Math

45 tools

Industry Salary Benchmark Lookup

Look up 25th/50th/75th percentile monthly and annual salary benchmarks by industry, city tier, and job level.

Annual Leave & Time-Off Balance Calculator

Calculates statutory paid annual leave by tenure, then combines company extra leave, days already taken, and overtime comp hours into a total remaining leave balance.

Recruitment Cost & ROI Calculator

Aggregates agency fees, job board fees, referral bonuses, plus HR and interviewer time cost into total and per-hire recruitment cost with a breakdown.

Employee Turnover Rate Calculator

Calculates employee turnover rate by month, quarter, or year, separates voluntary from involuntary departures, and gives an annualized health rating.

Headcount Planning Calculator

Estimate required headcount from annual business volume and per-capita output, compare it with current staffing to find the gap, and estimate labor cost with optional average salary and budget cap. Built for HR headcount planning and hiring proposals.

Compensation Structure Builder

Enter base salary, performance base, performance coefficient, allowance and bonus months to instantly see monthly pay, annual pay, year-end bonus, component ratios and an estimated social insurance deduction, making compensation plan design and comparison easy.

Multi-Currency Exchange Rate Calculator

A free exchange rate calculator for 10 major currencies used in cross-border e-commerce. Reference rates are built in and fully editable, with single and batch conversion plus automatic cross-rate calculation.

VAT Calculator

Online VAT calculator for converting between net and gross amounts in both directions, with built-in 13%, 9%, 6%, 5%, 3% and 1% rates, optional surtax calculation and a batch mode.

Social Insurance Base Calculator

Enter your monthly salary and city to calculate the social insurance contribution base, including floor and ceiling handling, then see employer and employee contributions for pension, medical, unemployment, work injury and maternity insurance plus the housing fund, with adjustable rates.

Marketplace Fee Comparison Calculator

Compare fees, net income and profit margins across Amazon, eBay, Etsy, Shopify, AliExpress, Shopee and Temu. Enter price and cost, pick platforms, and see the best option highlighted automatically.

China Income Tax & After-Tax Salary Calculator

Work out your monthly China individual income tax and take-home pay from gross salary, personal social insurance and housing fund contributions, and special additional deductions. It also compares the two legal ways of taxing an annual one-time bonus and recommends the cheaper one.

FBA Storage Fee Calculator

Estimate Amazon FBA monthly and long-term storage fees. Converts dimensions to cubic feet automatically, switches peak (Oct-Dec) and off-peak rates, supports multiple months and inch/cm, lb/kg units.

Cross-Border Returns Cost Calculator

Measure the real cost of cross-border returns: return shipping, handling, depreciation on resellable items, full loss on unsellable items and exchange-rate loss, plus the break-even return rate.

PPC ACoS Calculator

Crunch Amazon PPC numbers in one click: ACoS, ROAS, TACoS and break-even ACoS, with profit/loss judgment against your margin and a suggested target CPC to guide bids.

Product Sourcing Cost Breakdown Calculator

Break down the full cost chain of cross-border sourcing — factory price, domestic logistics, packaging, QC, freight, insurance, tariff, VAT, port fees and FBA inbound — into landed cost per unit with cost-share bars.

Temu Supplier Price Calculator

Price products for Temu supply: derive a suggested supply price from your target margin, estimate the platform markup from the retail price, compare against competitor supply prices and get a margin-level assessment.

Shopee Commission Calculator

Enter your selling price, cost, marketplace and category to estimate Shopee commission, transaction fees and campaign service fees, then see your net profit and margin.

Work Seniority Calculator

Add up multiple periods of employment to get your total work seniority in years, months and days, along with the statutory paid annual leave entitlement that goes with it under China's Regulations on Paid Annual Leave for Employees.

Lazada Fee Calculator

Enter your selling price, cost, weight, marketplace and category to estimate Lazada commission, payment fees and LGS logistics fees, including a cross-border surcharge, and see your net profit and margin.

Linux File Permission (chmod) Calculator

Tick the read, write and execute boxes for owner, group and others to generate the octal chmod code, the symbolic notation and the full chmod command; you can also type an octal code and have the checkboxes filled in for you.

