> For the complete documentation index, see [llms.txt](/llms.txt). [miniwebtool /api](/) [tools](/tools/) [docs](/docs/) [reference](/v1/docs) [pricing](/#pricing) [log in](/dashboard/login/) [get free key →](/billing/checkout/?plan=free) - [~](/) - / - [tools](/tools/) - / - [finance](/tools/#finance) - / - Future Value Calculator API # Future Value Calculator API finance 2 credits / call v2026-04-22 Calculate future value from a lump sum plus optional recurring contributions. One POST adds Future Value Calculator to your app, site, workflow, or agent — formula, validation, edge cases, and docs already handled. prefer a UI? [Open the Future Value Calculator on miniwebtool.com →](https://miniwebtool.com/future-value-calculator/) [Start Starter →](/billing/checkout/?plan=starter) Requires Starter+ · $29/mo Starts on Starter Free keys can view docs and examples, but calls to this endpoint require Starter or higher. [Start Starter →](/billing/checkout/?plan=starter) ### Endpoint POST · 2cr ```text POST https://api.miniwebtool.com/v1/tools/future-value-calculator/run ``` ### Request body Field Type Req. `present_value` `float` ✓ `annual_rate_percent` `float` ✓ `years` `float` ✓ `compound_frequency` annually | semiannually | quarterly | monthly | daily `str` — `contribution` `float` — `contribution_frequency` annually | quarterly | monthly `str` — `precision` `int` — ### Cost & access - 2 credits per successful call — failed calls refund. - Starts on: Starter or higher. - Max payload:`65536`bytes. - Privacy mode:`hash_only` - Available on: starter, pro, business, scale ### Response envelope ```text { "request_id": "01K...", "tool": "future-value-calculator", "tool_version": "2026-04-22", "credits_used": 2, "result": {... } } ``` ### Try it API key * Stored only in this browser tab. Playground test key is prefilled and only works on this page. [Get a live key →](/billing/checkout/?plan=starter) present_value (float) * annual_rate_percent (float) * years (float) * compound_frequency (str) annually semiannually quarterly monthly daily annually | semiannually | quarterly | monthly | daily contribution (float) contribution_frequency (str) annually quarterly monthly annually | quarterly | monthly precision (int) Send request → Response copy body This endpoint starts on Starter Your key is valid, but its current plan cannot call`future-value-calculator`. Upgrade to Starter or higher to run this tool. [Start Starter →](/billing/checkout/?plan=starter) [Compare plans](/#pricing) ```text ``` Response headers ```text ``` ### Code examples cURL Python JavaScript PHP Ruby Go Java copy ```text curl -X POST https://api.miniwebtool.com/v1/tools/future-value-calculator/run \ -H 'Authorization: Bearer mwt_live_YOUR_KEY' \ -H 'Content-Type: application/json' \ -d '{"present_value":10000,"annual_rate_percent":7,"years":10,"compound_frequency":"monthly","contribution":100,"contribution_frequency":"monthly"}' ``` copy ```text import requests resp = requests.post( 'https://api.miniwebtool.com/v1/tools/future-value-calculator/run', headers={'Authorization': 'Bearer mwt_live_YOUR_KEY'}, json={'present_value': 10000, 'annual_rate_percent': 7, 'years': 10, 'compound_frequency': 'monthly', 'contribution': 100, 'contribution_frequency': 'monthly'}, ) resp.raise_for_status() print(resp.json()) ``` copy ```text const resp = await fetch( 'https://api.miniwebtool.com/v1/tools/future-value-calculator/run', { method: 'POST', headers: { 'Authorization': 'Bearer mwt_live_YOUR_KEY', 'Content-Type': 'application/json', }, body: JSON.stringify({"present_value":10000,"annual_rate_percent":7,"years":10,"compound_frequency":"monthly","contribution":100,"contribution_frequency":"monthly"}), } ); const data = await resp.json(); console.log(data); ``` copy ```text true, CURLOPT_RETURNTRANSFER => true, CURLOPT_HTTPHEADER => [ 'Authorization: Bearer mwt_live_YOUR_KEY', 'Content-Type: application/json', ], CURLOPT_POSTFIELDS => json_encode([ 'present_value' => 10000, 'annual_rate_percent' => 7, 'years' => 10, 'compound_frequency' => 'monthly', 'contribution' => 100, 'contribution_frequency' => 'monthly' ]), ]); $resp = curl_exec($ch); curl_close($ch); print_r(json_decode($resp, true)); ``` copy ```text require 'net/http' require 'json' require 'uri' uri = URI('https://api.miniwebtool.com/v1/tools/future-value-calculator/run') http = Net::HTTP.new(uri.host, uri.port) http.use_ssl = (uri.scheme == 'https') req = Net::HTTP::Post.new(uri) req['Authorization'] = 'Bearer mwt_live_YOUR_KEY' req['Content-Type'] = 'application/json' req.body = { 'present_value' => 10000, 'annual_rate_percent' => 7, 'years' => 10, 'compound_frequency' => 'monthly', 