Guides
Clear, expert-reviewed content that explains the concepts behind our calculators — formulas, worked examples, reference tables and comparisons, each linked to the tools that put them into practice.
2036 articles
Expert-reviewed deep dives that explain the concepts behind our calculators.
Get your pet's portions and habitat right — how to work out how much to feed a dog or cat, judge body condition, and measure an aquarium's true volume for safe, healthy stocking.
Buy the right amount and avoid costly mistakes — how to work out fabric yardage, match knitting gauge, estimate yarn, and measure quilt binding for any project, with the pro's margins.
The numbers that sharpen your photography — the exposure triangle, exposure value, depth of field and hyperfocal distance, crop factor, flash guide numbers and print size.
The calculations behind music production — delay times locked to the beat, note frequencies, how decibels fall with distance, sample rate and bit depth, and sizing audio files.
The physics that governs rockets, satellites and stars — gravity, escape velocity, orbital speed, surface gravity, the scale of the cosmos and the strange mathematics of black holes.
Plan a productive garden with confidence — how much soil to buy, how far apart to space plants and trees, how much seed and fertiliser you need, and the watering to keep it all thriving.
The quick calculations that save you money every day — splitting a bill with a tip, adding and removing tax, checking a discount is real, comparing unit prices and estimating your bills.
The numbers behind the weather and a thriving garden — how wind chill and heat index work, what dew point tells you, when each becomes dangerous, and how to water and harvest rain.
Turn marks into percentages, percentages into GPA and CGPA, and work out exactly what you need on a final exam — the maths every student should know.
The core mechanics formulas every student needs — velocity, acceleration, the equations of motion, force, momentum, work, energy and power — explained plainly with worked examples.
Cut through property hype with the numbers that matter — NOI, cap rate, rental yield, cash-on-cash return and DSCR — plus the costs beginners forget, so you can judge a deal like an investor.
A practical guide to home solar — understanding your usage, how many panels you need, sizing the inverter and battery, net metering, the payback period and the carbon you save.
Make sense of the numbers on the scoreboard — batting average, strike rate, bowling economy and required run rate — and what they really tell you about a game.
Two simple methods to size your life cover — income replacement and the DIME approach — so your family is protected without over-paying for premiums.
The everyday conversions everyone needs — between metric and imperial length, weight, temperature, speed, volume and area — with the key factors, mental tricks and the mistakes to avoid.
The everyday electrical maths every hobbyist and electrician uses — Ohm's law, power, sizing a resistor, combining resistors, and the basics of current, voltage and safe wiring.
Beyond the sticker price — depreciation, financing, fuel, insurance and maintenance — plus how electric cars compare on running cost, range and charging time, with a total-cost view.
Why great bakers weigh, not scoop — baker's percentages, dough hydration, ingredient ratios, oven temperatures and how to scale any recipe up or down with confidence.
The essential area, perimeter and volume formulas for circles, rectangles, triangles, spheres and cylinders — what they mean, how to handle composite shapes, and how to keep units straight.
Stop guessing and over-buying — how to estimate paint, tiles, concrete, flooring and bricks for a home project, measure tricky rooms, and add the wastage allowance the pros always include.
The handful of marketing numbers that actually matter — conversion rate, CPC, ROAS, CAC, lifetime value and churn — what they mean, how they fit together, and which to ignore.
Master every kind of percentage problem — finding a percentage of a number, percentage change, increases and decreases, working backwards, and the traps that catch people out — with clear examples.
The core statistics everyone should know — mean, median, mode, range and standard deviation — what each tells you, when averages mislead, and how the normal distribution ties them together.
Margin and markup are easy to confuse but mean very different things — and mixing them up can quietly destroy your pricing. Here's how each works, how to convert between them, and how to price for profit.
Showing 24 of 47 — find the rest from the Related guides section on each calculator page.
Step-by-step formulas and worked examples for calculating each metric by hand.
