Math dashboard
Everyday math, instantly.
School math, real-life math, and the math your phone calculator gets almost-right — all in one place, with the steps shown. CalcBold Math tools render the formula in numbers, the simplified step, and the final answer (so students actually learn) and pair the result with a plain-English AI explanation that catches the classic traps: +20%/-20% is not original, percentage-of-change uses the starting value, stacked discounts don't add.
- Live tools
22
- Searches / mo
77M+
- Top calc SV
25M+/month
- Sources
3+
Most-searched
Top math tools
- #1
Percentage Calculator
One calculator for all five classic percentage problems — X% of Y, X is what % of Y, X increased/decreased by Y%, and % change from one value to another. Full working shown.
25M+/month
- #2
Unit Converter
Six measurement domains in one tool. Length (m/km/mi/ft/in), weight (kg/lb/oz/st), volume (l/gal/cup/oz), temperature (C/F/K/R), area (m²/ft²/acres/ha), and time (s/min/hr/day/wk/mo/yr).
10M+/month
- #3
Fraction Calculator
Add, subtract, multiply, or divide two fractions. Result shown in simplest form, mixed-number form, and decimal — with the step-by-step working that produced it.
8M+/month
Playground
Try Percentage Calculator
Live, fully interactive — same engine as the standalone calc.
All tools
Every math calculator
Everyday Math
13 tools- PercentageHot
Percentage Calculator
One calculator for all five classic percentage problems — X% of Y, X is what % of Y, X increased/decreased by Y%, and % change from one value to another. Full working shown.
25M+/month - FractionHot
Fraction Calculator
Add, subtract, multiply, or divide two fractions. Result shown in simplest form, mixed-number form, and decimal — with the step-by-step working that produced it.
8M+/month - DiscountHot
Discount Calculator
Drop the original price and discount percent — get the sale price, dollar savings, and effective price ratio. Reverse mode finds the discount % from original + sale prices.
4M+/month - TipHot
Tip Calculator
Restaurant tip math, end-to-end. Drop the bill amount, pick the tip percent, optionally add tax and split across diners — get the per-person total in one tap.
3M+/month - VAT / TaxHot
VAT / Sales Tax Calculator
Drop a price and rate — get the tax-included total OR reverse from a tax-included total to the pre-tax price. 20+ country presets (UK 20%, EU avg, India GST 5/12/18/28%, AU/NZ GST, Japan, Singapore, UAE, US average) plus a custom-rate option.
3M+/month - RatioHot
Ratio Calculator
Three operations on ratios. Simplify any A:B to its simplest form. Find an equivalent value (A:B ↔ X:?). Or split a total in a given ratio. GCD-based simplification with full step-by-step working.
3M+/month - AverageHot
Average / Mean Calculator
Drop a list of numbers (commas or spaces) — get the mean, median, mode, range, min/max, and population standard deviation. Up to 10,000 values supported.
2M+/month - AreaNew
Area Calculator
Compute the area of eight common shapes from their dimensions — and get the perimeter or circumference where the shape supports it. Step-by-step working shown for every result.
200K+/month - Standard DeviationNew
Standard Deviation Calculator
Paste a dataset (CSV, whitespace, or one per line) and get the population σ or sample s standard deviation, variance, mean, range, and coefficient of variation. NIST-style math; works for up to 10,000 values.
165K/month · $1.20 CPC - VolumeNew
Volume Calculator
Compute the volume of eight common 3D shapes from their dimensions — and get the surface area where the shape supports it. Step-by-step working shown for every result.
150K+/month - P-ValueNew
P-Value Calculator
Drop a test statistic and pick the test type (Z, T, Chi-square, or F). Get the exact p-value plus significance verdicts at α=0.05 and α=0.01. One- or two-tailed for Z and T; right-tail for Chi and F. NIST-style numerical methods.
90.5K/month · $1.65 CPC - Z-ScoreNew
Z-Score Calculator
Drop a value, mean, and SD — get the z-score, percentile, and how rare the observation is (tail probability). Or go the other way: enter a z-score, get the matching raw value. Standard normal math, NIST-style.
