Shorten Building Time is the first half of a Ikariam Plus feature that will shorten the normal build time of any building level for a fee which is only payable using Ambrosia.

This feature has a 2 click process.
  1. The first click, Shorten Building Time, will reduce the normal build Time small for that building level by ½.
  2. The second click, Complete Instantly, will complete the building level.
    If more than ½ of the original build time has already been completed by the time you make your first click then the first click will complete the building level (Complete Instantly).
The exceptions to the buildings which can use this feature are the Palace and the Governor's Residences.

With patch 0.6.5 it became free to use when the building has less than 5 minutes remaining.

Ambrosia cost

For every 30 minutes of build time you will pay and additional 2 Ambrosia with a cap at 74 Ambrosia

From (Min) To (Max) Cost in Ambrosia
0s 5m 0
5m 1s 29m 59s 2
30m 0s 59m 59s 7
1h 0m 0s 1h 29m 59s 6
1h 30m 0s 1h 59m 59s 8
2h 0m 0s 2h 29m 59s 10
2h 30m 0s 2h 59m 59s 12
3h 0m 0s 3h 29m 59s 14
3h 30m 0s 3h 59m 59s 16
4h 0m 0s 4h 29m 59s 18
4h 30m 0s 4h 59m 59s 20
5h 0m 0s 5h 29m 59s 22
5h 30m 0s 5h 59m 59s 24
6h 0m 0s 6h 29m 59s 26
6h 30m 0s 6h 59m 59s 28
7h 0m 0s 7h 29m 59s 30
7h 30m 0s 7h 59m 59s 32
8h 0m 0s 8h 29m 59s 34
8h 30m 0s 8h 59m 59s 36
From (Min) To (Max) Cost in Ambrosia
9h 0m 0s 9h 29m 59s 38
9h 30m 0s 9h 59m 59s 40
10h 0m 0s 10h 29m 59s 42
10h 30m 0s 10h 59m 59s 44
11h 0m 0s 11h 29m 59s 46
11h 30m 0s 11h 59m 59s 48
12h 0m 0s 12h 29m 59s 50
12h 30m 0s 12h 59m 59s 52
13h 0m 0s 13h 29m 59s 54
13h 30m 0s 13h 59m 59s 56
14h 0m 0s 14h 29m 59s 58
14h 30m 0s 14h 59m 59s 60
15h 0m 0s 15h 29m 59s 62
15h 30m 0s 15h 59m 59s 64
16h 0m 0s 16h 29m 59s 66
16h 30m 0s 16h 59m 59s 68
17h 0m 0s 17h 29m 59s 70
17h 30m 0s 17h 59m 59s 72
18h 0m 0s I N F I N I T Y 74