Free Online Business Calculators & Tools
Free online business calculators are all the tools on Calcrux in one place — so you can run any business number without juggling spreadsheets or paying for a premium app. The library spans five areas of work: ecommerce selling, India business and payroll, manufacturing and operations, startup and funding decisions, and everyday financial planning. Every tool works right in your browser with no signup, gives you an answer in seconds, and explains what the result actually means. Pick an ecosystem below, search by name, or jump straight to a popular calculator. New tools are added regularly, and existing ones are kept accurate as fees and rates change.
- Find the right calculator fast by browsing five ecosystems or searching by tool name or keyword
- Work out ecommerce profit, marketplace fees, pricing, ROAS, and inventory in a few clicks
- Plan business finances, take-home salary, loans, cash flow, and investments for free
- Run startup math like burn rate, runway, and equity dilution before your next decision
- Switch between 9 countries and currencies so every result fits your market
Browse by ecosystem
Ecommerce Seller Operations
50 tools live
India Business Operations
38 tools live
Manufacturing & ERP Operations
5 tools live
Startup & Business Intelligence
5 tools live
Operational Financial Planning
7 tools live
105 tools live · more added regularly
Featured
Popular starting points
Amazon FBA Profit Calculator
Calculate your true Amazon FBA profit, margin, and ROI in seconds.
GST Calculator
Add or remove GST and split CGST, SGST & IGST — with current GST 2.0 rates.
OEE Calculator
Availability, performance, quality, and the Six Big Losses — in one view.
Startup Burn Rate Calculator
Gross vs net burn, cash runway, and bear/bull scenarios — instantly.
SIP Calculator
Project your SIP maturity, total returns, and real worth after inflation — free.
Showing all 105 tools
All 105 tools, grouped by ecosystem.
Ecommerce Seller Operations (50)
View all →Amazon FBA Profit Calculator
Calculate your true Amazon FBA profit, margin, and ROI in seconds.
Profit Margin Calculator
All three P&L margins stacked in one view, with markup conversion — any currency.
Amazon Ads ROAS Calculator
True Amazon ad ROAS, break-even, and the max CPC you can profitably bid.
Shopify Profit Calculator
Shopify profit after plan fee, processing and ads — and when to upgrade.
eBay Fee Calculator
Real eBay profit after all six fees — and store subscription break-even.
Etsy Fee Calculator
Real Etsy profit after all five fees — including the $10K Offsite Ads trap.
Selling Price Calculator
Pick your channel, set your target margin — get the exact price that nets it after real marketplace fees.
Walmart Fee Calculator
Real Walmart profit after referral fee, WFS, and $0 monthly fees.
Economic Order Quantity (EOQ) Calculator
The EOQ calculator with orders/year, cycle days, and bulk discount check.
LTV CAC Calculator
LTV:CAC ratio, payback, and max CAC you can afford — on gross profit.
GMROI Calculator
Your GMROI, the ~3.2 retail benchmark verdict, and both levers that move it.
Break-Even ROAS Calculator
Minimum profitable ROAS for any channel — break-even, target, and ACoS.
Amazon PPC Break-Even Calculator
Break-even ACoS, max CPC, and min CVR — from your product economics.
Amazon FBA Restock Calculator
Reorder point, days to reorder, and order quantity — no spreadsheets needed.
Inventory Turnover Calculator
Inventory turnover, DSI, and supply weeks — with a benchmark verdict.
Average Order Value Calculator
Calculate your AOV, get a free-shipping floor, and model what a lift is worth.
Discount & Promotion Profit Calculator
Before you run a discount, see the exact volume it needs and your safe floor.
Cart Abandonment Calculator
Cart abandonment rate, lost revenue, and how much you can realistically recover.
Dimensional Weight Calculator
Dimensional, billable, and chargeable weight — all carriers, lb or kg.
Flipkart Fee Calculator
Your Flipkart settlement, profit, and every fee — by category, tier, and COD.
Cost Per Acquisition (CPA) Calculator
Calculate CPA, break-even threshold, and whether each acquisition is profitable.
Marketing ROI Calculator
Measure marketing ROI from gross profit to LTV-adjusted return on spend.
Contribution Margin Calculator
Calculate contribution margin per unit, CM ratio, and break-even point.
Customer Retention Rate Calculator
Retention rate, churn rate, and the revenue value of keeping one more customer.
Ad Spend Scaling Simulator
Simulate profit, ROAS, and marginal return of scaling your ad budget.
Amazon ACOS Calculator
Calculate Amazon ACOS, break-even ACOS, and net profit from your ad campaigns.
Amazon TACoS Calculator
Calculate Amazon TACoS and see if ads build organic rank or just buy clicks.
Product Profitability Calculator
Per-unit profit, margin, ROI, and monthly projections — fees and ads included.
Ecommerce Unit Economics Calculator
Contribution margin, break-even units, and monthly P&L from variable costs.
Customer Payback Period Calculator
Find out how many months to recover your CAC — the metric that limits scale.
