Free online tools · verified math
Calculators that show their work.
Every result on TrueSums comes with the formula it used, the sources behind it, and the date the data was checked. No black boxes.
Try it — the work stays on the tape
Tape
Start typing. Every step stays here so you can read the work back — and copy it.
Adds left to right, like a paper tape — so 2 + 3 × 4 is 20, not 14.
Browse by category
Money & Finance
Budgets, rates, and payoff plans — with every formula cited.
9 tools
Health & Fitness
Planning and estimation tools. Not medical advice — sources included.
First tools shipping now
Converters & Scalers
Specialized conversions where one number is never enough.
1 tool
Planners & Generators
Schedules, quantities, and printable plans built from your inputs.
First tools shipping now
Tools by Profession
Built for the math a specific job actually runs into.
First tools shipping now
The TrueSums standard
Formula cited
Every calculation names its method and links the source it came from.
Tested against known answers
Each tool must reproduce five published test cases before it ships.
Dated data
Anything that changes — rates, limits, guidelines — shows when we last checked it.