Position Sizing
Ratio and fixed sizing work the same way on the Tradovate Copier, including the point above about replacements not changing quantity, and it carries fractional remainders like NT8 does. Two differences are worth knowing. Tradovate's carry is signed and tracked per copier, leader, and contract, so it applies to entries and exits in both directions rather than exits only, and if that carry state cannot be read safely the follower placement is withheld rather than guessed. And the Tradovate maximum is Max qty per copy, which caps each individual signal order or execution fill rather than the follower's total position. See Tradovate Copier.
Ratio sizing
Set a follower's size as a multiple of the leader's: 0.5 halves it, 2 doubles it. Decimal ratios are supported.
The follower quantity is rounded down, then floored at one contract:
followerQty = floor(leaderQty × ratio)
if followerQty < 1 then followerQty = 1
So at 0.5×, a 3-contract leader entry copies as 1 contract, and a 1-contract leader entry still copies as 1. A follower never sits out an entry because the maths rounded it to zero.
Fixed sizing
Instead of a ratio, pin the follower to a constant quantity regardless of what the leader traded. Useful when the follower has its own risk budget that has nothing to do with the leader's sizing.
What happens to the fraction on exits
Rounding down on every fill would leak contracts. Close a 23-contract position at 0.5× in two pieces and naive flooring gives you 11 then 1, leaving the follower holding 1 contract after the leader is flat.
The copier avoids this by carrying the remainder. Each exit fill adds the leftover fraction from the previous one before rounding:
| Leader exit | Raw follower qty | Carried in | Sent | Remainder kept |
|---|---|---|---|---|
| 23 | 11.5 | 0.0 | 11 | 0.5 |
| 3 | 1.5 | 0.5 | 2 | 0.0 |
That is 13 contracts closed against a 13-contract follower position, not 12. The remainder is tracked per copier, leader, follower, and instrument, and two guards apply: the copier never closes more than the follower actually holds, and the carry resets when the position is flat.
The practical consequence is that scaled exits converge to flat. You do not need to square up a follower by hand after a multi-stage close.
Maximum position size
The maximum is a ceiling on the follower's total position, not on any single order. Before copying, the copier adds the incoming quantity to the follower's current signed position, and if the result would exceed the maximum it skips the order and logs why. An order that would take the follower only part of the way is clamped down to the maximum instead.
This is what makes it a real risk control: the follower cannot be walked past the ceiling by a series of small entries, however large the leader gets.
Contract size mapping
Swapping a leader contract for a related one is a separate setting from sizing, and the two do not talk to each other: a replacement changes which contract the follower trades, while ratio and fixed quantity decide how many. Mapping ES to MES at ratio 1 sends the follower the same number of contracts on the micro.
If you want the micro position to carry comparable exposure, set the ratio to match the contract-size difference. ES to MES at ratio 10 is the usual pairing, since MES is a tenth the size. See Instrument Filtering and Replacement.
