A Reference Library for Everyday Decisions

Free online calculators and utility tools for finance, math, health, productivity, and life decisions — curated, organized, and always free. No account required.

Open the Catalog
I.

Catalog Index

A ·

Finance & Investment

24 tools
Compound Interest Capital Gains High-Yield Savings
B ·

Business & Revenue

20 tools
Business Exit Valuation Cash Flow Forecast Break-Even
C ·

Health & Wellness

16 tools
Health Insurance Deductible Child BMI Calories Burned
D ·

Math & Conversion

12 tools
Currency Conversion Baking Temperature Flexbox Layout
E ·

Marketing & Advertising

14 tools
Google Ads ROAS Conversion Rate Influencer ROI
F ·

Shipping & Trade

15 tools
International Shipping LTL Freight Class Import Duty & Tax
G ·

Home & Daily Living

18 tools
Family Budget Housing Cost Ratio Cooking Time
H ·

Gaming & Entertainment

10 tools
Gacha Pity Counter Magic Damage Drop Rate
II.

Curated Selection

01
FinanceEditor's Pick

Compound Interest Calculator

"The single most important calculator on the site — see how your money grows, or doesn't, over decades."

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02
InvestmentEditor's Pick

Discounted Cash Flow

"If you're evaluating any investment, start here. The math behind every valuation decision."

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03
FinanceEditor's Pick

Debt Snowball Calculator

"For anyone carrying multiple debts — this shows you the fastest path to zero."

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04
RetirementEditor's Pick

Financial Independence Number

"The one number everyone chasing FIRE needs to know. This calculates it properly."

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05
BusinessEditor's Pick

Enterprise Value Calculator

"More revealing than market cap alone — essential for comparing companies across sectors."

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06
PersonalEditor's Pick

Emergency Fund Calculator

"Before you invest a single dollar, make sure your safety net is sized correctly."

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07
HealthEditor's Pick

Caffeine Metabolism Calculator

"Surprisingly useful — find out when that afternoon coffee is still in your system at bedtime."

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08
IncomeEditor's Pick

Gross-to-Net Salary

"Every job offer looks better gross. This shows you what actually lands in your account."

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III.

Card Catalog

CAPM Calculator

#001
FIN
Calculate expected return using the Capital Asset Pricing Model

Capital Gains

#002
FIN
Estimate tax on short-term and long-term capital gains

Book Value Per Share

#003
FIN
Calculate per-share book value from balance sheet data

Current Yield

#004
FIN
Determine the current yield on a bond investment

Attrition Rate

#005
BIZ
Measure employee turnover over a given period

Cash Conversion Cycle

#006
BIZ
Days from paying suppliers to collecting from customers

Cost-Plus Pricing

#007
BIZ
Set selling price by adding markup to unit cost

Cost of Equity

#008
FIN
Calculate required return on equity using dividend or CAPM approach

Depreciation

#009
FIN
Calculate straight-line and accelerated depreciation schedules

Dual Income Mortgage

#010
FIN
See how two incomes affect home affordability

Early Payoff

#011
FIN
Find out how extra payments shorten your loan

Expense Ratio Comparison

#012
FIN
Compare long-term cost of fund expense ratios

CTR Calculator

#013
MKT
Calculate click-through rate for ads and emails

Affiliate Commission

#014
MKT
Estimate earnings from affiliate programs

Biweekly Pay

#015
INC
Convert annual salary to biweekly take-home pay

Child Tax Credit

#016
TAX
Estimate your child tax credit amount

Disposable Income

#017
INC
Calculate income after taxes and mandatory deductions

Auto Refinance Savings

#018
FIN
See if refinancing your car loan actually saves money

Customer Lifetime Value

#019
MKT
Estimate total revenue from a single customer relationship

Freelancer Tax Estimator

#020
TAX
Estimate quarterly self-employment taxes

Credit Card Payoff

#021
FIN
Plan your path to a zero credit card balance

Bond Coupon Payment

#022
FIN
Calculate periodic interest payments on bonds

Inventory Carrying Cost

#023
BIZ
Calculate the true cost of holding inventory

Family Budget Allocation

#024
HOME
Allocate household income across essential categories
IV.

Reading Room

①
Find

What's your debt payoff date?

Total balance$24,000
APR22.9%
Monthly payment$550
Payoff date67 months
Total interest$12,842
Calculate yours →
②
Calculate

Can you afford that mortgage?

Home price$380,000
Down payment15%
Rate / Term7.1% / 30yr
Monthly payment$2,189
Housing cost ratio31.2%
Calculate yours →
③
Decide

Is that freelance rate high enough?

Hourly rate$85
Billable hours/yr1,400
Self-employment tax15.3%
Net income$74,160
Effective hourly$52.97
Calculate yours →
V.

Reference Desk

Our calculators use well-established financial and mathematical formulas, and we review them regularly for accuracy. However, they are built for estimation and personal decision-making — not as a substitute for professional tax, legal, or accounting advice. For anything filed with a government agency or used in a legal proceeding, always have a licensed professional verify the numbers.
We review and update reference values — tax brackets, standard deductions, average interest rates — on a regular cycle, typically when new federal or state figures are published. Each calculator page shows the date its reference data was last updated. That said, always replace pre-filled defaults with your actual numbers for the most accurate results.
No catch. Every calculator on Nexengine is free to use — no account, no email, no trial period, no premium tier. We believe financial and practical tools should be accessible to everyone. Open any tool, enter your numbers, and get your result. That's it.
No. All calculations run entirely in your browser. Nothing you type is sent to our servers, saved in a database, or shared with third parties. When you close the page, your inputs are gone. We don't require accounts and we don't use cookies to track your calculations.
Every tool works on any modern browser — phone, tablet, or desktop. No app download needed. The layout adapts to your screen so you can run a quick calculation from the grocery store aisle or your couch just as easily as from your desk.