Marketing Efficiency Ratio (MER) Calculator
Measure blended MER across all channels — the true sign of marketing health.
Amazon Referral Fee Calculator
Look up the exact Amazon referral fee for any category and selling price.
Amazon Storage Fee Calculator
Calculate Amazon FBA monthly and long-term storage fees by size tier and season.
Amazon IPI Score Calculator
Estimate your IPI score and find which factor is pulling it below 400.
Revenue Projection Calculator
Project 3–24 months of revenue from run rate, growth rate, and seasonality.
Markup Calculator
Find your selling price, markup %, or margin from any two inputs — any currency.
Break-Even Point Calculator
Find exactly how many units you need to sell before every extra sale is profit.
Ecommerce Conversion Rate Calculator
Calculate CVR, model revenue impact, and pinpoint your biggest funnel drop-off.
Dropshipping Profit Calculator
See your real dropshipping margin after ads, fees, shipping, and returns.
Landed Cost Calculator
Find your true per-unit import cost after freight, duty, and fees.
Customer Lifetime Value Calculator
Know what a customer is really worth — margin CLV, DCF CLV, and max CAC.
Product Pricing Calculator
Back-solve the selling price that hits your exact target net margin after all costs.
Ecommerce ROI Calculator
Calculate ROI, net margin, and payback period on your ecommerce investment.
Wholesale Pricing Calculator
Set wholesale prices that protect your margin and give retailers room to sell.
Return Rate Calculator
Calculate return rate, full return cost, and what a 1% reduction saves.
Inventory Forecast Calculator
Project demand for 30–90 days with growth trend and seasonal adjustment.
Reorder Point Calculator
Calculate the exact inventory level to trigger your next order — no stockouts.
Inventory Carrying Cost Calculator
Calculate the true annual cost of holding inventory — all cost components.
Stock Coverage Calculator
See how many days your stock will last and whether a stockout is coming.
Dead Stock Calculator
Quantify dead stock costs and decide: liquidate, discount, or hold.
India Business Operations (38)
View all →GST Calculator
Add or remove GST and split CGST, SGST & IGST — with current GST 2.0 rates.
In-Hand Salary Calculator
Convert CTC to monthly take-home with full tax and deduction breakdown.
Income Tax Calculator India
Your total income tax for the year — old vs new regime compared, FY 2025-26.
Gratuity Calculator
Calculate gratuity under the Payment of Gratuity Act — and your tax-free amount.
TDS Calculator
Tax deducted at source on a payment — the right rate and amount by section.
Advance Tax Calculator
Pay your income tax in instalments through the year — amounts and due dates.
Professional Tax Calculator
The state tax on your payslip — PT by state, separate from income tax.
NPS Calculator
Project your NPS corpus, tax-free lump sum and monthly pension at 60 — free.
PPF Calculator
Project your PPF maturity and tax-free interest — yearly or monthly deposits.
PPF Goal Calculator
Work backwards from your PPF goal to the exact yearly deposit you need.
HRA Calculator
Exact HRA exemption with a full 3-rule breakdown — free for FY 2025-26.
EPF Calculator
Project your EPF corpus, interest earned, and EPS pension at retirement.
Freelancer Tax Calculator
Section 44ADA tax, advance tax, GST estimate and audit check — free.
Sukanya Samriddhi Yojana Calculator
Project your Sukanya Samriddhi (SSY) maturity at 21 — tax-free at 8.2%.
FD Calculator
See your fixed deposit maturity, interest and TDS — quarterly compounding.
RD Calculator
See your recurring deposit maturity and interest — and the TDS on it.
NSC Calculator
See your NSC maturity and interest at 7.7% — the 5-year certificate.
SCSS Calculator
See your Senior Citizen Savings Scheme quarterly income at 8.2%.
Post Office MIS Calculator
See your monthly income from the Post Office MIS at 7.4%.
KVP Calculator
See how fast Kisan Vikas Patra doubles your money at 7.5%.
APY Calculator
Find your Atal Pension Yojana monthly contribution by age.
Capital Gains Tax Calculator
Work out STCG and LTCG tax on shares, property and gold.
80C Calculator
Add up your 80C investments and the tax you save.
TDS on Salary Calculator
See the monthly TDS your employer cuts from your salary.
Salary Hike Calculator
Find your hike percentage or new salary after a raise.
Leave Encashment Calculator
Value your unused leave and its tax-free part.
Statutory Bonus Calculator
Work out your statutory bonus under the Payment of Bonus Act.
GST Late Fee & Interest Calculator
Work out the GST late fee and 18% interest on a late return.
Home Loan Tax Benefit Calculator
See the tax you save on your home loan interest and principal.
80D Calculator
Find your health-insurance tax deduction for family and parents.
80E Calculator
Find the tax you save on your education loan interest.
80G Calculator
Find your tax deduction on donations to charities and funds.
80TTA & 80TTB Calculator
Tax-free deduction on your savings and deposit interest.
