Calcs.com for

A structural calculation API your users can defend

Add verified calculations to your software through the Calcs.com API. Results come from the same standards-aligned engine engineers already sign off on, so you ship the feature without building the engine.

Scope your integration See how it works

Request

POST/v1/projects

curl --request POST \
  --url https://api.calcs.com/v1/projects \
  --header 'Authorization: Bearer $CALCS_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
    "name": "Smith residence"
  }'

Replay of a real run. Nothing is sent from this page.

Response

Not sent

Send the request to see the response

What your user sees

Floor joist J1

2x10 D.Fir-L No. 1 · 16 in o.c. · 14 ft span · 10 psf dead, 40 psf live

Create a project, then run the calculation.

Calculation logic never stays finished

A code edition changes. Somewhere in your codebase, a hard-coded reading of the old one keeps running. Nobody notices until a user contacts you.

Years to build, never finished

Standards-checked calculation logic takes years to write. Every code update pulls your team off the roadmap and onto maintenance.

Quietly out of date

Hard-coded logic goes stale when the standard changes. Your users find out on a live project, not in a release note.

Hard to defend

When an engineer asks why a check passed, in-house logic has no path back to the clause. You have nothing to point to.

Connect once, stay current

CalcsConnect is the structural calculation API from Calcs.com, the calculation platform engineers use across the US, Canada, Australia and New Zealand. Your software calls verified calculators built to AISC, AISI, ASCE, CSA, NBCC and AS/NZS standards. When a standard changes, our engineers update the calculator, not yours.

How the calculation API works

Your product keeps its interface and its users. Calcs.com runs the calculation underneath.

Your product sends the inputs

A user draws a member, generates a layout, or runs a check. Your software passes the inputs to the API.

Floor framing

Example product, not a real app

Floor joist J1

2x8 D.Fir-L No. 1 joist, 16 in o.c.

Joist section

Fails at 122%

Live load deflection governs: L/295 against L/360.

12 x 14 ft floor bay. Joists at 16 in o.c. on two 12 ft girders. 10 psf dead, 40 psf live. Girders: 2x12.

A Calcs.com calculator applies the standard

CalcsConnect runs your inputs through the matching Calcs.com calculator.

Choose the calculator

Calcs.com

The library holds 147 calculators. Your request names the one it wants by code.

Wood Beam (ASD)timberBeamASDNDS-2024
Wood Beam (LRFD)timberBeamLRFDNDS-2024
Wood BeamtimberBeamCA
Timber BeamtimberBeamNZS3603-1993

Replay of real runs. Rows are from the live catalogue.

Your product gets the result

Formulas, assumptions, and standards references are open to inspect in Calcs.com.

Check the result

Your product

Floor joist J1

2x8 D.Fir-L No. 1 joist, 16 in o.c.

passed: false
summaryCheck: 1.220How close the governing check is to its limit (122%)
summaryCheckReferenceId: delta_ST_summaryWhich check governed: live load deflection

Re-check it by hand

Live load deflection

limit L/360 ÷ achieved L/295 = 360 ÷ 295

= 1.22againstsummaryCheck 1.220Matches

What went in

Member: 2x8 D.Fir-L No. 1 joist, 16 in o.c.
Span: 14 ft
Loads: 10 psf dead, 40 psf live
Deflection limits: L/360 live load, L/240 long-term

Open the sheet in Calcs.com to read the formulas, assumptions and references behind the live load deflection check.

Replay of a real run, trimmed for display. Nothing is sent from this page.

Give your AI a calculator, not a guess

AI models can give confident, wrong answers from engineering standards. CalcsConnect takes the math out of the model. Your AI picks the calculation and sends the inputs. A verified calculator returns the result, the same way every time. The same calls work from your product, your pipelines or your AI features.

What calls it

What Calcs.com does

Calcs.com engine

Run calculations from your product
Trigger a calc and return the result backed by the standard it was checked against, without opening Calcs.com.
Get site design data from coordinates
Drop a pin and return design values for wind, snow, seismic, and other environmental loads supported by Calcs.com.
Manage projects programmatically
Create, organize, list, and link projects so calculation work stays connected to your users' workflows.