49.5K/month · $1.30 CPC - Aspect RatioNew
Aspect Ratio Calculator
Solve any missing dimension from a width and height — or scale to a target ratio. GCD-reduces to lowest integer form and snaps to the standard formats (16:9, 9:16, 4:3, 21:9, 1:1, 3:2, 5:4) with industry-standard ±2% tolerance.
14.8K/month · $7.95 CPC
School & Grading
4 tools- Word CounterHot
Word Counter
Paste any text and get word count, character count (with and without spaces), sentence and paragraph counts, average word length, and accurate reading/speaking time estimates.
5M+/month - GPANew
GPA Calculator
Compute your semester or cumulative GPA across any number of courses. US 4.0 scale and Indian / Korean 4.5 scale supported. Each course weighted by its credit hours, with quality-points breakdown.
4M+/month - GradeHot
Grade Calculator
Two modes. (1) Given current grade + final exam weight + target overall, compute the score you NEED on the final. (2) Given current + final score + weight, compute your overall course grade and US letter.
3M+/month - Final ExamNew
Final Exam Grade Calculator
Type your current grade, the final exam's weight, and the letter grade you want. The calculator updates live and tells you exactly what score you need on your final.
500K+/month
Conversions
2 tools- Unit ConverterHot
Unit Converter
Six measurement domains in one tool. Length (m/km/mi/ft/in), weight (kg/lb/oz/st), volume (l/gal/cup/oz), temperature (C/F/K/R), area (m²/ft²/acres/ha), and time (s/min/hr/day/wk/mo/yr).
10M+/month - Shoe SizeNew
Shoe Size Converter
Convert across all 6 standard systems (US Men, US Women, UK, EU, JP/Mondopoint, CM) plus brand-fit notes for Nike, Adidas, Asics — the small-print most converters skip.
1.5M+/month
Advanced & Notation
3 tools- RNGHot
Random Number Generator
Pick a range, pick how many, pick whether duplicates are allowed — get cryptographic-grade random integers backed by `crypto.getRandomValues` whenever the runtime exposes it. Works for raffles, lotteries, gaming, sampling, and fairness-critical draws.
2M+/month - Sci NotationHot
Scientific Notation Calculator
Drop any number — standard (150,000,000) or scientific (1.5e8 / 1.5×10⁸) — and get all three forms back: standard with thousands separators, scientific notation a × 10ᵇ, and engineering notation (powers of 3 matching SI prefixes). Order of magnitude included.
1.5M+/month - RomanHot
Roman Numeral Converter
Drop a Roman numeral (MMXXVI, IVL, MCMLXIV) or an integer 1–3,999 — get the other form. Subtractive notation enforced (IV not IIII). Worked breakdown shows each glyph's contribution.
800K+/month
Sources we cite
Where math numbers come from
Standard arithmetic conventions · IEEE 754 · BIPM SI units
Frequently Asked Questions
The most common questions we get about this calculator — each answer is kept under 60 words so you can scan.
Are these math calculators good enough for homework?
Yes — every result includes the working in 3 lines (formula in numbers, simplified step, final answer), so a student can copy the method as well as the answer. The AI insight then explains why the answer is what it is — useful for closing the conceptual gap that makes percentages and fractions so easy to get wrong.Does the Percentage Calculator handle all five problem types?
Yes — the single page covers: X% of Y · X is what % of Y · increase Y by X% · decrease Y by X% · % change from old to new. The mode select swaps the input labels and units, so the form self-documents. The +20%/-20% ≠ original trap is called out explicitly in the page's SEO content.How do you handle edge cases — division by zero, negative percentages, etc.?
Every formula returns a tone-tagged error rather than NaN/Infinity. Zero divisor (e.g., 'X is what % of 0') returns a clean error message. Negative percentages are accepted where meaningful (e.g., decrease) and flagged where not (e.g., percentage-of-Y where Y is positive but the result would be negative).Is there a unit converter or a fraction calculator yet?
Percentage Calculator is the first Math tool live (Day 10). Fraction, tip, GPA, grade, unit converter, word counter, ratio, discount, and VAT/sales-tax follow in Phase 2 (Weeks 3–5). Each one uses the same 3-line working layout so the surface stays consistent.
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