What do you need to calculate ?

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Cancellation Deadline Calculator

What is the last day I can cancel before my subscription or contract renews?

renewal − N days

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Overtime Pay Check (US Federal FLSA)

Was I paid enough for my overtime this week under federal law?

1.5 × rate × (h − 40)

Money & Finance

Loans, interest, investment returns

Loan Payment Calculator

What is my monthly payment and total interest on a fixed-rate loan?

P·r / (1 − (1+r)⁻ⁿ)

Compound Interest Calculator

How much will my savings grow with compound interest and monthly deposits?

Bₜ₊₁ = Bₜ(1+i) + C

NPV, IRR & Payback Calculator

When does my investment pay back, and what is its NPV and IRR?

Σ CFₜ / (1+r)ᵗ

Currency Converter (Your Rate)

What is this amount in another currency at the rate I was quoted?

amount × rate × (1+fee)

Credit Card Payoff Calculator

How long will it take to pay off my card at a fixed monthly payment, and how much interest will I pay?

nper(r, −P, B)

Savings Goal Calculator

How much do I need to save each month to reach my goal?

−pmt(r, n, −PV, FV)

12 · rate(n, −pmt, P − fees)

Loan APR Calculator (with Fees)

What is the true annual rate of a loan once fees and points are included?

Bond Yield to Maturity Calculator

What yield to maturity does this bond price imply, and what is its duration?

Σ c·v^(k+w) = P_dirty

%Combines 1

Loan Comparison Calculator

Which of two loans is cheaper overall, counting fees?

min(cost_A, cost_B)

Business & Fees

Marketplace fees, margins, landed cost

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Sales Tax / VAT Calculator

How much tax is added to a price — or included in it?

net × (1 + r)

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Etsy Fee & Profit Calculator

How much does Etsy take from a sale, and what profit is left?

price − Σ fees − cost

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Profit Margin & Markup Calculator

What is my profit margin and markup on this product?

(p − c) / p

¤Combines 3

Landed Cost Calculator (Buy from Abroad)

What will an item bought abroad really cost me, delivered — and is it cheaper than buying locally?

fx → duty → tax → Σ

Engineering

Fluids, electrical, psychrometrics

Dew Point Calculator

At what temperature will the air start to condense?

b·γ / (a − γ)

Voltage Drop Calculator

How much voltage is lost over this wire run, and is it within 3 %?

k · I · R · L

Pump Power Calculator

How much power does a pump need for this flow and head?

ρ g Q H / η

Pipe Pressure Drop Calculator

What is the friction pressure drop through this pipe?

f (L/D) ρv² / 2

W = 0.622·p_w / (p − p_w)

Psychrometric Calculator (Moist Air)

What are the wet-bulb, dew point, humidity ratio and enthalpy of this air?

Pipe Insulation Heat Loss Calculator

How much heat does this pipe lose, and how much does insulation save?

ΔT / (R_ins + 1/hA)

Engineering Unit Converter

What is this value in another unit — with a check that the units are compatible?

x · f_from / f_to

Rules & Compliance

Official rates and rule-based checks