Answers to common questions
Short, direct answers to 1906 questions people search for about money, health, engineering, code, design and more. Each answer comes from one of our in-depth guides and links to it, and to the free tool that does the work.
Engineering questions
- Where does the 1.44 in the 555 timer formula come from?
- What engineering tasks can AI draft safely?
- How long does it take to clear a room at 5 air changes per hour?
- Should asphalt tonnage use loose or compacted thickness?
- How do I find a battery's Peukert exponent?
- Where does 5wL⁴/384EI come from?
Development questions
- How do I find which .gitignore rule is ignoring a file?
- What is the difference between a 301 and a 308 redirect?
- How does Base64 encoding work?
- What is the difference between js-beautify and Prettier?
- What is the difference between a trigger and a root cause in a postmortem?
- What naming convention does Python use?
Productivity questions
- Why not calculate age by dividing days by 365.25?
- What tasks can AI help executive assistants with?
- Why do timers run slower in a background tab?
- How do I convert a gas mark to Fahrenheit?
- What is inside a DOCX file?
- What mistakes do engineering manager candidates make in interviews?
Design questions
- How do fancy text generators work?
- What is a triadic colour scheme?
- Why does the order of CSS transform functions matter?
- What is the depth of field of a 50mm lens at f/8?
- What is one stop of light in photography?
- Is a lens's angle of view quoted horizontally or diagonally?
Finance questions
- When do I become eligible for 401(k) catch-up contributions?
- Why do bond prices fall when interest rates rise?
- What is averaging up in stocks?
- How do I convert a lease money factor to APR?
- What is the ex-dividend date?
- Is it better to prepay a loan early or late?
Health questions
- What are the 18 HIPAA Safe Harbor identifiers?
- What is the difference between ACC/AHA and ESH blood pressure categories?
- What is the Mifflin-St Jeor equation?
- How do I measure body fat with a tape measure?
- Why is eGFR reported per 1.73 m²?
- What is the physiological sigh?
Security questions
- How do I create an .htpasswd file?
- What is a padding oracle attack?
- How do I read a bcrypt hash?
- Should I blur or pixelate text in a screenshot?
- What is the difference between a checksum and a digital signature?
- What is a birthday attack on a hash function?
Business questions
- Does CAN-SPAM apply to B2B sales emails?
- What is a GTIN?
- What is units of production depreciation?
- What is FMEA?
- What is force field analysis?
- What is the formula for a freelance hourly rate?
Home & DIY questions
- How long is a ramp for 3 steps?
- Is cellulose or fiberglass better R-value per inch?
- Why is the baluster spacing rule 4 inches?
- What is the difference between cutting crown molding nested and flat?
- How much waste should I add for deck boards?
- How much tile waste should I allow?
Science questions
- Why does ice float on water?
- What is the terminal velocity of a skydiver?
- How do I calculate how long an EV takes to charge?
- How do you find the pH of a strong base?
- What does CO₂e mean?
- Where does the kinetic energy formula ½mv² come from?
Math questions
- What is Heron's formula for the area of a triangle?
- Why is anything to the power of zero equal to 1?
- How do I calculate average cost per share?
- What is the difference between accuracy and precision?
- What are the product, quotient and power rules for logarithms?
- What are the three elementary row operations?
Statistics questions
- Why is the standard survey sample size 385?
- What is the difference between a paired and an independent t-test?
- What is Anscombe's quartet?
- When should I use the median instead of the mean?
- How do I standardise a normal variable?
- What are the assumptions of a one-way ANOVA?
Tech questions
- What is the difference between SFT and DPO?
- What is an MCP server?
- How do I block AI training crawlers but still appear in AI search?
- How much does prompt caching save on LLM API costs?
- What is the difference between local and remote MCP servers?
- What are the parts of a good AI prompt?
Data questions
- What is the difference between Avro and Protobuf encoding?
- How do I remove duplicate lines and keep the order?
- What is inside an xlsx file?
- What is a TSV file?
- What is a Parquet file?
- Is a bar chart or a pie chart better for comparing values?
Education questions
- What does FIGlet stand for?
- What do I need on my final exam to get the grade I want?
- What day of the week was July 4, 1776?
- How do I calculate the ISO week number by hand?
- Who invented Morse code?
- What is the Flesch-Kincaid grade level formula?
Startups questions
- How do I choose between several startup ideas?
- What is a Foundation Sprint?
- How is a Lean Canvas different from a traditional business plan?
- What happens to a co-founder's equity if they leave early?
- What are unit economics for a startup?
- Who coined the term minimum viable product?
Fun questions
- What is the best strategy for 2048?
- Is a coin flip really 50/50?
- How does a 3D globe wrap a flat map onto a sphere?
- What was Sam Loyd's 14-15 puzzle?
- What frequency is middle C?
- Why does the online fortune cookie stay the same all day?