.2 ft left over.
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Deck board calculator
A 24 m² deck with 0.14 × 3.6 m boards, 5 mm gaps and 10% waste needs 51 boards. Each board is counted with its gap, the waste is added on top, and the result is…
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Fence post calculator
A 100-foot run with posts every 8 feet needs 13 sections, 14 posts and 26 rails at 2 rails per section, because neighbouring sections share a post.
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Lawn fertilizer calculator
A 5,000-square-foot lawn fed 1 pound of nitrogen per 1,000 square feet from a 20% nitrogen bag needs 25 pounds of product.
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Floor tile calculator
A 20 m² room laid with 0.6 m tiles and 10% waste needs 62 tiles, which is 7 boxes of 10. Enter room area, tile size, waste and tiles per box to buy whole boxes…
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Gravel calculator
Covering 50 m² with gravel 0.1 m deep takes 5 m³, which at a bulk density of 1,600 kg/m³ weighs 8,000 kg.
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Heater BTU calculator
A 2,000 cubic foot room with good insulation and a 30 °F temperature rise needs 60,000 BTU per hour.
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Insulation R-value calculator
3.5 inches of fiberglass batt at R-3.14 per inch plus half an inch of gypsum board at R-0.9 add up to a wall of R-11.44.
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Laminate flooring calculator
A 20 m² room with laminate packs that cover 2.2 m² each and the default 10% waste needs 22 m² of planks, so you buy 10 packs.
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Mortar calculator
500 bricks at 0.001 cubic metres of mortar each need 0.5 m³ of mortar, which is 42 whole bags of a typical 0.012 m³ mix.
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Paver calculator
A 20 m² patio laid with 0.6 m square pavers and 10% waste needs 62 pieces. Enter the area, the paver size and your waste allowance, and the count is always…
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Pool chlorine dosage calculator
Raising 10,000 US gallons from 1 to 3 ppm with 10% liquid bleach takes 25.6 fl oz, or 1.668 lb of product.
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Swimming pool volume calculator
A 10 by 5 m rectangular pool with an average depth of 1.5 m holds 75 m³, or 75,000 litres. Choose rectangular, round or oval, enter the sizes and get litres and…
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Roof pitch calculator
Measure 6 of rise over 12 of run and you have a 6/12 pitch, a 50% slope and a rafter multiplier of about 1.118.
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Roofing shingles calculator
A 2,000 sq ft roof plan with a 1.118 pitch factor has 2,236 sq ft of real surface, which means 23 squares and 68 bundles at 33.3 sq ft per bundle.
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Sand calculator
12 m² of patio bedding laid 0.1 m deep is 1.2 m³ of sand, and at 1,600 kg/m³ that weighs 1,920 kg.
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Staircase step calculator
A 2800 mm floor-to-floor rise with a 180 mm target riser becomes 16 equal risers of exactly 175 mm and 15 treads, with tread depth and a total run of 4375 mm…
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Topsoil calculator
1,000 sq ft of lawn topped with 2 inches of soil takes just over 6 cubic yards, or a little under 5 cubic metres.
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Wall stud calculator
A 120-inch wall framed at 16 inches on center takes 9 studs, counting both corners, and one door adds 2 more for 11 in total.
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Wall tile calculator
A 12 m² wall covered in 0.3 by 0.6 m tiles with 10% waste needs 74 tiles, which is 8 boxes of 10 with 6 left over.
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Wallpaper rolls calculator
A 5 m wide, 2.4 m high wall with 10 m by 0.53 m rolls and a 0.64 m pattern repeat needs 4 rolls: 10 strips cut to 2.56 m, 3 per roll. Area alone would say 3.
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Water tank volume calculator
A 2 by 1 by 1.5 meter tank filled to 0.75 meters holds 1500 of its 3000 liters. Pick a box, upright cylinder or horizontal cylinder, enter inside dimensions and…
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Buy one get one discount calculator
Take five items on a buy-one-get-one deal and you pay for three, two come at no charge and the real discount is 40 %.
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Recipe cost per serving calculator
Flour, eggs, milk and butter costing 6.7 in all, cut into 4 servings, come to 1.675 per plate. Enter what each ingredient cost for the batch and how many it…
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Shared expense splitter
Receipts of 45.5, 30 and 24.5 shared by three people, one of them counted double, come to 25, 25 and 50.
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Quit a habit savings calculator
Skip a habit that costs 5.5 a day for 30 days and you keep 165. Enter what it costs on a typical day and how long you plan to stay off it, from a trial month to…
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Markup to margin converter
An 80 cost with a 25% markup sells for 100, which is only a 20% margin. Enter the cost and either the markup or the margin to get the selling price, the profit…
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Overtime pay calculator
A rate of 20 with 40 regular hours and 5 overtime hours at 1.5 times gives 800 regular, 150 overtime and 950 gross.
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Price per 100g calculator
A 500 g pack at 1.5 and a 2000 g bag at 3 cost 0.3 and 0.15 per 100 g, so the big bag wins even with the higher sticker.
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Rule of 114 and 144 calculator
At 8% a year, savings take about 14.25 years to triple and 18 years to quadruple: 114 and 144 divided by the rate.
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Salary to hourly converter
A salary of 52,000 at 40 hours a week for 52 weeks works out to exactly 25 an hour and 1,000 a week.
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Sales tax calculator
A purchase of 100 at 8.25% sales tax carries 8.25 in tax and a total of 108.25 at checkout. Type the pre-tax price and the rate as a percentage, and every step…
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Savings goal time calculator
With 10,000 as the goal, 2,500 already saved and 500 set aside each month, you reach the target in exactly 15 months, or one year and three months.
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Subscription annual cost calculator
A 15.99 monthly streaming plan, 99.99 a year for cloud storage and 12 a month for news come to 36.32 a month and 435.87 a year.
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Tip and split calculator
A bill of 86.4 with an 18% tip split four ways comes to a 15.55 tip, a 101.95 total and 25.49 per person.
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Unit price comparison calculator
A 32-ounce jar at 5.99 beats a 16-ounce jar at 3.49 once both prices are divided by size: it costs less per ounce.
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Attic insulation depth calculator
Reaching R-49 with blown cellulose rated 3.2 per inch takes 15.3125 inches. Enter your target, the product's R-value per inch from its data sheet and any…
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Baseboard heater sizing calculator
A 150 sq ft room in a moderate climate needs 1500 watts, which is 6 feet of standard 250 W-per-foot baseboard heater.
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Block wall calculator
A 20 m² wall in 0.4 by 0.2 m blocks with 5 percent waste takes 263 blocks and 27 bags of mortar. Enter the wall area, the face size printed on the pallet and…
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Brick mortar bag calculator
500 bricks at 40 bricks per bag need 13 bags of mortar mix, with room left for 20 more bricks. Enter your brick takeoff and the coverage printed on the bag, add…
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Ceiling fan size calculator
A 200 sq ft room calls for a 48-inch ceiling fan, within a 44 to 50 inch range, and a single fan is enough.
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