The assignment is due in two hours. Question 4 asks you to convert 3.5 miles to kilometers, find what percentage that is of your total 10km goal, then explain your answer in 200-250 words. You could solve all of this by hand—or you could verify your work instantly with the right tools and spend your energy on the explanation part that actually requires thinking.
Smart students don't avoid tools. They use tools for the mechanical parts so they can focus on the conceptual parts.
We built these calculators for ourselves, but students quickly became our biggest user group. This guide shows you how to use our tools for common academic scenarios—and more importantly, when not to use them so you actually learn.
Percentage Calculations
The Three Types You'll Encounter
Type 1: "What is X% of Y?"
- Example: What is 35% of 80?
- Formula: 80 × 0.35 = 28
- Use our Percentage Calculator
Type 2: "X is what percent of Y?"
- Example: 24 is what percent of 60?
- Formula: (24 ÷ 60) × 100 = 40%
- Use our Percentage Calculator
Type 3: "X is Y% of what number?"
- Example: 15 is 25% of what number?
- Formula: 15 ÷ 0.25 = 60
- Use our Percentage Calculator
Academic Applications
Test scores:
- You got 42 out of 50 questions right
- Calculation: (42 ÷ 50) × 100 = 84%
Grade weighting:
- Homework is 30% of your grade, you have 85% in homework
- Contribution: 0.30 × 85 = 25.5 points toward final grade
Percentage change:
- Population grew from 1,200 to 1,500
- Change: ((1,500 - 1,200) ÷ 1,200) × 100 = 25% increase
Unit Conversions
Length
Use our Unit Converter or Length Converter for:
| From | To | Multiply By |
|---|---|---|
| Inches | Centimeters | 2.54 |
| Feet | Meters | 0.3048 |
| Miles | Kilometers | 1.609 |
| Meters | Feet | 3.281 |
| Kilometers | Miles | 0.621 |
Science class example: Convert 5.2 miles to kilometers
- 5.2 × 1.609 = 8.37 km
Temperature
Celsius to Fahrenheit: (°C × 9/5) + 32 Fahrenheit to Celsius: (°F - 32) × 5/9
Chemistry example: Convert 25°C to Fahrenheit
- (25 × 1.8) + 32 = 77°F
Mass/Weight
| From | To | Multiply By |
|---|---|---|
| Pounds | Kilograms | 0.454 |
| Kilograms | Pounds | 2.205 |
| Ounces | Grams | 28.35 |
| Grams | Ounces | 0.035 |
Physics example: Convert 150 lbs to kilograms
- 150 × 0.454 = 68.1 kg
Volume
| From | To | Multiply By |
|---|---|---|
| Gallons | Liters | 3.785 |
| Liters | Gallons | 0.264 |
| Cups | Milliliters | 237 |
Word Count and Writing
Meeting Word Requirements
Use our Word Count tool to:
- Track progress toward word count requirements
- Check character counts for limited-length responses
- Estimate reading time for presentations
Common Academic Word Counts
| Assignment Type | Typical Length |
|---|---|
| Short answer | 50-150 words |
| Paragraph response | 150-300 words |
| Essay (short) | 500-800 words |
| Essay (standard) | 1,000-1,500 words |
| Research paper | 2,500-5,000 words |
| Thesis chapter | 5,000-10,000 words |
Writing Efficiency
If you're under the word count:
- Add examples
- Explain your reasoning more
- Address counterarguments
- Provide more evidence
If you're over the word count:
- Cut redundant phrases
- Remove filler words ("very," "really," "basically")
- Combine sentences
- Check if every paragraph earns its place
BMI and Health Calculations
For health class, PE, or biology, our BMI Calculator helps:
BMI Formula:
- Metric: weight (kg) ÷ height (m)²
- Imperial: (weight (lbs) × 703) ÷ height (in)²
Example: Calculate BMI for someone 5'10" (70 inches) and 165 lbs
- (165 × 703) ÷ (70 × 70) = 23.7
Understanding results:
- Under 18.5: Underweight
- 18.5-24.9: Normal
- 25-29.9: Overweight
- 30+: Obese
Important note: BMI is a screening tool, not a diagnosis. It doesn't account for muscle mass, bone density, or overall health.
Scientific Calculations
Significant Figures
When doing calculations, match the precision of your inputs:
- If your measurement is 5.2 meters, your answer shouldn't have 8 decimal places
- Report answers with appropriate significant figures
Unit Consistency
Before calculating, ensure all units match:
- Don't add meters and feet without converting first
- Don't mix grams and kilograms in the same formula
Checking Reasonableness
After any calculation, ask: "Does this answer make sense?"
- If you calculated that a car travels at 5,000 mph, something's wrong
- If your percentage is over 100% (when it shouldn't be), recheck
Study Techniques Using Tools
Practice Problems
- Work the problem by hand first
- Check your answer with the tool
- If wrong, identify where you made the error
- Redo similar problems until consistent
This builds understanding while ensuring accuracy.
Exam Preparation
- Learn the formulas (you won't have the tool in the exam)
- Use tools to generate practice problems with known answers
- Time yourself solving by hand
- Verify with tools after each practice session
Homework Strategy
For homework (where you might use tools):
- Read the problem completely
- Identify what's being asked
- Set up the problem structure
- Use tools for mechanical calculation
- Interpret and explain the result
The explaining and interpreting parts are what matter. The calculation is just arithmetic.
When NOT to Use Calculator Tools
During Learning
When you're first learning a concept, do it by hand. Tools are for verification, not replacement of understanding.
When Understanding Is Assessed
If the test is measuring whether you understand the process, showing only the answer suggests you don't.
For Simple Calculations
If you reach for a calculator for 10% of 100, you're losing mental math ability. Keep basic calculations sharp.
When It's Explicitly Prohibited
Follow assignment rules. If it says "show all work" or "no calculators," comply.
Quick Reference Card
Percentages
- X% of Y = Y × (X/100)
- X is what % of Y = (X/Y) × 100
- Increase/decrease = ((New-Old)/Old) × 100
Common Conversions
- 1 inch = 2.54 cm
- 1 mile = 1.609 km
- 1 kg = 2.205 lbs
- °F = (°C × 1.8) + 32
Word Count Estimates
- 1 page single-spaced ≈ 500 words
- 1 page double-spaced ≈ 250 words
- Average reading speed ≈ 200-250 words/minute
Circle/Sphere
- Circle area = πr²
- Circle circumference = 2πr
- Sphere volume = (4/3)πr³
- Sphere surface area = 4πr²
Conclusion
Tools don't make you worse at math—using tools instead of understanding makes you worse at math. Use them correctly and they make you faster and more accurate.
Our Percentage Calculator, Unit Converter, Word Count, and BMI Calculator are free, instant, and work on any device. Use them to check your work, not to avoid doing it.
The best students learn the concepts, practice the skills, and use tools strategically. That's not cheating—that's being smart about where to spend your mental energy.
Keep Reading
- Effective Study Learning Techniques - Study smarter
- Pomodoro Technique Guide - Focus during homework
- Everyday Calculations Quick Reference - More formula references
Related Tools
- Percentage Calculator - All percentage math
- Unit Converter - Any unit conversion
- Word Count - Track writing progress
- BMI Calculator - Health calculations