'contribution' => 100, 'contribution_frequency' => 'monthly' }.to_json resp = http.request(req) puts JSON.parse(resp.body).inspect ``` copy ```text package main import ( "bytes" "encoding/json" "fmt" "io" "net/http" ) func main() { body, _:= json.Marshal(map[string]interface{}{ "present_value": 10000, "annual_rate_percent": 7, "years": 10, "compound_frequency": "monthly", "contribution": 100, "contribution_frequency": "monthly", }) req, _:= http.NewRequest("POST", "https://api.miniwebtool.com/v1/tools/future-value-calculator/run", bytes.NewReader(body)) req.Header.Set("Authorization", "Bearer mwt_live_YOUR_KEY") req.Header.Set("Content-Type", "application/json") resp, err:= http.DefaultClient.Do(req) if err!= nil { panic(err) } defer resp.Body.Close() out, _:= io.ReadAll(resp.Body) fmt.Println(string(out)) } ``` copy ```text import java.net.URI; import java.net.http.*; var client = HttpClient.newHttpClient(); var req = HttpRequest.newBuilder() .uri(URI.create("https://api.miniwebtool.com/v1/tools/future-value-calculator/run")) .header("Authorization", "Bearer mwt_live_YOUR_KEY") .header("Content-Type", "application/json") .POST(HttpRequest.BodyPublishers.ofString("{\"present_value\":10000,\"annual_rate_percent\":7,\"years\":10,\"compound_frequency\":\"monthly\",\"contribution\":100,\"contribution_frequency\":\"monthly\"}")) .build(); var resp = client.send(req, HttpResponse.BodyHandlers.ofString()); System.out.println(resp.body()); ``` how-to call future-value-calculator - Get an API key [Get an API key](/billing/checkout/?plan=starter). Choose the Starter plan or higher to receive a bearer token with access to this endpoint. - Assemble the JSON body Required fields:`present_value`,`annual_rate_percent`,`years`,. See the Request body table above for the full schema. - POST to`https://api.miniwebtool.com/v1/tools/future-value-calculator/run` Headers:`Authorization: Bearer `and`Content-Type: application/json`. Copy-paste snippets in 7 languages are under Code examples. - Parse the response Envelope:`{request_id, tool, tool_version, credits_used, result}`. The typed output lives in`result`. faq frequently asked What does the Future Value Calculator API do? + Calculate future value from a lump sum plus optional recurring contributions. Use it to add this utility without rebuilding formulas, validation, examples, and documentation. How much does one call to Future Value Calculator cost? + 2 credits per successful call. Failed calls (validation errors, 5xx) don't bill. What parameters does the Future Value Calculator API require? + Required fields: present_value, annual_rate_percent, years. Full schema at /v1/openapi.json. Is the Future Value Calculator API deterministic? + Yes — same input, same output, forever. Tool version 2026-04-22; output shape is stable within a major version. Can an AI agent call the Future Value Calculator API? + Yes. Connect to https://api.miniwebtool.com/v1/mcp over the Model Context Protocol. The agent discovers `future-value-calculator` with its JSON Schema automatically, so the model can plan while MiniWebtool handles the exact tool result. What format does the API return? + JSON with a stable envelope: `{request_id, tool, tool_version, credits_used, result}`. Errors are RFC 7807 `application/problem+json`. mcp use from an AI agent Every endpoint on this site is also exposed via the [Model Context Protocol](/docs/#mcp) at`https://api.miniwebtool.com/v1/mcp`. Claude, Cursor, and any MCP-capable agent can discover this tool (`future-value-calculator`) and its JSON Schema automatically — no client codegen. ```text # List tools the agent can call curl -s https://api.miniwebtool.com/v1/mcp \ -H 'Content-Type: application/json' \ -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' \ | jq '.result.tools[] | select(.name=="future-value-calculator")' ``` see-also related finance tools [ Doubling Time Calculator Calculate exact doubling time, Rule of 72 estimates, or the rate required to do… ](/tools/doubling-time-calculator/) [ Debt Consolidation Calculator Estimate a consolidated debt payment and interest cost. ](/tools/debt-consolidation-calculator/) [ Bond Yield to Maturity Calculator Calculate bond yield to maturity with current yield and return metrics. ](/tools/bond-yield-to-maturity-calculator/) [ Markup Calculator Calculate markup percentage, selling price, cost, profit, and margin. ](/tools/markup-calculator/) API OPERATIONAL v1 · OpenAPI 3.1 · MCP 2025-06-18 [terms](https://miniwebtool.com/about/terms-and-disclaimer/#api-terms) [privacy](https://miniwebtool.com/about/privacy/#api-privacy) [llms.txt](/llms.txt) [consumer site →](https://miniwebtool.com) © 2026 miniwebtool