Guides
The longer answers behind the calculators: what to measure, which rules apply, and where every number comes from.
Money & work
- Debt Avalanche vs Snowball: Which Pays Off Debt Faster?Debt avalanche vs snowball, worked through on three cards: how each method orders payments, what each costs in interest, and when the snowball is worth it.
- How to Calculate Overtime Pay: Federal and California RulesHow overtime pay is worked out: time and a half over 40 hours, why bonuses raise your overtime rate, and California's daily and double-time rules, with examples.
- Markup vs Margin: The Difference and How to ConvertMarkup vs margin explained with real numbers: the formulas, how to convert one to the other, a pricing example, and the mix-up that quietly costs small sellers.
- Salary to Hourly: How to Convert Your Pay the Right WayConvert an annual salary to an hourly wage: why 2,080 hours is the standard, how unpaid time off and long weeks change it, and what exempt vs non-exempt means.
- Self-Employment Tax 2026: Rates and Quarterly Due Dates2026 self-employment tax explained: 15.3% on 92.35% of profit, the $184,500 Social Security cap, the deductible half, and Form 1040-ES quarterly due dates.
Home & DIY
- How Much Tile Do I Need? Herringbone vs Straight LayHow much tile to buy for a herringbone floor versus a straight lay: waste allowances, plank tile, box rounding and spares, with a worked bathroom example.
- How Many Bags of Concrete per Fence Post? Charts and MathA 4x4 in a 10 in hole 3 ft deep takes about 3.4 bags of 50 lb fast-setting concrete. Per-post charts by hole size, both Quikrete bag types, and a 100 ft example.
- How Much Paint Do I Need for a Room? Coats, Primer and CansHow much paint you need for a room: wall area, one coat or two, when primer is worth it, and whether to buy gallons or a 5-gallon pail, with a worked example.
- Stair Stringer Layout That Passes Inspection (2021 IRC)Lay out a stair stringer that meets the 2021 IRC: 7¾ in max risers, 10 in min treads, 3/8 in tolerance. A worked deck stair and the mistakes that fail inspection.
- How Much Mulch Do I Need? Mulch vs Gravel, Bags vs BulkHow much mulch you need by depth and bed size, how gravel compares, and the simple sum that tells you when bulk delivery beats bags. Worked examples included.
Auto
- How Car Loan Interest Works: Rates, APR and Loan TermHow car loan interest is calculated month by month, why APR is not the same as the rate, and what a 48 vs 72-month term really costs, with a worked $30,000 example.
- IRS Mileage Rate 2026: 72.5¢, Then 76¢ From July 1The 2026 IRS mileage rates: 72.5 cents to June 30 and 76 cents from July 1, plus medical, moving and charity rates, how reimbursement works and what to record.
- Road Trip Gas Cost: How to Work It Out and Split ItWork out the gas cost of a road trip from miles, MPG and pump price, then split it fairly. Worked round-trip example using October 2026 EIA prices by region.
- How to Edit a PDF on iPhone, Android, Mac or ChromebookWhat the built-in PDF apps on iPhone, Android, Mac and Chromebook can and can't do, and how to change the words in a PDF in your browser without uploading it.
- How to Edit Text in a PDF Without Acrobat (and Keep the Font)Change words in a PDF without Adobe Acrobat: rewrite a line in a matching font, find and replace across pages, and know what Word conversion and scans can't do.
- How to Edit a PDF Without Uploading It (and How to Check)Most online PDF editors send your file to their servers. Here is how in-browser editing differs, how to check it yourself in DevTools, and which files to guard.
- How to Fill Out a PDF Form for Free, Fillable or NotHow to fill out any PDF form free: type into fillable fields, fill a flat form with text, ticks and dates, sign it, and what to do when a form says Please wait.
- Is White-Out Enough to Hide Text in a PDF? How to Redact SafelyWhy a white or black box over PDF text usually leaves the words in the file, what real redaction removes, how to check your copy, and what our Whiteout tool deletes.
- How to Compress a PDF Under 2 MB Without Wrecking the TextWhy PDFs get big, how to compress a PDF under 2 MB or any upload limit while keeping text sharp and searchable, and what to do when it still won't fit.
- How to Merge PDF Files Without Uploading ThemHow to merge PDF files into one, in the right order, without uploading them: mixed page sizes, locked files, and what happens to bookmarks and form fields.
- How to Sign a PDF: E-Signature vs Digital SignatureHow to sign a PDF by drawing, typing or uploading your signature, what US law (ESIGN and UETA) says about e-signatures, and when ink or a certificate is needed.
- How to Make a Scanned PDF Searchable With Free OCRHow to make a scanned PDF searchable and copyable with OCR: what OCR adds to the file, scan settings that help, languages, and how accurate to expect it to be.
- How to Password Protect a PDF (and What It Really Stops)How to password protect a PDF with AES-256: open password vs permissions password, what print and copy restrictions really do, and how to remove a password you know.
Images & photos
- How to Compress an Image to Under 100 KB (and Keep It Sharp)How to compress a photo to under 100 KB for an upload form: resize first, then lower quality, pick JPG, PNG or WebP, and why 100 KB can mean two numbers.