Salary Breakup Calculator
Split your CTC into Basic, HRA, PF, gratuity and take-home.
EMI Calculator
Find your monthly EMI, total interest and full repayment breakdown.
Loan Prepayment Calculator
See the interest you save and how much sooner you finish.
Loan Eligibility Calculator
See how much loan you qualify for on your income (FOIR).
Loan Balance Transfer Calculator
See the interest you save by switching to a lower rate.
Manufacturing & ERP Operations (5)
View all →OEE Calculator
Availability, performance, quality, and the Six Big Losses — in one view.
MTBF & MTTR Calculator
Mean time between failures, mean time to repair, and machine availability.
Takt Time Calculator
Set your production pace: takt time, required output rate, and line status.
Production Capacity Calculator
Theoretical, effective, and net capacity — for machines, shifts, and efficiency.
Safety Stock Calculator
Safety stock, reorder point, and holding cost for any service level target.
Startup & Business Intelligence (5)
View all →Startup Burn Rate Calculator
Gross vs net burn, cash runway, and bear/bull scenarios — instantly.
Unit Economics Calculator
LTV, CAC, LTV:CAC ratio, and CAC payback — with the 3× benchmark.
SaaS Metrics Calculator
MRR waterfall, ARR, NRR, and Quick Ratio — the four metrics boards ask for.
Equity Dilution Calculator
Pre/post-money valuation, investor stake, and founder dilution — per round.
Startup Break-Even Calculator
Break-even units and revenue, contribution margin, and pricing sensitivity.
Operational Financial Planning (7)
View all →SIP Calculator
Project your SIP maturity, total returns, and real worth after inflation — free.
Lumpsum Calculator
What a lumpsum investment grows into — total value, real worth, year by year.
Compound Interest Calculator
Compound interest on a balance and deposits — final balance, APY and real worth.
SIP vs Lumpsum Calculator
Compare SIP vs lumpsum on the same sum — verdict, gap, and when each wins.
SIP Goal Calculator
Work backwards from your goal to find the exact monthly SIP you need.
FIRE Calculator
Your FIRE number, the earliest age you can retire, and whether it survives.
Retirement Calculator
Find the corpus you need and the monthly SIP to get there.
Explore by area
Browse by ecosystem
Five focused areas of business operations. Pick the one that fits your work.
Ecommerce Seller Operations
Profit, inventory, shipping, and ads tools for marketplace sellers
India Business Operations
HR, salary, GST, and business finance tools for Indian businesses
Manufacturing & ERP Operations
Production planning, costing, and maintenance tools for manufacturers
Startup & Business Intelligence
Runway, fundraising, equity, and growth tools for founders
Operational Financial Planning
Personal finance, business planning, and risk analysis tools
Frequently asked questions
Everything you need to know about the Calcrux tool library.
01Are all the calculators on Calcrux free to use?
Yes. Every calculator and tool in the Calcrux library is completely free, with no signup, no account, and no paywall. You can run as many calculations as you like, including features that rival paid apps charge for.
02How accurate are the calculators?
Very accurate — formulas follow authoritative sources, and third-party fee schedules (Amazon, Flipkart) are stored centrally and updated when platforms change them. Every engine is covered by automated tests so the math stays reliable.
03Which countries and currencies do the tools support?
Calcrux supports nine countries and currencies, including the US, India, UK, Australia, Canada, UAE, Singapore, Germany, and France. Results, tax labels, and number formatting adapt automatically, and you can switch regions anytime using the region selector.
04How do I find the right tool quickly?
You can browse by ecosystem (ecommerce, India business, manufacturing, startup, or financial), use the on-page search to filter by name or keyword, or open a related-tools link from any calculator you are already using.
05Do I need to download anything or install an app?
No. Every calculator runs directly in your web browser on desktop or mobile. There is nothing to download, install, or update, and your inputs stay on your device.
06What types of business calculators does Calcrux offer?
Calcrux covers five areas: Ecommerce (Amazon, eBay, Etsy profit and fees), India Business (salary, GST, payroll), Manufacturing (OEE, takt time), Startup (burn rate, equity), and Financial Planning (SIP, compound interest, loans). All free.
07Can I use these calculators on my phone?
Yes. All calculators are built mobile-first and work in any phone browser with no app to install. Inputs stack for small screens, results adapt to any screen size, and every button is large enough to tap.
08Does Calcrux save or store my calculation inputs?
No. Calculations run locally in your browser and your numbers are never sent to a server or stored anywhere. Close the tab and the data is gone — no account needed and nothing is tracked.
09How often are fee schedules and third-party rates updated?
When platforms publish changes. Fees like Amazon FBA, Flipkart commissions, and tax slabs are stored centrally — one update refreshes every dependent calculator. Each tool FAQ notes the source and last-reviewed date.
10Who are the Calcrux tools designed for?
Anyone working in or running a business: ecommerce sellers checking margins, HR teams computing payroll, manufacturers tracking OEE, startup founders modelling runway, and individuals planning investments or loans.