TikTok Shop Commission Calculator

Enter your selling price, cost, site and influencer commission rate to estimate TikTok Shop platform commission, transaction fees and influencer fees, with an automatic comparison against self-broadcast selling.

Multi-Model Token Cost Comparison

Compare API costs across 20 mainstream LLMs by pasting text or entering token counts, with per-call, daily and monthly cost rankings to pick the most cost-effective model.

AI Image Resolution Calculator

Pick an AI image model and enter your image size to find the best supported resolution, covering SDXL, Midjourney, DALL-E 3, Flux and more, with scale or crop hints.

OpenAI Batch API Cost Estimator

Estimate the cost of OpenAI Batch API requests (about 50% off) versus the synchronous API, with manual input and JSONL file modes and built-in reference prices for major models.

Age Calculator

Calculate age online from a date of birth. The tool gives the exact age in years, months and days, plus the total number of days and weeks lived and how many days remain until the next birthday.

Decision Matrix Calculator

Define weighted criteria, score each option from 1 to 5, and get weighted totals with a clear ranking to support rational decisions.

Presentation Time Calculator

Set your total presentation time and per-segment durations, then get a timeline with start/end times and remaining or over-time warnings.

Workstation Energy Cost Calculator

Enter the devices on your workstation with power and daily usage, get daily, monthly and yearly electricity costs and carbon emissions, plus a laptop-vs-desktop comparison.

Procrastination Cost Calculator

Calculate how much delay really costs you. Enter planned start, actual start and completion times plus an optional hourly rate to see delay hours, money wasted, annualized loss and an efficiency index, with blunt feedback and practical tips.

Newsletter Unsubscribe Rate Calculator

Calculate delivery, open, click, unsubscribe and complaint rates for an email campaign and compare them with industry benchmarks for e-commerce, SaaS, media, B2B and education, with a health score and improvement suggestions.

Sample Size Calculator

Compute the minimum sample size for statistical surveys using the Cochran formula, with finite population correction, confidence level comparisons, full calculation steps and practical advice.

SLA Uptime Calculator

Enter an SLA percentage to instantly get the allowed downtime per year/month/week/day, or enter actual downtime to work backward to an uptime percentage — includes a standard SLA-tier reference table.

Bandwidth Transfer Time Calculator

Enter a file size, network bandwidth, and transfer efficiency percentage to instantly get theoretical and actual transfer time plus the effective data volume, with a comparison table across common bandwidth tiers.

Cloud Server Cost Estimator

Enter your cloud provider, instance configuration (vCPU/memory/disk/traffic), and payment model to estimate monthly cost for AWS, Alibaba Cloud, and Tencent Cloud using built-in reference pricing, with a cross-provider comparison — figures are estimates, not live quotes.

RAG Embedding Cost Estimator

Enter document size, chunking parameters, an embedding model, and expected query volume to estimate a RAG system's indexing embedding cost, vector storage size, and ongoing query cost, comparing the annual total across popular embedding models.

FX Hedging Cost Calculator

FX hedging cost calculator for cross-border e-commerce sellers: compare no hedge, forward contract and option hedge, compute settlement gains/losses and hedging cost.

Tmall Global Fee Calculator

Tmall Global seller fee calculator: enter sale price, category commission rate and other fees to compute platform deduction, seller revenue, gross profit per unit, gross margin and break-even price.

Ad Budget Allocation Calculator

Enter total budget and per-channel CPC, conversion rate, average order value and margin; the tool allocates budget by channel effectiveness and estimates orders and profit, with manual fine-tuning.

Competitor Price Monitor Simulator

Paste a competitor price history to get min/max/avg/latest price stats, fluctuation analysis and a trend chart, plus a suggested selling range based on your cost. Pure front-end simulation with no web scraping.

China Maternity Leave Calculator

Free maternity leave calculator based on 2026 policy in mainland China. Enter the delivery date and province to work out maternity leave days, paternity leave days and the exact start and end dates, covering all 31 provinces with support for normal delivery, difficult delivery and multiple births.