Rounding Calculator — Compare 6 Rounding Methods
Round by place value without guessing how .5 ties or negative numbers are handled.
Rounding receipt
One decimal, six explicit rules
Enter the number once and compare nearest-half, directed, and truncation rules without reopening settings. The result cards name the direction used, while the receipt shows the target place, discarded digits, exact-tie status, and two neighboring rounded values.
Negative numbers make names matter
| Method at -8.5 | Whole-number result |
|---|---|
| Half away from zero | -9 |
| Half toward zero | -8 |
| Half to even | -8 |
| Ceiling (+∞) | -8 |
| Floor (−∞) | -9 |
| Toward zero | -8 |
Exact decimal digits, not binary guesses
The calculation never converts the input to JavaScript Number. It uses the typed digits and integer arithmetic to determine whether the discarded part is below, above, or exactly halfway. Inputs are intentionally bounded to one plain decimal, 40 whole digits, 30 fractional digits, and places from millions through 12 decimal places.
Frequently asked questions
How do you round -8.5?
It depends on the tie rule. Half away from zero and floor give -9; half toward zero, half to even, ceiling, and truncation give -8. This calculator labels every rule instead of calling one of them simply 'normal rounding.'
What is half-even rounding?
Half-even chooses the nearest value normally. At an exact halfway tie, it chooses the neighbor whose retained digit is even. Thus 2.5 becomes 2, 3.5 becomes 4, and -8.5 becomes -8 when rounding to a whole number.
How do I round to the nearest tenth?
Choose 1 decimal place. The hundredths digit and everything after it form the discarded part. If that part is less than half, keep the tenths digit; if greater than half, increase its magnitude; at exactly half, use the selected tie rule.
Why can 1.005 be rounded incorrectly by software?
Binary floating-point cannot store every decimal exactly. This page reads the decimal as a string and compares integer digits, so 1.005 is recognized as an exact tie at two decimal places.
Does this calculator accept scientific notation?
No. Enter one plain decimal without commas or an exponent. This keeps every accepted digit explicit and makes the rounding receipt auditable.