Free Finance Tools & Calculators
Browse 356+ free interactive finance calculators, estimators, and utilities. 100% free, private, and runs directly in your browser without signup.
Direct Material Price Variance (MPV) & Quantity Variance Calculator — nrtechstudio
Calculator for direct material price variance (MPV), material quantity variance (MQV), and total direct material variance with automatic favorable/unfavorable classification.
Discretionary Income Calculator — Dept of Education & BEA Definitions (2026)
Free discretionary income calculator: Department of Education definition (AGI minus 150% of the 2026 HHS poverty guideline), BEA budgeting definition, IDR student-loan payment what-if, and the full 2026 poverty guideline table. 100% client-side.
Disposable Income Calculator — Gross to Disposable, Allocation & Savings Rate
Calculate disposable income (gross − taxes − mandatory contributions), 50/30/20 allocation, savings rate, and compare salary-raise scenarios. Free, 100% in your browser.
Distance Attenuation Calculator — Sound Level Drop Over Distance | nrtechstudio.com
Free distance attenuation calculator: enter the SPL at a reference distance and get the sound level at any target distance using L2 = L1 − 20·log10(d2/d1) for point sources (or 10·log10 for line sources). Includes reverse mode, distance–SPL table, and 16 FAQs. 100% in-browser, no sign-up.
Dividend Discount Model (DDM) Calculator — Gordon Growth Model
Estimate a stock's fair value with the Dividend Discount Model: single-stage Gordon Growth, two-stage (multi-stage) DDM, implied-growth solver from market price, and an r × g sensitivity table.
Dividend Payout Ratio Calculator — Formula, Solver & Comparator
Calculate dividend payout ratio (total dividends ÷ net income × 100%), reverse earnings/dividend solver, retention ratio & sustainable growth rate, and compare two companies. Free.
Stock Dividend Calculator — Total Dividends, Projections & DRIP
Calculate stock dividend amounts: total dividends from DPS × share count, target-dividend solver, dividend growth projections, and DRIP simulation. Free, 100% in your browser.
Divorce Cost Calculator — Uncontested vs Mediation vs Contested (2026) | nrtechstudio.com
Free divorce cost calculator: compare uncontested, mediation & contested divorce costs with per-state filing fees (50 states), complexity adjuster, timelines, hidden costs & mediation vs litigation break-even. Educational estimates — not legal advice.
Dog Calorie Calculator — Daily kcal by Weight, Age & Activity | nrtechstudio.com
Free dog calorie calculator: estimate daily kcal needs with the veterinary RER formula (70×W^0.75) × life-stage factors. Includes meal planner, 10% treat budget, kcal→grams/cups food converter and a weight-loss planner.
Dog Quality of Life Calculator — HHHHHMM Scale (2026) | nrtechstudio.com
Free dog quality of life calculator based on the HHHHHMM scale (Hurt, Hunger, Hydration, Hygiene, Happiness, Mobility, More good days than bad). Score 7 factors, track trends over time, and print a summary for your vet. Private, no signup.
DSCR Loan Calculator — Debt Service Coverage Ratio for Rental Property
Free DSCR loan calculator: compute debt service coverage ratio from rental income, vacancy and operating expenses. Includes max loan solver and break-even occupancy.
DUI Cost Calculator by State 2026 — Fines, Lawyer, SR-22 & 10-Year Total | DUI Cost Lab
How much does a DUI cost? Estimate the true total: 50-state fine & fee database, first vs repeat offense, DUI lawyer cost, bail, SR-22 insurance increase by state, ignition interlock, DUI school, and 10-year total cost. Free, 100% client-side. Educational estimates — not legal advice.
DuPont Analysis Calculator — 3 & 5 Factor ROE Decomposition
Free DuPont analysis calculator: decompose ROE into profit margin × asset turnover × leverage (3 factors) or 5 factors, compare two companies, and understand ROE drivers. 100% in your browser.
EAR Calculator — Estimated Average Requirement (DRI) Checker
Free EAR calculator: compare your daily vitamin and mineral intake against IOM Dietary Reference Intakes (EAR, RDA, AI, UL) by age, sex, pregnancy, and lactation. 29 nutrients, instant adequacy check.
