# What are the SDR/NDR model output units? **URL:** \ **Category:** Software Support\ **Tags:** sdr, ndr\ **Created:** [January 23, 2026, 5:08am UTC](https://community.naturalcapitalalliance.org/t/what-are-the-sdr-ndr-model-output-units/6330 "2026-01-23T05:08:05Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![tharindu\_bawantha](https://avatars.discourse-cdn.com/v4/letter/t/ecc23a/32.png) [@tharindu\_bawantha](https://community.naturalcapitalalliance.org/u/tharindu_bawantha)\ **Post date:** [January 23, 2026, 5:08am UTC](https://community.naturalcapitalalliance.org/t/what-are-the-sdr-ndr-model-output-units/6330/1 "2026-01-23T05:08:05Z")
#### Hello everyone, I’m currently working with the SDR and NDR models using a 30m × 30m SRTM DEM. I have a question about interpreting and converting the output units. According to the InVEST User Guide, the model outputs are in metric tons/hectare/year. My outputs maintain the same 30m × 30m resolution as my input DEM Since each pixel represents 900 m² (30m × 30m = 0.09 hectares), and the outputs are already given in tons/hectare/year, do I need to convert these values to get the total sediment/nutrient load per pixel? How can i do such conversion? I want to ensure I’m correctly interpreting the outputs before proceeding with my analysis. Thank you in advance for your help! ### ---
**Author:** ![megannissel](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.naturalcapitalalliance.org/megannissel/32/3547_2.png) [@megannissel](https://community.naturalcapitalalliance.org/u/megannissel)\ **Post date:** [January 23, 2026, 8:41pm UTC](https://community.naturalcapitalalliance.org/t/what-are-the-sdr-ndr-model-output-units/6330/2 "2026-01-23T20:41:08Z")
Hi @tharindu_bawantha, Since the raster results are given in metric tons/hectare/year, to convert the per hectare values to per pixel values, you need to adjust by the size of your pixels relative to one hectare. For example: If 1 pixel = 900 m2 (as yours do, with a 30m x 30m resolution), then the conversion from metric tons per hectare (t/ha) to metric tons per pixel (t/pixel) would be: (t/ha x 1/10000 ha/m2 x 900 m2/pixel) or (the per hectare value x (900/10000)). The number will get smaller when the pixel size is smaller than a hectare. ---
**Author:** ![tharindu\_bawantha](https://avatars.discourse-cdn.com/v4/letter/t/ecc23a/32.png) [@tharindu\_bawantha](https://community.naturalcapitalalliance.org/u/tharindu_bawantha)\ **Post date:** [January 24, 2026, 3:21pm UTC](https://community.naturalcapitalalliance.org/t/what-are-the-sdr-ndr-model-output-units/6330/3 "2026-01-24T15:21:34Z")
Thank you for your valuble solution. So, After this conversion, the final units of the soil erosion came as t/pixel/year or t/ha/year? I need the data as in the t/ha/yr units. ---
**Author:** ![megannissel](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.naturalcapitalalliance.org/megannissel/32/3547_2.png) [@megannissel](https://community.naturalcapitalalliance.org/u/megannissel)\ **Post date:** [January 26, 2026, 1:45pm UTC](https://community.naturalcapitalalliance.org/t/what-are-the-sdr-ndr-model-output-units/6330/4 "2026-01-26T13:45:52Z")
As long as you’re using a version of InVEST \>= 3.15.0, the SDR and NDR raster outputs are already given in t/ha/year. The conversion is only necessary if you want to instead get values in t/pixel/year. ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex031/uploads/naturalcapitalproject/original/2X/8/8d95591aa074da87ea0fdd61ca47c1c3c0588aa7.png) [@system](https://community.naturalcapitalalliance.org/u/system)\ **Post date:** [April 26, 2026, 1:46pm UTC](https://community.naturalcapitalalliance.org/t/what-are-the-sdr-ndr-model-output-units/6330/5 "2026-04-26T13:46:18Z")
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