Pricing Modifiers: How Your Final Price Is Calculated

The price you see on a hotel result in OpenBookings is rarely just the raw nightly rate multiplied by the number of nights. Rate plans can carry up to five types of pricing modifiers that adjust the total up or down depending on your booking timing, stay length, party size, and the specific days you’re staying. This guide explains every modifier type and how they interact with each other.

How modifiers are applied

When you run a search, the pricing engine processes each modifier in ascending sort_order. Modifiers that add surcharges (day-of-week, last-minute, extra-guest) are always applied. Discount modifiers (length-of-stay and early-bird) follow one rule:

Only one discount fires per booking — whichever eligible discount has the lowest sort_order wins. Any other eligible discount is skipped entirely.

This means if a rate plan offers both an early-bird discount and a length-of-stay discount, and you qualify for both, you’ll receive exactly one — the one configured with the lower sort order number. Adjustment amounts come in two forms:

Adjustment type	Meaning
`flat`	A fixed amount in the room’s currency
`percent`	A percentage of the applicable base price

For booking-level discounts (length_of_stay, early_bird), percent is calculated against the running subtotal (base prices plus any per-night surcharges already applied). For per-night modifiers (day_of_week, last_minute, extra_guest), percent is calculated against each night’s individual base_price. The total_price in every search result reflects all applied modifiers. The applied_modifiers array tells you exactly which modifier types fired.

Modifier types

Day of week
Length of stay
Early bird
Last minute
Extra guest

Day-of-week surcharge

This modifier adds a surcharge to specific days of the week — typically used to charge more for weekend nights. It fires per night independently, so only the nights that fall on a matching day of the week are affected.Trigger condition: days_of_week — an array of integers where 0 = Sunday and 6 = Saturday.

Day number	Day
0	Sunday
1	Monday
2	Tuesday
3	Wednesday
4	Thursday
5	Friday
6	Saturday

Example scenario:A room has a base price of €100/night. The rate plan includes a day-of-week modifier for days [5, 6] (Friday and Saturday) with adjustment_type: flat and adjustment_value: 30.You book Monday 3 August to Sunday 9 August (6 nights):

Night	Day	Base price	Surcharge	Night total
Mon 3 Aug	1	€100	—	€100
Tue 4 Aug	2	€100	—	€100
Wed 5 Aug	3	€100	—	€100
Thu 6 Aug	4	€100	—	€100
Fri 7 Aug	5	€100	+€30	€130
Sat 8 Aug	6	€100	+€30	€130

Subtotal: €660

Day-of-week modifiers are evaluated against the calendar date of each individual night, not the booking date.

Length-of-stay discount

This modifier gives you a discount when your stay is at least a minimum number of nights. It fires once at the booking level — not per night — and is applied as a reduction against the subtotal.Trigger condition: min_nights — the minimum stay length required to unlock the discount.This is a discount modifier. It competes with the early-bird modifier: only one discount fires per booking, determined by sort_order.Adjustment basis: For percent adjustments, the percentage is taken from the subtotal (sum of nightly base prices plus any per-night surcharges already applied). When a length-of-stay discount applies, total_price will be lower than subtotal.Example scenario:A room has a base price of €150/night. The rate plan includes a length-of-stay modifier with min_nights: 5, adjustment_type: percent, adjustment_value: -10 (a 10% discount).You book a 7-night stay:

subtotal = 7 × €150 = €1,050

discount = (1,050 × −10) / 100 = −€105

total_price = €1,050 − €105 = €945

If you booked only 4 nights, min_nights: 5 would not be met, the modifier would not fire, and you’d pay the full €600.

When you see "length_of_stay" in a result’s applied_modifiers array, the long-stay discount fired and your total_price is already lower than subtotal.

Early-bird discount

This modifier rewards you for booking well in advance. It fires once at the booking level when the number of days between today and your arrival date meets or exceeds the configured threshold.Trigger condition: days_before_arrival — the minimum number of days in advance you must book.

daysUntilArrival = (arrivalDate − today) / 86,400,000 ms

The modifier fires when daysUntilArrival ≥ days_before_arrival.This is a discount modifier. It competes with the length-of-stay modifier: only one discount fires per booking, determined by sort_order.Adjustment basis: For percent adjustments, the percentage is taken from the subtotal.Example scenario:A room has a base price of €200/night. The rate plan includes an early-bird modifier with days_before_arrival: 30, adjustment_type: flat, adjustment_value: -50.Today is 1 July and your arrival is 15 August (45 days away):

daysUntilArrival = 45 ≥ 30 → modifier fires

subtotal (3 nights) = 3 × €200 = €600
discount = −€50

total_price = €600 − €50 = €550

If you tried to book the same room on 20 July for a 15 August arrival (25 days away), 25 < 30 means the modifier would not fire and you’d pay €600.

Early-bird eligibility is evaluated at search time using today’s date. The price shown in results reflects whether you currently qualify — it won’t change retroactively if you wait to confirm.