Early Loan Payoff Calculator — Pay Off Your Loan Faster
Free early loan payoff calculator: enter balance, APR, and payment to see your payoff date, compare lump sum vs extra monthly vs biweekly strategies, check prepayment penalty break-even, and export a full amortization schedule. 100% private, runs in your browser.
Early Retirement (FIRE) Calculator — Years to FI, Withdrawal Simulator, SS Bridge
Free early retirement (FIRE) calculator: years to financial independence, FIRE number, 3%/4%/5% withdrawal simulator with sequence risk, Social Security bridge gap, and pre-Medicare healthcare gap.
Earnest Money (Deposit) Calculator — nrtechstudio.com
Property earnest money calculator: compute the amount from price × percent, reverse solver, cancellation scenario simulation, and two-offer comparator.
EASI Score Calculator (Eczema Area and Severity Index) — nrtechstudio.com
Free EASI score calculator: compute the Eczema Area and Severity Index (0–72) from the 4 body regions, sign intensities 0–3 and area scores, with Lesh
EBIT Calculator — Earnings Before Interest & Taxes (Top-Down & Bottom-Up)
Free EBIT calculator: compute Earnings Before Interest and Taxes top-down from revenue or bottom-up from net income. Get EBIT margin, toggle D&A for EBITDA, and compare against industry benchmarks.
EBITDA Multiple Calculator — Company Valuation (EV = EBITDA × Multiple)
Free EBITDA multiple calculator: compute enterprise value from EBITDA × multiple, reverse solver, 2-company comparator, sensitivity analysis, and industry EV/EBITDA reference table. Educational estimate, not investment advice.
ECG Boxes to Seconds Converter — Small & Large Box Time Calculator
Convert ECG paper boxes to seconds and milliseconds. Standard 25 mm/s and 50 mm/s paper speeds. 1 small box = 0.04 s, 1 large box = 0.2 s. Two-way con
ECG Heart Rate Calculator — 1500, 300 & 6-Second Method
Calculate heart rate from an ECG strip: the 1500 method (small boxes), 300 method (large boxes), 300-150-100-75-60-50 count-off, and the 6-second QRS
EVA (Economic Value Added) Calculator — Compute a Company’s Economic Profit
EVA (Economic Value Added) calculator: compute economic profit from NOPAT, WACC, and invested capital. Compare ROIC vs WACC, breakeven WACC solver, and 2-company comparison. Free, 100% in your browser.
Effective Interest Rate Calculator
Free effective interest rate calculator: true yearly cost of a loan including origination and other fees (simple total-cost method), add-on installment loan effective rates, and side-by-side loan comparison.
Egg Freezing Calculator — Live Birth Chances from Frozen Eggs (Oocyte Cryopreservation)
Estimate your chance of a live birth from frozen eggs by age at freezing and number of oocytes. Binomial model calibrated to Doyle 2016 & Goldman
EIC Calculator 2026 — Earned Income Tax Credit Estimator
Free 2026 EIC/EITC calculator: estimate your Earned Income Tax Credit by income, filing status and qualifying children. IRS Rev. Proc. 2025-32 figures. 100% client-side.
Electric Motor Torque Calculator — HP, RPM & Torque
Free electric motor torque calculator. Solve for torque (T = HP × 5252 / RPM), horsepower, or RPM in imperial (lb-ft) or metric (N·m, kW) units. Instant, accurate, no sign-up.
Electrical Box Fill Calculator — NEC 314.16 Box Fill & Box Sizer
Free NEC 314.16 electrical box fill calculator: conductors, devices, clamps, grounds and 2023 terminal blocks. Check any box or size the minimum box.
Electrical Unit Converter — Ohm's Law, Resistor Codes & Wire Sizes | nrtechstudio
Free electrical unit converter: volts, amps, ohms, farads & more, plus an Ohm
ELSS Calculator - Return Projection, 80C Tax Benefits & 3-Year Lock-in Tracker
Free ELSS calculator: lumpsum & SIP projections, Section 80C tax savings up to Rs 1.5 lakh, ELSS vs PPF vs NSC comparison, and track the 3-year lock-in of each SIP installment.
Emergency Fund Calculator — How Much to Save by Job Type | nrtechstudio.com
Free emergency fund calculator: risk-based targets by job type (stable employee, freelancer, contract, single-income), essential-expense builder, savings plan, tier system and emergency drain simulator. 100% client-side, private, no signup.
