Index figures

Reliable Indexing for Appraisals and Insurance

Lengkeek Taxaties has been providing index figures to its clients for many years. Every appraisal report must be indexed using reliable and up-to-date figures.
That is why we index appraisal reports using our own index figures. This makes sense, as we have the knowledge, experience, and data to do so with care.
Our index figures are publicly available. Anyone may use them; we appreciate it if you cite the source.

Source data and methodology

The Lengkeek index figures are based on our own valuation data;

• data from our colleagues at Lengkeek Expertises;
• additional information sources, including the Bureau for Construction Documentation (BdB).

This combination provides us with a broad and up-to-date database specifically tailored to the insurance market.

The benefits at a glance

• Always up to date – We publish new index figures monthly.
• Specific to property type – Index figures for inventory, buildings, and residential properties.
• Focused on insurability – The index figures are linked to repair costs following damage, providing a realistic and comprehensive picture of the risk.

Recent developments in construction costs (March 2026)

The construction sector is currently facing persistent cost increases.

Various publications point to structural and cyclical pressures, caused in part by:

• high energy and electricity rates;
• rising labor and installation costs;
• increasing geopolitical tensions;
• higher production costs for building materials such as steel, glass, and insulation.

Key developments:

• • Building materials: price increases averaging 3% to 5% as of January 1, 2026.
  • Installation technology: cost increases of approximately 4% to 6% (already implemented).
  • Raw materials: slight increase in wood prices, among others.
  • Underground infrastructure: 2026 indexation set at 4.48%.

In addition, tensions in the Middle East are causing a further increase in energy costs, which are passed on directly and indirectly in construction prices.

(Link to the vision document)

From Indexation to Supplementary Advice

Our standard indexation is based on actual market developments and is determined monthly on a retrospective basis.

As a result, the index closely tracks the market, but by definition has limited forward-looking capacity.

In previous phases, we recommended applying an additional economic adjustment of 7.5% to appraisals conducted for 2025, in addition to the regular indexation. This recommendation was prompted by the exceptionally strong economic rise in construction costs during the period from 2021 through 2024.

Based on the most recent market developments, we conclude that this surcharge is no longer sufficient.

Current recommendation: 10% economic surcharge

Given the ongoing uncertainties in the market and the structurally higher cost level, we now recommend applying a 10% economic surcharge on top of our regular indexation.

This recommendation replaces the previous recommendation of 7.5%.

We consider this percentage to be:

• appropriate for current market conditions;
• proportionate to the associated risk;
• necessary to prevent underinsurance and unexpected shortfalls in restoration costs.

 

2026	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	161,13	161,40
Commercial buildings	220,76	221,53
Housing	214,78	215,49

2025	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	155,35	156,38	157,18	159,99	159,99	159,99	160,17	160,66	160,66	161,13	161,13	161,13
Commercial buildings	209,72	210,23	211,09	211,16	213,33	213,51	213,82	213,95	214,33	215,24	215.39	215,66
Housing	204,18	204,68	205,22	205,52	207,20	207,34	207,96	207,96	208,02	208,54	208,76	208,87

2024	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	149,67	151.09	152.02	153.64	154.08	154.34	156.28	156.85	155.44	156,42	154,80	155,34
Commercial buildings	201,98	201,92	202.39	201.76	204.78	205.48	207.16	209.05	209.11	208,04	208,32	207,12
Housing	193,92	194,50	195.19	195.30	197.57	198.33	200.49	201.96	202.26	200,93	201,13	201,02

2023	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	145,19	147,13	147,43	149,78	150,06	149,32	151,05	151,80	150,53	151,40	149,15	149,44
Commercial buildings	198,11	200,96	202,64	203,08	203,15	202,69	203,28	203,23	202,38	200,60	200,37	199,67
Housing	190,51	192,87	193,60	193,53	192,84	192,91	194,00	193,56	193,19	193,06	192,92	192,71

2022	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	133,93	135,04	141,05	141,59	140,48	140,38	143,45	146,81	150,98	152,99	147,02	147,99
Commercial buildings	181,62	183,71	189,07	192,30	193,21	193,05	192,99	194,72	195,97	197,06	196,94	195,07
Housing	170,83	173,43	177,88	178,16	179,45	179,35	180,91	183,23	184,79	185,49	185,53	185,51

2021	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	124,47	125,93	126,31	127,32	127,51	127,69	128,50	129,18	128,98	131,00	132,08	133,33
Commercial buildings	167,97	169.19	170,21	170,73	171,44	173,14	176,14	175,63	175,95	176,49	176,68	176,79
Housing	161,24	161,36	162,04	163,46	163,80	164,89	167,03	166,36	166,64	167,11	167,26	167,61

2020	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	122,53	123,60	123,98	125,20	124,97	125,57	126,70	125,80	125,26	126,27	124,71	125,30
Commercial buildings	164,38	164,38	164,72	164,65	164,64	164,66	164,71	164,88	164,88	165,26	165,33	166,99
Housing	157,34	157,35	157,84	158,08	158,08	158,12	158,26	158,50	158,71	158,98	159,04	160,71

2019	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	120,52	122,05	122,68	124,00	123,66	123,49	124,65	125,41	124,06	124,83	123,88	124,15
Commercial buildings	161,17	161,52	161,61	161,60	162,23	162,18	163,89	163,92	163,99	164,07	163,98	164,01
Housing	153,55	153,91	154,10	154,12	155,22	155,18	156,97	156,92	157,11	157,08	157,07	157,09