Learn how to calculate R-Value Insulation — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Goals Per Game — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Revenue Per Visitor — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Property Registration Charges — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate CAC Payback Period — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Points Percentage — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Cost Per Install (CPI) — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Net Rental Yield — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Average Revenue Per User (ARPU) — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Premium Allocation Charge — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Tea for a Crowd — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Harmonic Mean of Three Numbers — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Thunder Distance — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Free Fall Velocity — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Power from Torque and RPM — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Battery Series Voltage — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Brick Wall Cost — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Cost Per Day of Membership — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Gutter Length — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Square Side from Diagonal — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Pizza Slices Per Person — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Fuel Efficiency Improvement — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Surface to Volume Ratio of a Sphere — the formula explained step by step, with worked examples and a free calculator to check your answer.
Learn how to calculate Hours to Work Days — the formula explained step by step, with worked examples and a free calculator to check your answer.
Showing 24 of 998 — find the rest from the Related guides section on each calculator page.
At-a-glance tables of exact, engine-computed values across common scenarios.
Reference table of patio cost for Patio Cost across a range of patio area values — exact, engine-computed figures you can read off at a glance.
Reference table of points percentage for Points Percentage across a range of points won values — exact, engine-computed figures you can read off at a glance.
Reference table of cost per install for Cost Per Install (CPI) across a range of total ad spend values — exact, engine-computed figures you can read off at a glance.
Reference table of net rental yield for Net Rental Yield across a range of annual rent values — exact, engine-computed figures you can read off at a glance.
Reference table of average revenue per user for Average Revenue Per User (ARPU) across a range of total revenue values — exact, engine-computed figures you can read off at a glance.
Reference table of allocation charge for Premium Allocation Charge across a range of premium paid values — exact, engine-computed figures you can read off at a glance.
Reference table of total wallpaper cost for Wallpaper Cost across a range of number of rolls values — exact, engine-computed figures you can read off at a glance.
Reference table of downpipes needed for Downpipe Count across a range of roof area values — exact, engine-computed figures you can read off at a glance.
Reference table of tread life remaining for Tyre Life Remaining across a range of current tread depth values — exact, engine-computed figures you can read off at a glance.
Reference table of r-value for R-Value Insulation across a range of material thickness values — exact, engine-computed figures you can read off at a glance.
Reference table of goals per game for Goals Per Game across a range of total goals values — exact, engine-computed figures you can read off at a glance.
Reference table of revenue per visitor for Revenue Per Visitor across a range of total revenue values — exact, engine-computed figures you can read off at a glance.
Reference table of registration charges for Property Registration Charges across a range of property price values — exact, engine-computed figures you can read off at a glance.
Reference table of payback period for CAC Payback Period across a range of customer acquisition cost values — exact, engine-computed figures you can read off at a glance.
Reference table of guttering needed (perimeter) for Gutter Length across a range of roof length values — exact, engine-computed figures you can read off at a glance.
Reference table of efficiency improvement for Fuel Efficiency Improvement across a range of old fuel efficiency values — exact, engine-computed figures you can read off at a glance.
Reference table of work days for Hours to Work Days across a range of total hours values — exact, engine-computed figures you can read off at a glance.
Reference table of plants needed for Hedge Plants across a range of hedge length values — exact, engine-computed figures you can read off at a glance.
Reference table of weighted sum for Weighted Sum across a range of value 1 values — exact, engine-computed figures you can read off at a glance.
Reference table of paper needed (with overlap) for Gift Wrap Paper across a range of box length values — exact, engine-computed figures you can read off at a glance.
Reference table of assists per game for Assists Per Game across a range of total assists values — exact, engine-computed figures you can read off at a glance.
Reference table of cost per engagement for Cost Per Engagement across a range of total spend values — exact, engine-computed figures you can read off at a glance.
Reference table of distance fallen for Free Fall Distance across a range of fall time values — exact, engine-computed figures you can read off at a glance.