EMV (Expected Monetary Value) Calculator — Compute Expected Monetary Value & EVPI
Free EMV calculator: compute Expected Monetary Value for one decision, compare 2 alternatives, and compute EVPI (value of perfect information). Includes formulas, worked examples, an interpretation table, and FAQ.
Ending Inventory Calculator: FIFO, LIFO, Weighted Average
Compute ending inventory with FIFO, LIFO, and weighted-average methods. Complete with COGS, gross profit, a 3-method comparator, and verified examples.
Energy Cost Calculator -- kWh to Cost (Flat, Tiers, Time-of-Use) | nrtechstudio.com
Free energy cost calculator: convert watts and kWh to electricity cost with flat tariffs, tiered slabs, time-of-use rates, budget reversal, efficiency comparisons, and country tariff comparison. 100% client-side, no data leaves your browser.
Photon Energy to Wavelength Converter — eV to nm Calculator | nrtechstudio.com
Free photon energy to wavelength calculator. Convert eV, joules, kJ/mol to wavelength (nm, µm, Å) and back. Get frequency, wavenumber, spectrum band and visible color. E = hc/λ, 100% in your browser.
Energy Unit Converter — Joules, kWh, BTU, kcal + Cost & Fuel Calculator | nrtechstudio
Free energy unit converter: joules, kJ, calories, kcal, Wh, kWh, MWh, eV, BTU, therm, ft-lb, tonne of oil equivalent. Plus electricity cost calculator, food energy (kcal↔kJ) with exercise equivalents, fuel equivalents, and a mini home energy audit. 100% client-side.
Engine Hours to Miles Converter | Fleet Maintenance Estimator
Convert engine hours to equivalent miles (and miles back to hours) with duty-cycle presets for semi trucks, vans, and equipment. Free fleet maintenance scheduling helper.
EOQ (Economic Order Quantity) Calculator: Formula, Examples & Reorder Point
Compute EOQ (economic order quantity) with the √(2DS/H) formula: optimal order quantity, order frequency, interval, total cost, reverse solver, reorder point + safety stock, and a 2-scenario comparator.
EPF Calculator — India & Malaysia (KWSP) Retirement Fund Projection
Free EPF calculator: Employees’ Provident Fund balance projection for India (EPFO) & Malaysia (KWSP), target-based contribution solver, and 2-scenario comparison. In English.
EPS Calculator — Earnings Per Share (Basic, Diluted, P/E, YoY Growth)
Free EPS calculator: basic earnings per share, time-weighted shares, diluted EPS via the treasury stock method, P/E ratio, and year-over-year EPS growth — with step-by-step workings.
2026 Estimated Tax Calculator — 1040-ES Quarterly Payments & Safe Harbor
Compute 2026 quarterly estimated tax (1040-ES): 90%/110% safe harbor, 15.3% SE tax, due dates & penalty estimate. Education, not tax advice.
Exit Rate Calculator: Compute Page Exit Rate & Compare with Bounce Rate
Free exit rate calculator: compute webpage exit rate (exits ÷ pageviews), compare exit rate vs bounce rate, descriptive internal categorization, and investigation questions when exit rate is high.
Expected Return Calculator — Scenarios, CAPM & Portfolio
Compute investment expected return: probability-weighted scenarios, CAPM model (beta & risk premium), portfolio expected return up to 10 assets, and 2-asset portfolio risk. Educational estimate, not investment advice.
Faraday to Coulomb Converter & Electrolysis Calculator
Convert faraday to coulomb, kilocoulomb, milifaraday & ampere-hour. Calculate mass deposited with Faraday
FCR Calculator — Feed Conversion Ratio for Poultry & Livestock
Free FCR calculator: compute feed conversion ratio for broilers, layers, pigs, cattle, tilapia and more. Includes target feed planner, cost per kg of gain, mortality-adjusted & economic FCR, and a multi-batch tracker.
Fertilizer Calculator — NPK Rate, Bags Needed & Cost | nrtechstudio.com
Free fertilizer calculator: enter your lawn or garden area, target nitrogen rate and N-P-K analysis to get exact product pounds, bags needed, nutrient breakdown, cost estimate and spreader settings. Works in imperial and metric.
FHA Loan Calculator — Monthly Payment, UFMIP & MIP
FHA loan calculator: compute the full monthly payment (P&I + MIP + tax + insurance), compare financed vs upfront UFMIP, and estimate when MIP ends. Mortgagee Letter 2023-05 rules.