2018	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	118,17	119,01	119,27	120,02	120,84	120,19	121,49	121,64	120,79	121,41	120,80	120,81
Commercial buildings	146,21	146,39	146,44	146,71	146,72	146,90	146,90	148,26	148,44	148,46	148,43	148,56
Housing	139,10	139,17	139,36	139,53	139,52	139,61	139,67	141,06	141,08	141,13	141,12	141,13

2017	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	116,44	117,54	118,06	119,13	118,60	118,23	119,20	119,41	118,91	119,16	118,69	118,60
Commercial buildings	141,71	141,73	142,19	142,51	142,55	142,53	143,24	143,33	143,71	143,88	144,50	144,51
Housing	134,68	134,72	134,93	135,14	135,16	135,15	135,86	136,03	136,27	136,39	136,72	136,78

2016	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	n.t.b.	115,62	117,33	117,46	117,74	117,09	117,44	117,64	117,22	117,64	116,88	117,18
Commercial buildings	138,06	138,20	138,30	138,14	138,76	138,88	139,36	139,39	139,40	139,44	139,73	140,03
Housing	131,25	131,23	131,38	131,62	131,91	131,97	132,69	132,72	132,73	132,77	132,95	133,02

2015	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	114,31	115,22	116,72	117,69	117,98	117,33	118,10	117,53	117,33	117,34	116,44	116,30
Commercial buildings	136,07	136,06	136,10	136,18	136,19	136,39	137,39	137,41	137,66	137,68	137,68	137,66
Housing	129,65	129,60	129,67	129,73	129,77	129,84	130,78	130,77	130,83	130,88	130,80	130,76

2014	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	115,08	115,77	117,04	117,72	117,18	116,76	117,16	117,02	116,99	116,86	116,00	115,75
Commercial buildings	135,96	135,96	135,68	135,53	135,54	135,57	135,27	135,27	135,39	135,55	135,52	135,35
Housing	129,13	129,13	129,06	128,90	128,92	128,96	129,05	129,13	129,16	129,17	129,17	129,17

2013	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory	114,17	115,34	116,88	116,97	117,02	116,44	116,85	116,60	116,70	116,40	115,71	115,81
Commercial buildings	134,09	134,09	134,16	134,60	134,61	134,06	134,14	134,07	135,13	135,19	135,14	135,19
Housing	127,07	127,21	127,53	127,81	127,76	127,68	127,77	127,70	128,27	128,47	128,39	128,46

2012	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory
Commercial buildings	132,75	132,67	132,71	132,99	133,01	132,98	132,77	133,17	133,06	133,10	133,03	132,80
Housing	126,23	126,18	126,34	126,49	126,51	126,50	126,38	126,66	126,55	126,59	126,52	126,30

2011	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory
Commercial buildings	129,51	129,88	129,86	130,61	130,78	130,71	130,88	130,88	131,00	131,18	131,18	131,18
Housing	123,78	123,89	123,94	124,35	124,60	124,61	125,00	125,00	124,88	124,94	124,94	124,97

2010	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory
Commercial buildings	124,33	124,83	125,26	126,18	126,70	126,47	126,77	126,91	127,06	127,52	127,47	127,78
Housing	120,74	120,72	120,92	121,18	121,45	121,29	121,64	121,82	122,00	122,16	122,52	122,69

2009	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory
Commercial buildings	124,66	124,86	125,03	122,41	122,77	122,89	123,09	123,10	123,06	123,42	123,38	123,50
Housing	118,56	118,26	118,98	118,71	118,98	119,05	119,09	119,50	119,45	119,93	120,06	120,09

2008	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory
Commercial buildings	119,17	120,09	120,24	121,45	121,82	122,57	123,40	124,22	123,83	123,87	123,89	124,66
Housing	114,87	115,45	115,64	115,98	116,29	116,51	117,11	117,70	117,62	117,45	117,64	118,52

2007	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory
Commercial buildings	110,70	113,49	113,70	114,13	114,17	115,06	116,36	116,36	116,46	116,41	116,46	116,45
Housing	107,88	110,42	110,59	110,81	110,91	111,16	112,65	112,65	112,53	112,95	113,00	112,99

2006	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory
Commercial buildings	106,57	106,72	106,79	106,92	107,52	107,62	108,04	108,14	108,99	109,00	109,44	109,45
Housing	104,35	104,60	104,70	104,90	105,37	105,62	105,88	106,08	107,07	107,09	107,57	107,51

2005	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory
Commercial buildings	106,33	106,22	106,28	106,51	106,24	106,47	106,53	106,62	106,98	107,03	107,11	107,11
Housing	104,16	104,32	104,41	104,46	104,38	104,11	104,45	104,46	105,01	105,03	105,04	105,04

2004	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory
Commercial buildings	101,71	102,19	102,53	103,18	103,75	104,34	105,00	105,75	105,78	106,43	106,16	105,98
Housing	101,55	102,09	102,20	102,53	103,26	103,60	103,83	104,84	104,68	104,83	104,54	104,43

2003	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Business inventory
Commercial buildings	100,00	100,06	100,11	100,46	100,30	100,22	100,90	100,75	100,77	101,30	101,32	101,32
Housing	100,00	100,01	100,08	100,25	100,10	100,11	100,62	100,42	100,42	101,07	101,08	101,08