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The Last Decimal / The bonus
The credit and the wagering

The bonus: the credit and the wagering

A bonus is rounded twice before it is used: once when the credit is calculated and again on every contribution toward the wagering requirement. This page follows eight deposits through both roundings.

Sample spec
deposits
8
deposited
836.22
credited
782.00
rounding gap
4.22
the unitThe smallest amount the currency can express. In a two-decimal currency it is 0.01; the increment a stake must take is coarser and published per market.
the directionWhich way each rounding goes: down on a stake and a return, up on a duty and down on a prize. It is a rule, published, and it decides who keeps the fraction.
the volumeOne unit per event is nothing once and a figure at scale: on the samples, two thousand events of the same size retain 60.00 from the digits alone.
Direct answer

A bonus credit is calculated as a percentage of the deposit and then rounded down to a unit the operator chooses, usually the whole currency unit, and capped. On eight invented deposits totalling 836.22, the credit came to 782.00: 50.00 of the gap was the cap and 4.22 was the rounding, and one deposit of 0.99 credited nothing.

Eight deposits, two roundings

The first rounding decides how much bonus exists; the second decides how much of each bet counts toward releasing it. Both are published, and both move the arithmetic away from the headline percentage.

Sample E - eight deposits against a 100% credit rounded down to the whole unit, capped at 200.00
DepositCreditRoundingNote
49.5049.000.50rounded down
100.00100.000.00exact
0.990.000.99credits nothing
25.7525.000.75rounded down
199.99199.000.99rounded down
200.00200.000.00at the cap
250.00200.0050.00cap bites
9.999.000.99rounded down
836.22782.0054.2250.00 cap + 4.22 rounding
sample E - separating the cap from the rounding total deposited = 836.22 ; total credited = 782.00 gap = 836.22 - 782.00 = 54.22 of that gap: rounding = 0.50 + 0.99 + 0.75 + 0.99 + 0.99 + 0.00 = 4.22 and the cap = 250.00 - 200.00 = 50.00 4.22 + 50.00 = 54.22 ✓ - so 92% of the headline gap is the cap, and the rounding accounts for the other 8%.

Then the wagering is rounded too

The credit is not the end of it. The wagering requirement is calculated on the rounded credit, and each qualifying bet contributes only a rounded share. On the sample the credit of 49.00 carries a 35-times requirement, and the arithmetic happens on the credited figure rather than on the deposit.

the wagering built on a rounded credit deposit 49.50 → credit rounded down 49.00 (0.50 withheld) requirement 35 × 49.00 = 1,715.00 had the credit been 50.00: 35 × 50.00 = 1,750.00 → 35.00 more to wager so the 0.50 withheld by the rounding also removes 35.00 of wagering, and with it 35.00 of the expected cost the player would have run up clearing it.

That last line is the point of the page, and it cuts both ways. A rounding that reduces a credit reduces the amount that has to be wagered, and a wagering requirement is itself a cost: the arithmetic is not simply "less bonus is worse". What the rounding does is make the offer's published percentage untrue at the level of the single deposit, and the cap untrue at the level of the larger one, and both of those are decided by numbers printed in the terms rather than by chance.

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