Last-minute surcharge

This modifier adds a surcharge when you book close to your arrival date. Unlike the early-bird discount, this one increases your price — it fires when daysUntilArrival is at or below the configured threshold.Trigger condition: days_till_arrival — the maximum number of days before arrival that triggers the surcharge.

daysUntilArrival = (arrivalDate − today) / 86,400,000 ms

The modifier fires when daysUntilArrival ≤ days_till_arrival.This is a surcharge modifier — it is not subject to the one-discount-per-booking rule and applies on top of any other modifiers.Adjustment basis: The surcharge is applied to each night individually. For percent adjustments, the percentage is taken from each night’s base_price.Example scenario:A room has a base price of €120/night. The rate plan includes a last-minute modifier with days_till_arrival: 3, adjustment_type: percent, adjustment_value: 20.Today is 12 August and your arrival is 14 August (2 days away):

daysUntilArrival = 2 ≤ 3 → modifier fires

surcharge per night = (120 × 20) / 100 = €24
2-night stay surcharge = 2 × €24 = €48

subtotal (base) = 2 × €120 = €240
total_price = €240 + €48 = €288

Last-minute surcharges can significantly increase the price for same-day or next-day bookings. The total_price in results always includes this surcharge if it applies to your booking date.

Extra-guest surcharge

This modifier adds a surcharge for each guest above a room’s base_occupancy. It fires when (adults + children) > base_occupancy, and is applied night by night across the full stay.Trigger condition: guests_above_base — the threshold above which extra guests are counted.

extraGuests = max(0, (adults + children) − base_occupancy)

The modifier fires when extraGuests > guests_above_base (typically guests_above_base is set to match base_occupancy, so any guest above the base count triggers it).This is a surcharge modifier — it applies on top of discounts and is not subject to the one-discount rule.Adjustment basis: The surcharge scales with the number of extra guests. For flat adjustments, the amount is multiplied by extraGuests per night. For percent, the percentage of base_price is multiplied by extraGuests per night.

Adjustment type	Per-night surcharge formula
`flat`	`adjustment_value × extraGuests`
`percent`	`(base_price × adjustment_value × extraGuests) / 100`

Example scenario — flat surcharge:A room has base_occupancy: 1, base price €100/night. The modifier has adjustment_type: flat, adjustment_value: 25.You search for 2 adults, 1 child (3 total), 3-night stay:

extraGuests = max(0, 3 − 1) = 2

surcharge per night = 25 × 2 = €50
total surcharge = €50 × 3 nights = €150

subtotal (base) = 3 × €100 = €300
total_price = €300 + €150 = €450

Example scenario — percent surcharge:Same room, but adjustment_type: percent, adjustment_value: 10. Same party and stay:

surcharge per night = (100 × 10 × 2) / 100 = €20
total surcharge = €20 × 3 = €60

total_price = €300 + €60 = €360

See the guest management guide for a full explanation of how base_occupancy, max_adults, and max_children interact.

Modifier interaction: discount priority

When a rate plan has both a length_of_stay and an early_bird modifier and you qualify for both, only one fires. The engine processes modifiers in ascending sort_order and skips any second discount type once a discount has already been applied. Example:

`sort_order`	Type	Trigger	Discount
1	`early_bird`	Book 30+ days ahead	−10%
2	`length_of_stay`	Stay 7+ nights	−5%

You book 40 days in advance for a 10-night stay — you qualify for both. Because early_bird has sort_order: 1, it fires first. The engine then skips length_of_stay since a discount has already been applied. You receive the early-bird discount only. Reverse the sort order numbers and the length-of-stay discount would win instead.

Surcharge modifiers (day_of_week, last_minute, extra_guest) are never skipped. The one-discount rule applies exclusively to length_of_stay and early_bird.

Summary reference

day_of_week

Type: Surcharge | Scope: Per nightAdds a surcharge to specific days of the week. Evaluated against the calendar date of each individual night.Trigger field: days_of_week (array of integers, 0 = Sunday, 6 = Saturday)

length_of_stay

Type: Discount | Scope: Booking levelReduces total price when the stay meets a minimum night count. Applied against subtotal. Subject to the one-discount-per-booking rule.Trigger field: min_nights

early_bird

Type: Discount | Scope: Booking levelReduces total price when you book far enough in advance. Applied against subtotal. Subject to the one-discount-per-booking rule.Trigger field: days_before_arrival

last_minute

Type: Surcharge | Scope: Per nightAdds a surcharge when you book close to arrival. Applied per night against each night’s base_price. Always fires if eligible — not subject to the discount rule.Trigger field: days_till_arrival

extra_guest

Type: Surcharge | Scope: Per night × extra guestsAdds a per-night surcharge for each guest above base_occupancy. Scales with the number of extra guests. Always fires if eligible — not subject to the discount rule.Trigger field: guests_above_base

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Core Features

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Configuration

Help

Pricing Modifiers: How Your Final Price Is Calculated

How modifiers are applied

Modifier types

Day-of-week surcharge

Length-of-stay discount

Early-bird discount

Last-minute surcharge

Extra-guest surcharge

Modifier interaction: discount priority

Summary reference

Get Started

Core Features

Guides

Configuration

Help

​How modifiers are applied

​Modifier types

​Day-of-week surcharge

​Length-of-stay discount

​Early-bird discount

​Last-minute surcharge

​Extra-guest surcharge

​Modifier interaction: discount priority

​Summary reference

How modifiers are applied

Modifier types

Day-of-week surcharge

Length-of-stay discount

Early-bird discount

Last-minute surcharge

Extra-guest surcharge

Modifier interaction: discount priority

Summary reference