- HEIC to JPG: Why iPhone Photos Get Rejected and the FixWhat HEIC is, why Windows PCs and upload forms reject iPhone photos, how to make your iPhone shoot JPG, and how to convert HEIC to JPG without uploading.
Pets
- Dog Ate Grapes, Raisins or Xylitol? What to Do Right NowIf your dog ate grapes, raisins or anything with xylitol, call a vet or poison line now. Who to call, what to have ready, and what happens over the next 72 hours.
- Dog Years to Human Years: Why the ×7 Rule Is WrongA 1-year-old dog is closer to 15 in human years than 7. See the 2020 DNA formula, the size chart by weight and what your dog's age means for vet care.
- How Much to Feed My Dog: Use the Calories on the BagWork out how much to feed your dog from the calorie statement on the bag: the RER and MER formulas, a worked example in cups and grams, and when to ask your vet.
Daily life
- 2027 US federal holidays (with observed dates)All 11 US federal holidays for 2027 with the weekday off for each, why three of them move to a Friday or Monday, and why New Year's Day 2028 lands on December 31.
- Age-appropriate chores for kids, from 2 to 17Chores kids can do at every age from 2 to 17, drawn from pediatrician lists, plus how to teach a new job, how many to give, the allowance question and mowing safety.
- A Beginner 3-Day Gym Plan You Can PrintA beginner 3-day full-body gym plan with sets, reps and rest from ACSM guidance, cardio to hit 150 minutes a week, how to pick weights, and a printable version.
- Calories in Fruit: A Full List by PortionCalories and fiber in 35 fruits by the portion you actually eat, from USDA FoodData Central, plus per-100 g values and how dried fruit and juice compare.
- High-Protein Foods Ranked by CaloriesCommon high-protein foods ranked by grams of protein per 100 calories, from USDA FoodData Central, with the calories it takes to get 30 g from each.
- How Big a Calorie Deficit Is Safe? Rates, Floors and a Worked PlanA safe calorie deficit for most adults is about 500 to 750 calories a day. What the CDC and the obesity guideline say, the calorie floors, and a worked example.
- How Long to Cook a Turkey per Pound (and Why 165 °F Matters)Turkey roasting times at 325 °F from the USDA chart, what they work out to per pound, and why the bird is done at 165 °F on a thermometer, not when the timer ends.
- How Long to Thaw a Turkey: Fridge vs Cold WaterHow long a frozen turkey takes to thaw in the fridge or in cold water, from the USDA chart, plus the day to start for Thanksgiving 2026 at every weight.
- How Many Calories Should I Eat a Day? Ranges and Your Own NumberHow many calories you need a day: the federal estimates by age, sex and activity, how to work out your own number with Mifflin-St Jeor, and two worked examples.
- How Many Steps Are in a Mile? By Height, and How to Measure YoursHow many steps are in a mile: roughly 2,000 to 2,600 by height, why the height rule is only an estimate, and how to measure your own step length.
- How Much Protein Do You Need a Day? From the RDA to Active AdultsHow much protein you need a day: the 0.8 g/kg RDA, the new 1.2 to 1.6 g/kg Dietary Guidelines target, ranges for active and older adults, and a sample day in food.
- How to build a habit tracker that you actually keepHow to set up a habit tracker you stick with: pick a small habit, tie it to a cue, track it daily and plan for about two months, based on what habit research found.
- How Your Due Date Is Calculated (and Why It Can Change)How your due date is calculated: 280 days from your last period, the IVF and conception versions, and when an early ultrasound changes the date, per ACOG guidance.
- Is BMI Accurate? What It Can and Can't Tell YouIs BMI accurate? What the CDC says BMI is good for, where it misleads (muscle, age, sex, ethnicity), and what to measure alongside it, with worked examples.
- Mifflin-St Jeor vs Harris-Benedict vs Katch-McArdle: Which to UseMifflin-St Jeor, Harris-Benedict and Katch-McArdle compared: where each BMR formula comes from, how far apart they land for three real examples, and which to trust.
- Running Pace Charts for 5K, 10K, Half and Full MarathonPace charts for 5K, 10K, half marathon and marathon finish times, per mile and per kilometer, worked out from pace = time ÷ distance, plus treadmill speeds.
- Time blocking: how to plan your day on paperHow to time block a day on paper: put fixed events in first, give your top priorities real slots, add buffer, and redraw the plan when the day goes sideways.
- Weighted vs Unweighted GPA: What's the Difference?Unweighted GPA treats every class the same on a 4.0 scale; weighted GPA adds points for honors and AP. How each is worked out, and why colleges recalculate.
- What Do I Need on My Final? The Formula, ExplainedThe formula for the score you need on your final exam, worked through with real numbers, plus a lookup table and what to do when the answer is over 100%.
- What Time Should I Go to Bed? Sleep Cycles ExplainedWork out a bedtime from your wake-up time, the hours of sleep the CDC recommends for your age, and roughly 90-minute sleep cycles, with an honest note on their limits.