ProRealAlgos
Mathematical/probuilder · probacktest · proorder · proscreener

ROUND

ROUND in ProBuilder rounds a number to the nearest integer, or to a set number of decimal places. Syntax, the banker's rounding note and worked examples.

Syntax

probuilder
ROUND(a, digits)

Parameters

NameTypeDescription
anumberThe value to round.
digitsintegerOptional. Number of decimal places to round to. When omitted, a is rounded to the nearest whole number.

Formula

code
ROUND(x) = nearest integer to x,   halves rounded to the nearest even value

With digits, a is rounded to that many decimal places, so ROUND(3.14159, 2) returns 3.14.

How it works

ROUND chooses the nearest value in either direction, unlike CEIL which always rounds up and FLOOR which always rounds down. A fractional part below 0.5 rounds down, above 0.5 rounds up. Exact halves follow banker's rounding: they go to the nearest even number, so ROUND(2.5) gives 2 and ROUND(3.5) gives 4. This reduces cumulative bias when rounding many values.

The optional digits argument sets the precision of the result, useful for normalizing prices or indicator readings to a fixed number of decimals.

Examples

Example 1, Round a rate of change (Indicator)

probuilder
// Round the 10-period rate of change to a whole number
i1 = ROC[10](close)
roundedROCvalue = ROUND(i1)
RETURN i1 AS "ROC", roundedROCvalue AS "ROC rounded"

If the raw reading is 9.6, ROUND returns 10. A reading of 9.4 would round down to 9.

Example 2, Round to two decimals for grouping (ProScreener)

probuilder
// Group instruments by a two-decimal ratio
ratio = close / Average[50](close)
r = ROUND(ratio, 2)
SCREENER[r >= 1](r AS "Ratio 2dp")

Rounding to two decimals collapses near-identical ratios into shared buckets.

Example 3, Round a computed target price (ProOrder)

probuilder
// Round a target price to a whole number before display
entry = close
target = ROUND(entry * 1.015)
IF NOT LongOnMarket AND close CROSSES OVER Average[20](close) THEN
  BUY 1 CONTRACT AT MARKET
ENDIF

ROUND normalizes the computed target to a whole number. To snap an order price to a valid tick instead, use ROUNDEDUP or ROUNDEDDOWN.

Common errors and gotchas

  • Halves round to even. ROUND(2.5) returns 2, not 3, because banker's rounding sends exact halves to the nearest even number. Do not assume 0.5 always rounds up.
  • Rounds both directions. Unlike CEIL and FLOOR, ROUND can go up or down. Use CEIL to force upward and FLOOR to force downward.
  • Not tick rounding. ROUND works on integers and decimals. To round an order price to the instrument's tradable tick, use ROUNDEDUP or ROUNDEDDOWN.
  • CEIL, rounds up to the nearest integer or decimal.
  • FLOOR, rounds down to the nearest integer or decimal.
  • ROUNDEDUP, rounds an order price up to the nearest tradable tick.
  • ROUNDEDDOWN, rounds an order price down to the nearest tradable tick.
  • ABS, absolute value, often paired with rounding.
  • SGN, sign of a value.
  • MOD, remainder of a division.