Fibonacci Retracement & Extension Calculator — Trading Levels
Calculate Fibonacci retracement (23.6%–100%) and extension (100%–423.6%) levels for stock, forex, and crypto trading. Free, 100% in-browser, with FAQ and worked examples.
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How to Use the Tools Directory
Every tool is a single interactive page: enter your inputs, get instant results, no account needed. Use the search box (shortcut: press /) to jump straight to a tool, or browse categories when you are exploring. Each card links to the tool's permanent URL, which you can bookmark or share.
Because all computation happens in your browser, the tools are fast, private, and free forever. If a result looks wrong, use the one-click report control on the tool page so it can be fixed.
Tool Categories at a Glance
| Category | What you will find | Example tasks |
|---|---|---|
| Developer | Encoders, formatters, regex, network tools | Format JSON, test regex, subnet a network |
| Finance | Tax, loans, salary, investing | Estimate tax brackets, amortize a loan |
| Home improvement | Estimators, measurements, materials | Size a wire, estimate paint or flooring |
| Health & fitness | Body metrics, nutrition, workouts | Track BMI, plan calories, score fitness tests |
| Math & science | Converters, geometry, statistics | Convert units, solve triangles |
| Text | Counters, sorters, generators | Count words, alphabetize a list |
| Color | Pickers, converters, checkers | Convert HEX to RGB, check contrast |
| Everyday life | Cooking, travel, automotive, pets | Convert recipes, plan fuel costs |
Popular Tasks and Where to Start
| I want to... | Start with | Why |
|---|---|---|
| Convert between number bases | Binary Converter | Step-by-step base conversion with charts |
| Validate and format data | JSON Formatter | Pretty-print and check JSON instantly |
| Count words for an essay | Word Counter | Words, characters, reading time |
| Check password strength | Password Strength Meter | Entropy-based strength scoring |
| Grade text readability | Readability Score | Flesch-Kincaid and grade levels |
| Audit color contrast | Accessibility Checker | WCAG contrast ratios in one click |
Tools Directory FAQ
What is the NRTechStudio tools directory?
It is a free catalog of more than 2,700 interactive web tools: calculators, converters, generators, and checkers for developers, finance, home improvement, health, education, and everyday tasks.
Are all the tools really free?
Yes. Every tool in the directory is free to use with no sign-up, no trial, and no paywall. They run entirely in your browser.
Do I need to create an account?
No. There are no accounts, logins, or subscriptions. Open a tool and use it immediately.
Is my data private when I use these tools?
Yes. The tools are 100% client-side: your inputs are processed by JavaScript in your own browser and never sent to a server.
How do I find the right tool?
Use the search box at the top of the directory (press / to focus it), or browse by category. Every tool card shows a short description of what it computes.
Do the tools work on mobile?
Yes. The directory and the tools use responsive layouts that adapt to phones, tablets, and desktops.
How many tools are there?
The directory holds more than 2,700 tools and grows regularly as new calculators and converters are published.
Can I request a new tool?
Yes. Each tool page has a report/feedback control you can use to request features or new tools; requests help prioritize what gets built next.
Are the tools accurate?
Calculators use published formulas and reference data (tax tables, NEC ampacity, standard conversions). Each tool page documents its method, and issues can be reported in one click for a fix.
Do tools work offline?
Once a tool page has loaded, most tools keep working without a connection because the logic is client-side JavaScript. The directory search needs the page loaded first.
What categories are covered?
Developer utilities, finance and tax, home improvement, health and fitness, math and science, text tools, color tools, networking, education, and everyday life calculators, among others.
Can I bookmark or share a tool?
Yes. Every tool has its own permanent URL under nrtechstudio.com/tools/, which you can bookmark or share directly.
Is there an API for these tools?
The tools are interactive web pages, not API endpoints. The underlying math is plain JavaScript you can inspect in the page source.
Why do some tools show ratings?
Ratings aggregate user feedback to surface the most trusted tools and flag pages that need fixes or better explanations.
How often are new tools added?
New tools are published on a continuous pipeline, prioritized by measured search demand and by user requests from the feedback controls.
Who builds these tools?
NRTechStudio, an independent tools studio focused on free, private, client-side utilities that respect user privacy.