Developer Calculator - Expressions & Variables
Run expressions line by line, reuse named variables, and keep your calculation history on this device.
Supported operations
Powered by expr-eval, this calculator handles everyday math expressions, variables, arrays, and functions.
2 + 3 * 4 Basic arithmetic
(2 + 3) * 4 Parentheses
2^8 Powers
10! Factorial
10 % 3 Remainder / modulo
sqrt(16) Square root
cbrt(27) Cube root
abs(-5), round(3.6) Number helpers
sum(3, 5, 7), avg(3, 5, 7) Sum & average
min(3, 8, 1), max(3, 8, 1) Min / max
sin(PI / 2), log10(100) Trig & logs
x = 42 Variables
Quick Start for the Developer Calculator
Keep related calculations together with expressions, variables, and local history.
Enter an expression
Type arithmetic, powers, arrays, or function calls into the prompt, then evaluate each line as you work.
Save reusable variables
Assign values with name = value so later expressions can reference the same numbers without retyping them.
Restore local history
Reopen the page to continue from the calculation log and variables saved locally in IndexedDB.
Built for Developer Calculations
Use it for quick technical math where intermediate values, reusable variables, and privacy all matter.
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REPL-style calculation
Each line is evaluated separately, so you can keep a readable trail of results instead of overwriting one answer at a time.
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Variables, functions, and arrays
Use named variables, PI / E constants, arrays, and built-in functions such as pow, mod, min, and max.
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Local session history
IndexedDB keeps calculator sessions on your device, so you can reopen prior calculations without sending them to a server.
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Private browser execution
Expressions are parsed and evaluated in the browser. ViewJSON does not need to upload your formulas, variables, or results.
When a simple calculator is not enough
Use it for engineering checks, API cost math, configuration values, and data-size calculations where intermediate results matter.
API cost estimates
Store token counts, unit prices, or request volume as variables and adjust them line by line.
Data size checks
Compare bytes, kilobytes, ratios, and batch sizes while every intermediate result stays visible.
Configuration math
Calculate limits, timeouts, ratios, thresholds, and capacity numbers without leaving the browser.
Repeatable calculation notes
Keep a small calculation trail you can restore later when the same debugging task comes back.
Developer Calculator FAQ
Practical answers about syntax, privacy, history, and how this calculator differs from a classic programmer calculator.
What is a developer calculator?
A developer calculator is a browser-based tool for expression evaluation, named variables, built-in functions, and local calculation history.
Does the developer calculator upload my expressions or results?
No. Expressions, variables, and results are evaluated in your browser. Session history is stored locally in IndexedDB on your device.
What syntax does the developer calculator support?
The developer calculator supports arithmetic expressions, ^ powers, [] arrays, named assignments, PI / E constants, and functions such as pow, mod, min, and max.
Can I reuse variables in the developer calculator?
Yes. Assign a value with name = value, then reuse that variable in later expressions during the same calculator session.
Is this the same as a programmer calculator?
Not exactly. This developer calculator focuses on expressions, variables, functions, and local history. A classic programmer calculator usually focuses on binary, hexadecimal, and bitwise operations.