Spreadsheet calculators and planning tools

Free calculators and planning helpers for founders and finance teams who live in Google Sheets and Excel. When you need full statements, jump to our templates.

Explore spreadsheet templates for full workbooks, or open the Lexicon for clear definitions of the terms behind the math.

Built for real spreadsheet work

Search or filter to match the job in front of you—percentages and growth, descriptive stats, loan schedules, time and hours, retirement checks, currency reference rates, and more. Most tools include copy-ready Google Sheets and Excel snippets; finance results are illustrations, not advice.

Spreadsheet mathLive
Percentage calculator
Percent of a number, share as a percent, reverse the implied whole, and increase or decrease one value—plus copy-ready Sheets and Excel formulas.
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Spreadsheet mathLive
Compound interest calculator
Starting balance, monthly contributions, compounding, and nominal rate—ending balance, totals, and copy-ready FV formulas.
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Spreadsheet mathLive
Simple interest calculator
Principal, annual percent rate, and time in years plus months—total simple interest and ending balance with I = Prt and Sheets/Excel cells.
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Spreadsheet mathLive
Future value calculator
Present value, optional end-of-month contributions, nominal rate, horizon, and compounding—future value, totals, interest, and FV-style Sheets/Excel snippets.
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Spreadsheet mathLive
Exponent calculator (powers)
a^b and e^x in double precision with spreadsheet parity (POWER, EXP) and clear errors when no real result—educational, not a symbolic algebra app.
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Spreadsheet mathLive
Scientific notation calculator
Decimals, E-notation, and m×10^n → plain decimal, canonical scientific, engineering, and copy-ready E-string—double-precision like Sheets/Excel; not a graphing scientific calculator.
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Spreadsheet mathLive
Log calculator (logarithm)
Log base 10, e, 2, or custom: y = log_b(x) and antilog x = b^y with domain checks; LOG, LN, LOG10, POWER patterns for Google Sheets and Excel.
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PlanningLive
Time calculator
Duration between two date-times, shift a meeting by days or hours, and add or subtract clock-style durations—with Sheets and Excel patterns.
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PlanningLive
Amortization schedule calculator
Fixed-rate loan: monthly payment, principal and interest over time, full schedule—with PMT, PPMT, and IPMT for Sheets and Excel.
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Unit economicsLive
Currency converter
Convert amounts with ECB-oriented reference rates, optional historical table date, inverse rate, and spreadsheet tips for Sheets and Excel—not a bank trading quote.
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Unit economicsLive
Tip calculator
Bill, tip percent, and party size—tip amount, grand total, and equal per-person lines. Transparent math for dining out; not tax or payroll software.
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Unit economicsLive
Net Promoter Score (NPS) calculator
0–10 recommendation counts: promoters, passives, and detractors—NPS as % promoters minus % detractors. For customer loyalty, not national pension; educational only.
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PlanningLive
Retirement savings calculator
Ages, savings, monthly contribution, and rate—project your nest egg at retirement or back-solve a monthly target; FV/PMT patterns and optional “today’s dollars” view—illustration only, not advice.
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PlanningLive
College savings calculator
Child or student age, first college year, current savings, return, and compounding—project a balance or back-solve a monthly to a goal; FV/PMT for Sheets/Excel—no 529, aid, or tax rules.
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PlanningLive
Student loan calculator
Fixed-rate student loan in repayment: balance, nominal APR, remaining term—monthly PMT, total interest, total repaid. Optional extra to principal; early payoff vs baseline. Not federal IDR/SAVE; PMT/Sheets patterns—not a servicer quote.
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PlanningLive
Mortgage payment calculator
Fixed-rate P&I from loan amount or home price and down payment; optional monthly tax, insurance, HOA, and PMI estimates; PMT for Sheets/Excel—not a lender quote.
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PlanningLive
Property tax calculator
Taxable base × effective annual rate you enter (or implied % from known annual tax); optional market × assessment ratio; annual and monthly; Sheets/Excel—not county lookup or tax advice.
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PlanningLive
Debt-to-income calculator
Gross monthly income, housing costs, and recurring debts → front-end and back-end DTI %; SUM patterns for Sheets/Excel—not a credit decision.
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PlanningLive
Time card calculator
Weekly clock in and out, unpaid breaks, hours:minutes and decimal-hour totals, optional gross pay line—Sheets and Excel patterns; not payroll software.
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PlanningLive
Work time calculator
One shift: clock in, clock out, unpaid break—net hours in hours:minutes and decimal hours; optional gross illustration—Sheets/Excel tips; not payroll software.
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