What comes back

Your code calls the REST API

Create a project, then run a calculation with the inputs your user already has. These are the two calls from the demo above.

curl --request POST \
  --url https://api.calcs.com/v1/templates/timberBeamASDNDS-2024/calculate \
  --header 'Authorization: Bearer $CALCS_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
    "projectId": "00000000-0000-4000-8000-000000000001",
    "preset": "floorJoist",
    "name": "Floor joist J1",
    "attributes": {
      "member": "2x10 D.Fir-L No. 1",
      "L_X": 14,
      "spacing": 16
    }
  }'

Out

A solved sheet, as data

The response says whether the member passes, which check governs and by how much. Trimmed here; the full response carries every result field.

{
  "sheetId": "00000000-0000-4000-8000-000000000002",
  "templateCode": "timberBeamASDNDS-2024",
  "passed": true,
  "summaryCheck": 0.759,
  "summaryCheckReferenceId": "M_check",
  "summaryCheckError": false,
  "results": {
    "member": "2x10 D.Fir-L No. 1",
    "M_check": "1712 lb*ft / 2255 lb*ft",
    "V_check": "489 lb / 1665 lb",
    "R_check": "489 lb / 2812 lb",
    "delta_ST_summary": "-0.274 in (L/613)",
    "delta_LT_summary": "-0.317 in (L/531)",
    "...": "124 more fields"
  }
}

Validate against jobs you already ran

Run CalcsConnect on projects that have already been designed and checked. Compare the results line by line and see exactly where the numbers match.

Real projects, not demo data

Your team tests the engine on work engineers have already signed off.

Differences you can trace

Any gap points to a formula or an assumption, not a black box.

No change to your product

Your interface, users, and existing logic stay as they are while you compare.

The engine behind the API

13.5M

Calculations run on Calcs.com.

81,000

Projects run on the platform each year.

228

Calculators in the library.

Trust & quality

Why results hold up

Engineers sign off on what they can inspect. CalcsConnect runs calculators they already check and trust, so your users inherit that trust.

An allowable area check in Calcs.com beside its references panel, citing IBC 2018, 2021 and 2024 clause 506.2.1

Transparent by design

Engineers can inspect formulas, variables, and standards references before relying on a result.

A bolted plate connection in Calcs.com with its description, its AISC Steel Construction Manual reference and its checks

Maintained when standards change

Calculators are updated when codes are, so your users stay current without a release from you. See the Calcs.com quality promise.

The in-app support form in Calcs.com, with the footing calculation the question is about open beside it

Built and supported by engineers

Qualified engineers build the calculators and answer questions engineer to engineer.

Frequently asked questions

Do we have to give up our own interface?

No. Your product keeps its interface, branding, and users. Calcs.com provides the verified calculation underneath through the API.

What if we already built our own calculation logic?

Then you can test CalcsConnect against it. Run both on completed jobs and compare the results before you change anything. If they match, the real question is whether your team should keep maintaining that logic every time a code changes.

How is this different from copying standards into our code?

Copied logic has no link to the source clause and goes stale at the next edition. Calcs.com keeps calculators aligned to the standard and updates them when it changes, through controlled, licensed channels.

Can our AI features use it?

Yes. Your AI identifies which calculation applies and sends the inputs to a verified calculator. The calculator does the math, so results are repeatable and checkable. Engineers still verify outputs before relying on them.

Which standards does the API cover?

Calcs.com calculators cover AISC, AISI, ASCE, CSA, NBCC, and AS/NZS standards. Tell us which calculation your product needs and we will confirm coverage and edition before you build.

How do we get access?

Access is set up with our team, not through a self-serve sign-up. We scope your first integration together and issue keys directly.

Scope your integration

Start with one moment in your product where a result must hold up under review. We map it to calculators already in Calcs.com and run them against jobs you have completed.

Scope your integration

See how it works

Identify where your product needs a defensible result
Match it to calculators already in Calcs.com
Validate the results against completed projects

Talk with our team about connecting Calcs.com to your product. Building for manufacturers instead? See how Calcs.com puts products in the calculation.