All Calculators

Every calculator on TraderH4, grouped by topic. Each one is free, works on mobile, and explains exactly how the result is worked out.

Tax Penalty Calculators

Estimate IRS underpayment and late-payment penalties and interest.

IRS Underpayment Penalty Calculator Estimate the Form 2210 penalty for underpaying estimated tax, including safe-harbor checks.
Late Tax Payment Penalty Calculator Estimate IRS failure-to-file, failure-to-pay penalties and interest on a late tax balance.

Severance & Redundancy Calculators

Estimate severance pay and statutory redundancy across the US, UK and Canada.

Freelance & Business Calculators

Price your work and plan your income as a freelancer or contractor.

Freelance Hourly Rate Calculator Turn an income goal into the hourly and day rate you need as a freelancer or contractor.