Reference table of future rent for Rent Escalation across a range of current rent values — exact, engine-computed figures you can read off at a glance.
Showing 24 of 970 — find the rest from the Related guides section on each calculator page.
Side-by-side breakdowns to help you choose between two options.
SIP (12%) vs RD (6.5%) compared side by side — the differences, the numbers, and which to choose.
Mutual fund (12%) vs FD (7%) compared side by side — the differences, the numbers, and which to choose.
Home loan (8.5%) vs Personal loan (14%) compared side by side — the differences, the numbers, and which to choose.
Car loan (9.5%) vs Personal loan (14%) compared side by side — the differences, the numbers, and which to choose.
SIP (₹5,000/mo) vs Lump sum (₹6,00,000) compared side by side — the differences, the numbers, and which to choose.
Simple interest vs Compound interest compared side by side — the differences, the numbers, and which to choose.
FD (₹3,00,000) vs RD (₹5,000/mo) compared side by side — the differences, the numbers, and which to choose.
PPF vs Equity SIP compared side by side — the differences, the numbers, and which to choose.
Plain-English answers to “what is a good / average …” questions.
As a rough rule, a net profit margin around 10% is considered average, 20% or more is good, and under 5% is low — but it varies widely by industry. Margin is the share of revenue left as profit after costs.
For most e-commerce websites, a conversion rate of 2–3% is average and anything above about 5% is considered good. Rates vary widely by industry, traffic source and what counts as a 'conversion', so always compare against your own benchmark.
For rental property, a capitalisation (cap) rate of roughly 5–10% is generally considered good, with many investors targeting around 8%. A higher cap rate means more income relative to price — but often more risk. What's 'good' depends on the market and property type.
For long-term stock-market investing, an average annual return of about 7–10% (after inflation, roughly 7%) is widely considered good. For a one-off project, a positive ROI that beats safer alternatives is the benchmark. 'Good' always depends on the risk taken and the time involved.
A gross rental yield of around 3–5% is typical for residential property in many Indian cities, and anything above roughly 5% is generally considered good. Yield is the annual rent expressed as a percentage of the property's value, so a higher figure means stronger rental income relative to price.
A DSCR of 1.25 or higher is generally considered good by lenders — it means the income available is at least 1.25 times the debt payments. A DSCR below 1.0 means income does not cover the debt, while 1.5 and above is seen as strong.
A ROAS of around 4:1 — ₹4 in revenue for every ₹1 spent on ads — is a common benchmark for a healthy, profitable campaign. What is 'good' depends on your margins: low-margin businesses need a higher ROAS to profit, while high-margin ones can succeed with less.
A good click-through rate (CTR) depends on the channel: around 2% or higher is solid for Google Search ads, display ads often sit near 0.5%, and email campaigns average 2–5%. CTR is the share of people who click after seeing your ad, link or email.
A widely used benchmark is to save at least 20% of your income, as in the 50/30/20 budget. Saving 20% or more is good, 10–20% is a solid start, and below 10% leaves little buffer. Higher savers reach financial goals — and early retirement — much faster.
A debt-to-income (DTI) ratio of 36% or below is generally considered good, and many lenders prefer your total EMIs to stay under 40–43% of your gross monthly income. The lower your DTI, the more comfortably you can take on and repay debt.
In India, a CIBIL credit score of 750 or above is generally considered good and gives you the best chance of loan and credit-card approval at favourable interest rates. Scores run from 300 to 900, and most lenders treat anything from 750 upward as low-risk.
For men, a healthy body fat percentage is roughly 10–20%, and for women about 18–28%, with women naturally carrying more essential fat. Athletes are often lower, while levels well above these ranges raise health risks.
For most adults, a healthy BMI is between 18.5 and 24.9. A BMI below 18.5 is classed as underweight, 25 to 29.9 as overweight, and 30 or above as obese. BMI is a quick screening tool, not a diagnosis — it does not distinguish muscle from fat.